Comprehensive Description
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الإنجليزية
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المقدمة من Smithsonian Contributions to Zoology
Nocomis raneyi
BULL CHUB
Hybopsis kentuckiensis—Jordan, 1889:123 (Roanoke dr. [in part], 126 (Tar dr.), 129 (Neuse dr. [part]).
Hybopsis species.—Robins and Raney, 1956:31.
Hybopsis (Nocomis) species 2—Reno, 1969b: 739.
Nocomis micropogon.—Burton and Odum, 1945:186 [part].
Nocomis species.—Raney, 1950:184
DIAGNOSIS.—Differs from the other micropogon group members in: mouth small (Figure 5); snout short (Figure 6, Tables 17, 20, 21); body deep, more compressed laterally in adult males; head tubercles in adults often more than 100 (Table 5) and densely developed from tip of snout to interorbital area; caudal fin more sharply forked; pharyngeal tooth arch stout with short limbs (Figure 18).
DESCRIPTION.—Morphometry: Proportional measurements expressed in thousandths of the standard length are given in Table 23 for the holotype, 5 male paratypes, 53 to 227 mm, and 5 female paratypes, 68 to 180 mm. Because of the allometric growth, additional proportional data are given in Table 25 for 13 characters of 24 mature males having a mean length of 200 mm and ranging from 172 to 242 mm. N. raneyi is compared in these characters with the adults of the three other chub species from the study area. Many proportions increase with increase in body length. The diameter of the orbit is an exception, decreasing with increase in body length, a characteristic of all known species of Nocomis. A number of morphometric values may appear higher in males than in females, but when plotted against body length there are no appreciable differences. The higher values in the males relate only to the larger body size attained by them.
The head is pointy and the body slender in the young and juveniles of N. raneyi, resembling N. platyrhynchus and unlike the more robust body and deeper head of N. leptocephalus (Figure 17). As the males approach maturity the facial features become greatly modified, the forehead becomes deep and rounded and the body somewhat slab sided (compare Figure 17, juveniles; Figure 16, tubercle-bud stage in male; Plate 14, adult female in tubercle-spot stage; Figures 10, 12, 15, nuptial tubercle stage of breeding male). In the development of the facial features at maturity N. raneyi resembles N. platyrhynchus more closely than N. micropogon or N. leptocephalus.
Two morphometric characters, although showing allometric growth, proved significant in segregating a majority of specimens of N. raneyi from its two species cognates in the micropogon group; these were gape width (Figures 5, 7) and snout length (Figure 6), when related to body length. The relationships of gape width plotted against standard length (Figure 5) is based on 146 N. raneyi, 88 N. platyrhynchus, and 151 N. micropogon from specimens of all sizes, sexes combined, and sampled over the ranges of the species. The tests of difference of slopes and heights (intercepts) of pairs of regression lines were performed by analysis of covariance (Snedecor, 1956:394–399). F values yielding probabilities greater than .95 were considered significant. The slope of the regression of gape width (as percent of SL) on standard length of N. raneyi is significantly different from N. platyrhynchus (F=64.18) and N. micropogon (F=60.51). The slope of the regression lines for N. micropogon and N. platyrhynchus do not differ significantly (F=2.97) but the heights are different (F=42.19). The regression equations are N. micropogon, y=.0294X+6.24, n=92; N. platyrhynchus, y=.0247X+6.07, n=103; N. raneyi, y=.0075X+6.68, n=96. The same collections were used, as above in plotting snout length against standard length for the same three species (Figure 6). The consistently shorter snout (average) is shown for any respective body length in N. raneyi, although the differences are not of the same magnitude as in the gape width. The influence of increase in body length on the gape width and snout length is shown in Tables 17, 20 and 21 for N. raneyi and N. platyrhynchus, the specimens divided into three size groups, 50 to 99 mm SL, 100 to 149 mm SL and 150 mm SL and larger. When gape width is plotted against snout length for each specimen, only 60 percent separation occurred in the smaller sized group and about 88 percent in the two larger groups.
The preopercle-opercle suture, as it approaches the angle on lower head, is directed forward in almost all specimens of N. raneyi. In a sample of 400 specimens from three drainages, the James, Roanoke, and Chowan, the suture was considerably directed forward (an angle of 10 to 20 degrees) in 75 percent of the sample; 20 percent with suture slightly directly forward; and 5 percent with suture perpendicular or posteriorly directed in respect to the horizontal axis of body.
The fin shapes among the species of the micropogon group are relatively similar (Figures 12, 13, 14, 17, 25) except the caudal fin in N. raneyi, which is more deeply forked, especially noticeable in the subadults and adult females.
The intestine is simple, elongate and S-shaped, frequently with an accessory loop (47 of 49 specimens from over its range). This organ differs greatly from that of N. leptocephalus, in which it is whorled and extends under the intestional bulb (Figure 8).
The following are other general features of head and body. The dorsal contour of the head on specimens without cephalic swelling is almost straight to gently curved and slopes slightly to moderately downward from the occiput to the internasal region, more so in the anterior portion. A slight to moderate dip in contour, sometimes causing a small hump, is usually present in the internasal region, except on some of the large males. The snout anteriorly is rather short and subconical or moderately rounded. On some specimens the tip of the snout appears more elongate and/or acuminate. The head ventrally is almost straight and slightly less oblique to the horizontal axis than the dorsal contour of the head.
The mouth is small in the young to moderate in size in adult males; it is oblique and subterminal, being slightly to moderately overhung by the snout tip. The lower jaw is included. The jaw angle is positioned at or slightly posterior to a line ventrad from the posterior nostril. In lateral view the upper lip is generally oblique, being slightly to moderately slanted downward; however, in some specimens the anterior half of the upper lip is directed slightly above the horizontal, the posterior half directed below. The lower lip is straight and directed somewhat downward. In ventral view the lips are semicircular or they are round anteriorly, the sides diverging, straight, or curving medially. The lateral portion of the upper lip extends to the ventral head margin except at the jaw angle where it is slightly less than the head width at that point. The premaxilla is protractile and a deep groove is present around the entire lips except along the anterior portion of the lower lip where it is absent. The lips are fleshy, appearing more enlarged in nuptial males. The single pair of terminal maxillary barbels are short and sometimes not excised from the deep groove behind the jaw angle, and are abundantly supplied with taste buds.
The eye is small, the fleshy orbit is round or slightly obliquely or horizontally elongate. The lachrymal bone is oblique to the horizontal, especially in adult males, and reaches the upper lip just above which an obvious crease in the skin is present along its anterior end. The branchiostegal membranes are united to the posterior isthmus, the distance between the points of insertion of the membrane are about half the gape width. The epidermis in the interbranchial isthmus area is longitudinally folded; below the mouth it is folded at right angles to the longitudinal axis.
The body is elongate and subterete, slightly compressed in subadults to moderately compressed in nuptial males, widest and deepest midway between occiput and origin of dorsal fin. The back is slightly to moderately elevated above the occiput level, highest at the dorsal fin origin or just anterior to this. The predorsal body contour is straight or slightly convex, somewhat oblique to the horizontal axis, and is continuous with the posterior head dorsum contour, or a slight abrupt rise to the body level is sometimes present at the occiput. The postdorsal contour is straight and slopes slightly more downwardly than the predorsal contour; it is upturned beginning just anterior to the procurrent caudal fin rays. The dorsal fin base is straight but usually more oblique to the horizontal axis than the postdorsal contour. The ventral body contour is gently rounded, generally not deep, from the isthmus to the anal fin origin, straight and moderately directed upward at the anal fin base, and then almost straight and sloping slightly upward to a point just anterior to the procurrent caudal fin rays where it is downwardly curved. The caudal peduncle is moderate in length and depth, rather narrow in width.
The lateral line is complete, slightly downwardly curved anteriorly, and straight posteriorly. The line begins on the body at the posterior opercle insertion, slopes quite obliquely downward for a short distance over the cleithrum to a point slightly above the midlateral level, then slopes slightly downward through the first seven to nine vertical scale rows to the midlateral level or to a point slightly below this; in the latter case it slopes gently back upwards and attains the midlateral level at a point usually just posteriad to a vertical line from the dorsal fin origin. Upon attaining the midlateral level it is rather straight and horizontal to the posteriormost scale overlying the bases of the midcaudal fin rays.
The urogential papilla in both sexes is fleshy and moderate to rather large in size, the length about 1 to 1.5 times the greatest width. It changes in shape from bulbous to subconical with a small orifice in the adults. Much of the papilla rests in a depression before the origin of the anal fin, being more excised from this in larger specimens.
The entire body, except the breast, is scaled. Laterally, the exposed portion of the anterior scales is higher than long, especially just behind the cleithrum where they appear diamond shaped, although the posterior margin is somewhat rounded. The exposed portion of the lateral caudal peduncle scales is about equal in height and length, appearing square. The posterior margin of lateral line scales is usually slightly to moderately indented. The dorsal and ventral scales are quite variable in size and shape; anteriorly they tend to be smaller and imbedded.
Cutaneous sense organs are present over the entire head, laterally and dorsally on the scales of the first one or two vertical scale rows, ventrally back to about the anal area, and on the upper and lower surfaces of the interradial membranes of the pectoral fin. They are largest on the head ventrally, especially on the lips.
The alimentary tract is a simple loop, the longitudinal lengths of the tract are straight or slightly curved. The intestinal bulb extends posteriad on the right side to just before the vent and, unless full of food, is only slightly wider than the intestine. The intestine then bends sharply mediad and anteriad to just behind the pericardium (the ascending intestine), and it sometimes bends sharply to the left side and posteriad to the vent (the descending intestine). Usually, instead of the ascending portion bending directly into the descending portion, an additional short loop, about 10 to 30 percent (sometimes to 50 percent) the length of the descending portion, occurs on the left side at the end of the ascending intestine and laterad or dorsad to the descending portion into which it leads. Sometimes a short anterior length of the ascending and descending portions is “kinked” laterad to the right side.
The fins are moderate in length except the slightly elongate caudal. The margin of the pectoral fin is moderately angulate to round. The free margin is angulate from the tip of rays 1 to 10 (the apex at ray 4, the longest ray) or moderately rounded between these rays; it is then broadly rounded along the tips of the much shorter posterior rays to the posterior base. The margin of the pelvic fin is broadly rounded or almost straight with rounded corners, ray 3 or 4 being the longest. When appressed, the pelvic fin may reach or is quite short of the urogenital papilla base. The tip of the anal fin, anteriorly, is slightly or well rounded to its longest ray (ray 2 or 3), then straight or slightly incurved to the last ray. The origin of the dorsal fin is positioned well anterior to the midbody point and usually over the origin of the pelvic fin, sometimes slightly posterior to the latter. The anterior tip is pointed or slightly round; ray 1 or 2 is longest and falls short of the posterior rays when appressed. The margin of the dorsal fin is usually straight, sometimes slightly incurved. The caudal fin is well forked, the fork apex is broadly rounded or very obtusely angulate. The lobes are always subequal in length; the upper lobe always longer and its tip usually narrower. The tip of the upper lobe in young and juveniles is pointed or round, in adults it is acuminate. The lower lobe is broadly rounded in young and usually quite pointed in adults. The well-developed procurrent caudal rays form a distinct middorsal and mid-ventral ridge on the posterior caudal peduncle.
Meristic characters: Values for squamation counts for N. raneyi are close to N. platyrhynchus and they are somewhat intermediate between the lower values usually for N. micropogon and N. leptocephalus and higher values of N. effusus (Lachner and Jenkins, 1967). The range of the mean values for N. raneyi taken usually from five drainages, with the count of the holotype in parentheses, follow: circumferential scale rows (Table 12), 32.9 to 33.4 (35); lateral line scale rows (Table 8), 41.0 to 41.6 (41); scale rows above lateral line (Table 11), 7.3 to 7.7 (8); scale rows below lateral line (Table 11), 6.1 to 6.4 (7); caudal peduncle scale rows (Table 14), 16.1 to 16.7 (17); pectoral fin rays (Table 16), 16.8 to 17.1; total vertebral numbers (Table 15), 40.9 to 41.6.
Assigning numerical values for the degree of breast squamation (Table 18) was useful in demonstrating specific differences in the micropogon group as well as showing certain racial differences. N. raneyi almost always has a scaleless breast in the James, Chowan, and Roanoke Rivers, whereas it is about 50 percent scaled in the Tar and Neuse Rivers.
Tuberculation: Data pertaining to tubercle development, distribution, and numbers is summarized in Tables 1, 3, 4, 5. Early tubercle development is shown in Figure 3c. The relationship between increase in tubercle numbers with increase in standard length is shown in Figure 4. The distribution of head tubercles is illustrated in Figures 9, 10, 11, 12 (holotype), and 16 for immature specimens and nuptial adults.
The tubercle pattern and the relationship between increase in tubercle numbers with increase in body length is similar in both sexes. At first inspection this sex similarity may not appear correct because the tubercle spots are difficult to discern in the females (at most, they develop only to a fine bud stage), except in the largest specimens, and initial trials at counting will give lower improper values. Also, the males attain a larger size and a greater average number of tubercles. The tubercles first appear in N. raneyi as small, light spots, often 15 or more, and extend from the anterior internasal line to the midinterorbital line (Figure 3c). They rarely commence development in specimens under 60 mm SL, and they are often not discernible at lengths of 60 to 85 mm SL. With increase in body length, the tubercles develop posteriorly on the head, but almost always stop development at the posterior interorbital line (Table 1). The snout and subnasal tubercles are last to develop in N. raneyi. The full complement of tubercles, which may exceed 200 in nuptial males, extends from the tip of snout (Figure 9) to the posterior interorbital area, and includes a supraorbital ring and two or three irregular rows on the lachrymal area. The tubercles are closely spaced from the anterior interorbital to the tip of snout. N. raneyi differs in the latter character from N. platyrhynchus, which sometimes shows reduced tuberculation before the anterior internasal area, and differs considerably from N. micropogon, which usually has a hiatus of tubercles in this area. A character exclusive to N. raneyi is the continued increase in numbers with increase in body length (Table 5; Figure 4). No other species of Nocomis has this characteristic. The head tubercles of N. raneyi are relatively uniform in size, but they are somewhat larger in the area extending from the internasal to the interorbital. The largest tubercles are about 1.8 to 1.9 mm in diameter. The smallest tubercles occur on the snout. Tubercles average somewhat larger in N. platyrhynchus. They are large in N. micropogon and very large in N. leptocephalus. All of our data on size of tuberculate or scarred adult specimens (Table 3) and the body length when tubercle buds first appear (Table 4) indicates that N. raneyi matures at an appreciably larger size than N. micropogon or N. platyrhynchus. Observations of nuptial males of N. raneyi attending their mound-nests corroborates this point.
Small tubercles are present on the dorsal portion of the rays of the pectoral fin, in a single row per ray, and they occur modally on rays 2 to 5 or 6, rarely on rays 2 to 7 and 8.
Nuptial crest: Because of the difficulty in capturing the adult males, which are secretive, solitary, and prefer the deeper waters, complete sequential development of the nuptial crest with maturity is not determinable from our material. The swelling first appears in the internasal to snout area and enlarges to a rounded “cocks comb” that extends to the occiput (Figure 12). An immature male specimen, 194 mm SL, (Figure 16a) taken 6 June 1963 from Craig Creek, has the typical sharp snout of smaller immature males or mature females but has a very slight internasal-interorbital swelling. Three later stages in the development of the nuptial crest are seen on the following specimens of N. raneyi:198 mm SL, captured 28 June 1963 with moderately swollen area from snout to occiput (Figure 10b); 232 mm SL, captured 23 May 1964 with large crest (Figure 10a); and 242 mm SL, taken 29 May 1964 with very large crest (Figure 12). Many very large nuptial N. raneyi have been observed during the reproductive period in Craig and Catawba Creeks, James drainage over the past several years by the first author and all specimens had large crests. A postnuptial male, 229 mm SL (Figure 13), taken 21 June 1946 from the Roanoke River, has a moderate head swelling, but whether this was its maximum development during spawning or it had since receded somewhat was not determined.
The crest in N. raneyi is shaped and located differently than in N. micropogon and N. leptocephalus. Both of the latter species develop higher, more dome-like crests, that are more forward on the head, particularly in N. leptocephalus.
Pharyngeal dentition: The pharyngeal tooth count is 4–4 in 21 pairs of arches in specimens from the James, Roanoke, Tar, and Neuse River drainages. The teeth are very stout and moderate in length. The arch is stout, broad, with short upper and lower limbs. In the large N. raneyi (Figure 18) the arch is massive, and probably stoutest of all Nocomis. The pitted surface is deeply sculptured, but the pits are not usually as extensively developed as in other species of Nocomis.
Coloration: Juveniles, adult females and subadult males from the James and Roanoke River drainages show no significant local or geographic color difference in life or in preservation, or among these size stages.
The characteristic scale color pattern on the body, dorsally and laterally, ventrad to 1–3 scale-rows above the pelvic fin base, has two basic aspects, the dark scale margins and the light median scale color. In the lateral line area the exposed portions of the scales are sharply bicolored. The dark anterior margin (the excised scale pocket membrane) and the posterior margin meet at the dorsal and ventral edge of the scales, thus surrounding the light median area. The inner edge of the anterior margin is vertically straight or slightly curved except in the lateral line scale-row where it is indented at the level of the lateral line canal pores. The inner edge of the posterior margin follows the curve of the actual scale margin; its outer edge extends to and is darkest at the scale edge. The anterior margin is generally slightly wider than the posterior margin. The scale margins are slightly wider on the anterior body scales than those on the posterior body. A reduction in scale bicoloration occurs ventrad and dorsad; the margin decreases in width and intensity ventrad until absent, and increases in width and and intensity dorsad, where, on the dorsum, the dark margin nearly or entirely fills in the light median area. Smaller juveniles generally have narrower margins than the larger adults; thus they have average lighter colors. The colors of the margins are, on the dorsum, usually black-olive, some brown-olive, and grade from dark olive dorsolaterally, olive or yellow-olive in the lateral line area to pale olive or pale yellow-olive below. Some tints of green iridescence also appear on the margins. In some specimens there is a sharp body bicoloration, effected by appreciable lighter colors in the lateral line area.
The medians of the lateral body scales are iridescent silver with a cast of yellow to olive in most specimens. Iridescent violet and green hues are also present in the lateral region of many specimens, and these colors are particularly evident in sunlight. The silver color is almost entirely replaced dorsad by the dark scale margins. The belly is pearly white whereas the breast, where scales are absent, is less lustrous or gray-white. An iridescent silver-yellow to silver-olive middorsal stripe about one scale in width is developed from the occiput to the dorsal fin and on the anterior half to the entire postdorsum of specimens up to 120–160 mm SL.
A horizontal lateral band occurs in most smaller juveniles and in a few specimens up to about 130 mm SL, including some adult females. When fully developed, it extends from the tip of the lachrymal bone (interrupted by the orbit) through the lateral line area to the area over the caudal base, and ranges 1.5–2.5 scales in width, narrowing just before the caudal base area and then widening slightly. The intensity is variable, generally being darkest, but rarely blackish, in smaller juveniles. It is generally darkest over the caudal peduncle and, when faint, it is usually present only in this area. The lateral band is effected by a relative darkening beneath the medians of the scales and lighter medians 1–2 scale rows above.
The basicaudal spot is small, generally amorphous, confluent or slightly separated from and usually darker than the end of the lateral band. It is almost always absent from specimens larger than 120 mm SL, and often in many smaller ones.
A black or blue-black, slightly curving bar occurs from the pectoral fin base to the dorsum behind the opercular opening, entirely over the cleithrum or extending slightly posterior to it.
The head, dorsally, to the snout tip is black, brown, or dark olive. The occipital line is slightly lighter than the head dorsum. In some large adult males a dark blue cast occurs on the head and anterior dorsal part of the body. The head, laterally, over the upper operculum, below the orbit and over the lachrymal is largely yellow-olive to dark olive with iridescent silver, gold and green sometimes masking the olive; the iridescence is most intense along the upper edge of the operculum. The outer, upper lip is a lighter olive than the snout, dorsally. The ventro-lateral head is silvery with some golden reflections. The head ventrally, including the lower jaw, is white to gray-white. The opercular membrane is olive laterally, and pale olive ventrally. The inner iris in almost all specimens is narrowly bordered by iridescent yellow, gold, orange, or combinations of these colors. This iris ring is sometimes interrupted by the black to light olive areas of the outer iris, or it is absent.
Fin coloration is variable in its intensity and areas of development. The pale yellow to reddish colors are almost entirely confined to the inter-radial membranes and the membranes between ray branches; sometimes they shade into the rays of juveniles. Membranes lacking these colors are hyaline to dusky gray, sometimes dusky olive in the larger specimens. Portions of the fin rays appear blackish since melanophores occur along the rays and ray joints, generally being heaviest on the dorsal fin and lightest, or sometimes absent, on the anal and pelvic fins; a greater deposition occurs in larger specimens. Color is almost always lacking along the fin margins, the margin being hyaline to dull white, generally widest on the anal and narrowest on the caudal.
The typical caudal fin coloration is a light red in the distal ?–½ of the fin membrane, deepest in the distal portion of the lobes and usually extending basally from these. In a number of specimens the basal portion of the medial membranes is suffused with pale red. The reddish shade is generally deeper in larger specimens. In some juveniles it is orangish red; in an immature female 110 mm SL, it was orange. In a few specimens the membrane color is very weak or absent. A recently preserved, large adult female from the Neuse River drainage had a light red outer caudal. The rays are yellowish olive to dark olive, tending to be colorless and clear in small specimens. In larger specimens, the thick skin over the outer edge of the most ventral ray is light gray.
The distal half of the dorsal fin membrane is usually light red to orangish red; sometimes this color is suffused through the entire membrane. The red is deepest in the distal portion of the anterior membrane. The rays are yellow-olive to olive, or colorless in smaller specimens.
The pectoral fin rays are dusky yellow to pale olive, being the most colorful distally. The membrane is gray-white, often with an orange suffusion distally. The thick skin over the first ray is very dark except for the gray-white anterior edge.
The distal pelvic fin ray is light or moderate yellow to yellow-olive, and grades basally to light olive or colorless; the medial and distal rays often have a tingle of light orange. Most of the first ray and the distal portion of rays 2 and 3 are milky white or yellow-white. The membrane is clear to light gray.
The anal fin is the least colorful. The rays are pale yellow to pale olive over ½–? of their length. The first ray is white or yellow-white. The membrane is clear to dull white.
The striking color features of the nuptial male in life are a pink or rosy on the head, body and fins and the accentuation of certain other body colors over those of nonbreeding adult males. The most highly colored male we examined (USNM 194625, 237 mm SL) had well-developed tubercles and a large crest, captured in the James drainage, 23 May 1964, probably in the midst of breeding activities for many fresh nests were about. The most intense nuptial color was rosy, located from the posterior end of the postopercular bar, in the level from one scale-row below the lateral line to the upper pectoral fin base, posterior to the pelvic fin base. The color was deepest in the anterior portion of this area. It extended as light pink to the area over the anterior anal fin base, where it ended. The color graded to faint pink on the belly and was absent from the scaleless breast area.
The lower head, laterally, below a line from about the jaw angle obliquely to midheight of the opercle, was pink to light pink with some portions of this area being suffused with olive. The upper opercular area was olive. The head, ventrally, including the lower jaw (but not the upper jaw) was pink, deepest over the distal portion of the branchiostegal area.
A heavy silver-bronze iridescence colored the medians of the scales of the body, laterally, above the lateral line and it was present in the medians of only the lightest dorsal scales. A faint pink suffused the medians of the third to fourth scale-rows above the lateral line between the postopercular bar and pelvic fin levels.
The dorsal fin membranes were light pink (with some dusky olive in the basal third). In addition to the yellow, olive, and orange colors of nonbreeding specimens, the pectoral and pelvic fins had a suffuse pink, slightly lighter than that of the dorsal fin. There was only a very slight pink suffusion in the distal anterior membranes of the otherwise typically colored anal fin. The caudal fin lacked pink coloration. A milky-white color occurred along the tips of the dorsal, pectoral, pelvic, and anal fin rays.
Three highly tuberculate (one with many tubercle scars) males, 197, 212 and 242 mm (holotype) SL with small to large crests, were captured on 28 June 1963, 15 May 1963, and 29 May 1964, respectively, from the upper Roanoke drainage (first specimen) and the James drainage. These and many observations by Lachner of spawning males provided additional data on life coloration. The significant feature of the breeding N. raneyi (and other Nocomis) is to “turn on” his colors to high intensities just prior to or during the spawning acts.
Only slight color differences were found among these males and the male described (USNM 194625, 237 mm SL) but the intensities differed appreciably. The intensity and area of development of the pink-rosy coloration was about the same as described above but it could be more or less intense depending on the spawning “peak” of the male. Pink color was usually absent from the fins. In some males in the “peak” of spawning all fins had a lemon-yellow margin. The lateral body medians of the scales above the lateral line in the holotype were iridescent silver-bronze. In some, it was iridescent olive-yellow, a slightly brighter yellow than that seen in any other specimens of N. raneyi.
The light red caudal fin coloration occupied the distal half of all membranes in most of the males, but it was confined to the distal half of the upper lobe in the holotype. In some active, spawning males the caudal fin is dusky-olive. Melanophore deposition along the rays and ray joints was heaviest in the largest nuptial males, particularly in the distal half of the dorsal fin, but in the smaller males it was no heavier than that in large nonbreeding adult males. The same is true of the dark scale margins. No trace of a dark lateral band was observed.
After chubs are placed in preservative (10% formalin and alcohol), the iridescent colors are rapidly lost. A few days thereafter all that remain are the dark colors of the scale margins, fin rays, lateral band and caudal spot and various tones of black-gray to light gray.
Melanophores underlie the dark scale margin and dark head coloration seen in life. Their patterns in alcohol are about the same as the overlying life colors and are shown in the illustrations.
With the fading of the iridescent median scale colors, certain patterns appear and some become more pronounced on the body. These are produced by the “subscale” melanophores which are located on the undersides of scales and on the musculature. The dark horizontal midlateral band on the body seems to remain in well-preserved specimens that possessed it in life. The band is produced largely or entirely by a heavier concentration of subscale melanophores. Other shades of lighter lateral and blackish dorsal medians of scales are also due mainly to subscale melanophores. The light middorsal stripe of living specimens turns darker than the adjacent dorsum color in preservative. In many specimens, slightly dark horizontal lines, running nearly or entirely the length of the body, occur on the body laterally, above the lateral line, and sometimes to 3 to 4 scale-rows below the lateral line. The lines are produced by the slightly heavier deposition of subscale melanophores in the areas beneath the dorsal and ventral edges of the scales rather than beneath the medians of the scales.
A slight average difference in coloration exists in the lateral margins of the scales between the sexes, this being noticed only in preserved specimens. Many adult females have slightly wider anterior and posterior scale margins than those of males of similar size.
POPULATIONS.—The drainage populations of N. raneyi are similar. Only two characters show distinctive interdrainage divergence, the degree of breast squamation (Table 18) and the number of vertebrae (Table 15). Both characters partially differentiate the populations in the James, Chowan and Roanoke drainages from those in the Tar and Neuse. Breast scales in the James, Chowan and Roanoke drainages are almost always absent (93% of 138 specimens) and the breast was never half scaled. The Tar-Neuse populations had only one of 41 specimens naked and about 80 percent had the breast scaled about one third or more. The mean values for total vertebral numbers were practically the same for the Tar and the Neuse drainages (40.9 and 41.0) and lower than in the three more northern drainages (41.4, 41.6, and 41.4).
REPRODUCTION AND GROWTH.—The male of N. raneyi constructs a mound-nest (as in all species of Nocomis) of gravel that he transports in his mouth. The completed nest may exceed three to four feet in diameter. (The reproductive behavior of the species of Nocomis, including N. raneyi will be treated in part 6, see p. 2). N. raneyi attains the largest size of all the species in the genus, the largest male examined was 266 mm SL and the largest female, 180 mm SL, both from the Neuse drainage. All nuptial males exceeded in length the largest female captured. Several large males over 200 mm SL aged by scale analysis were in their fourth and fifth year of life.
ETYMOLOGY.—This species is named after Edward C. Raney, scientist and teacher, Cornell University, Ithaca, New York, whose enthusiasm and guidance placed many American students on the professional pathway to ichthyology.
The vernacular name, bull chub, was composed by us because of the large size and aggressive habits of the crested nuptial males during the spawning period. The nuptial N. raneyi sometimes engages in lengthy battles with other nuptial males of his own kind when nesting territories overlap. The native people in southwestern Virginia refer to N. raneyi as a chub, pinkbelly chub, hornyhead or nestmaker, but they generally do not differentiate among the four species in the area.
MATERIALS EXAMINED.—A total of 106 collections from 84 localities in five drainages were examined.
Holotype: USNM 194633, a nuptial male 242 mm in standard length, captured in Craig Creek, Craig County, Virginia, 2.2 road miles on Rt. 311 southwest (upstream) from Newcastle, at first bridge from Newcastle, 29 May 1964 with shocker by Robert E. Jenkins and Robert L. Miles. Five paratypes, USNM 194266, were taken with the holotype.
The Craig Creek system of James drainage and the Roanoke drainage materials are designated as paratypes.
The collections are listed below by drainages and major tributaries in progressive upstream order; following the collection date is the number of specimens captured (in parentheses). Designations given as “same locality” or “same collection” refer to the immediately preceding locality or collection.
James River Drainage, Virginia
Craig Creek, Botetourt County.—USNM 194624: at 1 mi above mouth, second bridge over Craig from Eagle Rock, 23 May 1964 (3). USNM 177397: at 2.5 mi above mouth, 3 airmi SW Gala, 3 July 1958 (26). USNM 194625; jet. Rtes. 615–683 (at suspension bridge) 3.3 rdmi NE (downstream) Oriskany, 15.4 rdmi NE Newcastle on Rte. 615–42, 23 May 1964 (3).
Craig Creek, Craig County.—USNM 194626: bridge on Rte. 606 leading to Camp Easter Seal (Rte. 606 turns off Rte. 615 at 9.2 rdmi NE Newcastle), 24 May 1964 (2). USNM 194627: at 2.3 airmi NE Newcastle, 6 June 1963 (29). USNM 194628: Pinetop, 2 airmi NE Newcastle, 11 May 1963 (15). USNM 194629: Rte. 616 ford, 1.2 airmi NE Newcastle, 16 August 1957 (133). USNM 194630: same locality, 12 October 1960 (71). USNM 194631: same locality, 15 May 1963 (172). USNM 194632: holotype locality, 16 May 1957 (16). USNM 194634: Rte. 311 bridge, 3 rdmi SW Newcastle, 19 August 1958 (4). UR 1538: Rte. 311 bridge, 5.6 rdmi SSW Newcastle, just N Abbott, 27 June 1963 (2).
Johns Creek, Craig County.—CU 20356: along Rte. 42 in Newcastle, about 05 mi above mouth, 5 June 1951 (15). CU 24859: same locality, 7 July 1952 (13). USNM 194635: same locality, 3 October 1953 (12). USNM 194637: at 1.8 mi W (upstream from) Newcastle in Nutter Mountain gorge, 16 August 1957 (4). USNM 194638: at 4.8 mi W Newcastle, 16 August 1957 (25). UMMZ 181830: at 7 mi above Newcastle, 27 August 1941 (1). CU 48564: at 4.35 rdmi W jet. Rtes. 311–658 on Rte. 658, 7.75 airmi W Newcastle, 10 May 1965 (8). CU 48445: at 1.3 rdmi SW jet. Rtes. 632–635 on Rte. 632, 10.8 airmi WSW Newcastle, 27 March 1965 (2). USNM 194639: most downstream Rte. 632 bridge, 12 airmi WSW Newcastle, 4.75 airmi NE (downstream) Maggie, 1 October 1957 (2). USNM 194640: second Rte. 632 bridge upstream from Newcastle, 2.8 airmi NE Maggie, 30 May 1964 (7). UR 1796: first Rte. 632 bridge 2 rdmi NE jet. Rtes. 632–658 at Maggie, 27 June 1963 (24). CU 47594: at 1 rdmi NE jet. Rtes. 632–656 at Maggie, along field off Rte. 632, 29 May 1964 (27).
Chowan River Drainage, Virginia
Sappony Creek, Sussex County.—CU 16911: Rte. 40 bridge, 22 mi W town of Stony Creek, 27 March 1949 (3).
Stony Creek, Dinwiddie County.—CU 47335: at 1.2 mi S Dinwiddie on Rte. 1, 21 March 1948 (18).
Nottoway River, Brunswick-Dinwiddie County line.—USNM 177357: Rte. 1 bridge, 29 July 1958 (8).
Meherrin River, Lunenburg-Mecklenburg County line.— USNM 194642 (2 collections lumped): (a) Rte. 138 bridge, Union Mill, 5.1 airmi NNE South Hill, 29 July 1958; and (b) bridge just N Ogburn, 7 airmi NW South Hill, 3 September 1958 (42). CU 43628: same collection as (b) (1). USNM 194258: Rte. 49 bridge, 31 July 1958 (2).
Roanoke River Drainage,
Virginia and North Carolina
DAN RIVER SYSTEM
North Carolina, Rockingham County.—USNM 171727: Leaksville, 6 April 1947 (10).
Virginia, Henry County.—USNM 171593: Beaver Cr., 15 mi NW Martinsville, 22 June 1946 (1). USNM 194261: Town Cr., trib. Smith R., Rte. 604 bridge, 1.75 mi SW Henry, near railroad bridge, 6 August 1958 (1).
ROANOKE RIVER SYSTEM, VIRGINIA
Otter River, Bedford County.—USNM 171595: at 4 mi NNE Bedford, 21 June 1946 (13). USNM 166406: at 4 mi NNW Bedford on Rte. 43, 5 September 1947 (4). USNM 166405: at 5 mi NW Bedford on Rte. 43, 9 June 1947 (11).
Otter River, Campbell County.—UMMZ 181434: Rte. 682, S of Evington, 12 June 1956 (3).
Pigg River, Franklin County.—USNM 163436: Rte. 220 bridge, 1 mi S Rocky Mount, 3 April 1948 (106). USNM 194601: same locality, 19 June 1962 (2).
Blackwater River, Franklin County.—USNM 194602: Rte. 616 low-water bridge, 3.7 airmi SE Scruggs, 7.8 airmi SSE Haleford, 11 August 1958 (49). USNM 194605: same locality, 5 July 1961 (28). USNM 194606: at 0.75 mi downstream from Rte. 670 bridge and gauging station, 3.1 airmi SSW Scruggs, 4.6 airmi W Bedford-Franklin-Pittsylvania Co. line, 5 July 1961 (1). USNM 194603: Rte. 670 bridge by gauging station, 2.7 rivermi upstream from mouth Gills Cr., 7.2 mi S Haleford, 11 July 1958 (3). OSUMZ 5991: same locality, 5 July 1961 (68). USNM 194609: at 4.8 airmi SW Scruggs, 8.6 airmi SSW Haleford, 11 August 1958 (18). USNM 194610: near Crafts Church, 7.8 airmi W Bedford-Franklin-Pittsylvania Co, line, 6 July 1961 (62). USNM 177395: at 3.8 airmi NE Redwood, 8.2 airmi ENE Rocky Mount, 5 July 1956 (19). USNM 177376: Rte. 122 bridge 4 airmi NE Rocky Mount, 5 July 1956 (6). USNM 194611: same locality, 7 July 1958 (7). USNM 194612: at Blaine in rocket fuel plant area just E of Rte. 220 bridge, 3 airmi NNE Rocky Mount, 22 August 1957 (11). USNM 194613: same locality, 4 July 1961 (109). USNM 194614: same locality, 6 April 1963 (69). USNM 194615: Rte. 220 bridge, 2.8 mi NNE Rocky Mount, 21 August 1957 (3). CU 25032: Rte. 919 (old Rte. 220) bridge, 2.5 airmi NW Rocky Mount, 22 June 1946 (1). CU 47595: same locality, 5 July 1956 (21). UMMZ 181433: same locality, 17 May 1931 (3). USNM 194617: jet. Rtes. 643–732–737, 4′.75 airmi WNW Rocky Mount, 15 October 1961 (41). USNM 194618: Rte. 740 bridge, 1.8 airmi NE Calloway, 15 October 1961 (9). USNM 194619: North Fork Blackwater along Rte. 641, 2 airmi NE Calloway, 14 October 1961 (14).
Blackwater System, Gills Creek, Franklin County.—USNM 194607: about 4–5 rivermi above mouth in Blackwater, 5 airmi SE Hales Fort Church, 2.1 airmi SW Scruggs, 6 July 1961 (2). USNM 194604:25 mi SW Scruggs, 5.9 airmi SSW Haleford, 7 August 1958 (1).
Back Creek, Roanoke County.—USNM 194620: Rte. 657 bridge, 0.5 mi from Rte. 220 intersection, 4.5 airmi S Roanoke, 3 July 1961 (7).
Roanoke River, Roanoke County.—USNM 40240: at or near Roanoke, 31 July-2 August 1888 (1). USNM 166404: Salem, 21 June 1946 (1). UMMZ 181431: at 2 mi above Salem, 13 June 1956 (3). CU 20769: Glenvar, 6 June 1951 (1). CU 24771: same locality, 30 June 1952 (2). UR 2025: same locality (at RR station just off Rte. 11), 11 July 1963. (11). USNM 197684: first Rte. 639 bridge from Rte. 11, 15 airmi ESE Riverside, 35 airmi ENE Lafayette, 28 June 1963 (19). TU 25885: at 8 mi SW Salem on Rte. 11, 18 June 1962 (3). USNM 194255: Roanoke-Montgomery Co. line, Rt. 11 bridge, 11 September 1956 (7).
South Fork, Roanoke River, Montgomery County.—USNM 194621: bridge off Rte. 11, 1 mi S Elliston, 2.3 mi N Shawsville, near Bench Mark 1282, 12 August 1958 (1). CU 24788: Rte. 11 bridge, 2.4 mi S Elliston, 9 July 1952 (3). CU 24728: about 1 airmi SE Shawsville along Rte. 609. [Figured in detail in Schwartz and Dutcher (1962:370)], 9 July 1952 (2). USNM 194265: same locality, 13 September 1954 (1). USNM 194254: same locality, 2 July 1956 (2). USNM 194622: same locality, 12 August 1958 (1). USNM 177283: same locality, 31 August 1958 (2). USNM 171594: at 2 mi N Alleghany Springs, 22 June 1946 (1). USNM 194623: at 0.75 mi N Alleghany Springs, 2 mi S Shawsville, 16 October 1951 (2).
Tar River Drainage, North Carolina
Tar River or Fishing Creek, Edgecombe County.—USNM 191108: Rte. 1500 bridge about 4.5 mi SW Lawrence, 5.5 mi NNE Tarboro, 19 September 1959 (10). TU 34466: Rte. 44 bridge, 1.9 mi NW Tarboro, 6 September 1964 (8). USNM 40324: at 2 mi below Rocky Mount, 29 August 1888 (2).
Tar River, Nash County.—USNM 191049: railroad bridge just N Rocky Mount, 19 September 1959 (10). TU 34508: Rte. 64 bridge, 7.7 mi NE Pilot, 6 September 1964 (96).
Tar River, Granville County.—UMMZ 181832: Rte. 15 bridge, 7 mi SSW Oxford, 4.5 mi NNE Hester, 30 August 1946 (3). UMMZ 181432:05 mi W Providence, 26 November 1953 (23). CU 19505: at I mi SW Providence (presumed same locality as UMMZ 181432), 30 March 1951 (9).
Neuse River Drainage, North Carolina
Nahunta Swamp Creek, Wayne County.—CU 11892: at 1.2 mi N Pikeville, 27 June 1946 (1).
Contentnea Creek, Wilson County.—USNM 191036: about 3 mi SW Wilson, golf club below Rte. 301, 18 September 1959 (25). DU F-122:4 August 1961 (1).
Falling Creek, Lenoir County.—TU 34439: Rte. 70 bridge, 8.2 mi W Kinston, 5 September 1964 (1).
Little River, Wayne County.—USNM 40386: just W of Goldsboro, 29 August 1888 (6).
Crabtree Creek, Wake County.—UMMZ 161963: Raleigh, 11 October 1929 (2). UMMZ 181430: same locality, 9 May 1930 (3).
Neuse River, Wake County.—USNM 194272: Raleigh, 1890 (2). USNM 40462: below dam at Milburnie, near Raleigh, 27 August 1888 (16). USNM 190975: same locality, 16 September 1959 (4). TU 34532: Rte. 64 bridge at Milburnie, 7 September 1964 (5). USNM 190997: Falls, below bridge, 17 September 1959 (8).
Neuse River, Durham County.—UMMZ 181429: Rte. 15 bridge, 9 mi NE Durham, 29 August 1946 (23).
Eno River, Orange County.—USNM 188555:1.6 mi NE Rte. 70 on Rte. 1567, and 1.1 mi NW on Rte. 1569, 10 May 1964 (30). USNM 188736: same locality, 25 May 1964 (12). DU (unnumbered): below Hillsboro, 18 November 1941 (2).
DISTRIBUTION.—N. raneyi is a central Appalachian, Atlantic slope species with its center of distribution in Virginia. It occurs in the James, Chowan, and Roanoke drainages of Virginia and in the Tar and Neuse drainages of eastern North Carolina (Figure 19). We examined 116 collections from 84 localities in the five drainages. Ecological distribution is discussed in the Ecology section.
It apparently is restricted in the James drainage to a small portion of the upper basin, in Craig and Botetourt counties (Figure 20), and was found downstream on only one occasion. We had extensive collections (182) from the James drainage, in which at least one species of Nocomis was taken from 141 localities scattered throughout the drainage, the majority from the upper half of the basin; more than 3400 Nocomis specimens are involved.
This species probably is continuously distributed, or nearly so, in the 116 rivermile length of the Craig-Johns Creek system (except for its headwaters) since it was taken in 34 collections from 23 localities and was represented in almost every collection made within the middle and lower system; 742 specimens were taken. One collection of four specimens (CU 48533) is from Catawba Creek at 0.4 rivermiles above its mouth where breeding males have also been regularly observed recently. One hybrid N. micropogon × N. raneyi was found in middle Catawba Creek (UMMZ 174826) and another (USNM 194636) in Johns Creek at Newcastle. One specimen (CU 48491) was collected in Pedlar River, Amherst County, 4 rivermiles above its mouth, which is 52 rivermiles downstream from the Catawba Creek mouth. (See discussion of atypical specimens of N. raneyi, pp. 32–36).
The bull chub occurs in the Virginia portion of the Chowan drainage (only six collections) in two of its three main tributary systems, the Nottoway and Meherrin Rivers.
It is widely distributed in the upper montane and upper Piedmont portion of the middle Roanoke drainage. Fifty-one collections from 37 localities were examined. All localities in the upper Roanoke are along the South Fork and upper main channel except for one that is in Back Creek. In the middle basin, populations are present in the Blackwater (Figure 29), Pigg, and Otter Rivers. Its apparent absence from other upper and middle Roanoke tributaries, some rather well collected, is noted in the Ecology section. It has been taken on only three occasions in the Dan River system, the largest southern montane and Piedmont Roanoke tributary.
N. raneyi is widespread in the Tar and Neuse drainages; 24 collections from 21 localities were examined.
Atypical Nocomis raneyi
Specimens that generally agree with our concept of N. raneyi, but which are divergent in certain characters have been collected from the James drainage and are referred to herein as atypical N. raneyi. Atypical specimens were collected mainly between the ranges of two apparently disjunct populations of typical N. raneyi and partially within the interrupted range of N. micropogon in the James (Figure 20). The 13 collections of atypical specimens are from the main James channel and lower portion of all except one of its major tributaries from Craig Creek to 47 miles downriver. The specific localities are given at the end of this discussion. The most upstream locality, in Craig Creek, is 17.5 rivermiles above its mouth, where one atypical tuberculate male, in spawning or just entering postnuptial condition, was captured in 1967 with a typical nuptial male. Sixteen days earlier an apparently eggbound, atypical female was picked up dead at the same locality. Three collections, totaling 47 typical specimens only, were taken in a four year period earlier at the same locality. Typical and atypical specimens were also collected together at the mouth of Craig Creek. In three collections from Craig Creek within 0.5 to 3 miles from its mouth, 32 typical specimens only were taken. The two forms were collected together in one lower Catawba Creek collection and the atypical form was collected alone on three occasions from this stretch of stream including James River about 100 feet above the Catawba mouth. Typical specimens captured outnumbered atypical ones in lower Craig while the opposite was true in lower Catawba. Recent breeding behavioral observations in lower Catawba, however, involve several typical nuptial males and only one atypical (or hybrid?) specimen. The main James has yielded only atypical specimens. The most downstream locality for an atypical specimen is the mouth of Rocky Row Run, which is 11 rivermiles above the mouth of Pedlar River within which a typical specimen of N. raneyi was found. N. micropogon is widespread in the large Maury River system, which enters the James four miles above the Rocky Row Run mouth; N. raneyi is not known from this system.
There are 79 atypical specimens which range from 42 to 229 mm SL, including several prenuptial and postnuptial males and a tuberculate male. Two or three small specimens could not be classified with certainty as atypical or typical N. raneyi.
There are no apparent differences between atypical and typical N. raneyi in the following characters in which typical N. raneyi differs significantly from N. micropogon; circumferential and lateral line scales, vertebral numbers (Table 27), breast squamation, all aspects of body morphometry, size attained, coloration in life and in preservative, and the pharyngeal arches.
Some features in the atypical series generally are somewhat intermediate between typical N. raneyi and N. micropogon. Other characters in which the atypical form differs from N. raneyi are also unlike those of N. micropogon and they are not intermediate between the two species. The main differences between atypical and typical N. raneyi are in certain aspects of tuberculation, involving tubercle numbers, posterior distribution, early development, and size.
In larger juveniles and adults, the numbers are generally intermediate between typical N. raneyi and N. micropogon (Figure 21). The most posterior distribution also is somewhat intermediate between these two forms, ranging in adults from the PIO to AOC lines, more often ending at the AIO line; when extending into and beyond the interorbital area, the tubercles usually are more scattered than in typical N. raneyi. The most posterior tubercles are on or near the dorsal midline, as in typical N. raneyi, rather than dorso-laterally as in N. micropogon. The reduction and scattering of posterior tubercles in the atypical form results in lower tubercle numbers compared with typical N. raneyi. Almost all atypical specimens have tubercle spots and/or buds that are larger than the maximum size of spots and buds in typical N. raneyi and, in many of the former, these structures exceed even the maximum size of those in N. micropogon of similar body length. The spots first appear in smaller atypical specimens than in any species of the micropogon group. The spots of most of the smallest atypical specimens have buds. All young or small juveniles, including females, from 42–62 mm SL, have 7–18 spots or buds. Thus, in small atypical specimens, the pattern of tubercle appearance and their increase is most similar to N. micropogon, but at larger sizes it conforms better to the N. raneyi pattern. Although there is a tubercle reduction in the atypical form, there is no trend toward development of a hiatus between the snout and internasal tubercles, which agrees with N. raneyi and not N. micropogon.
Other characters in which the atypical specimens differ from the species of the micropogon group are discussed below. The snout profile of most young and small juveniles is usually quite rounded, appearing somewhat swollen. The lower caudal fin lobe is considerably shortened and more rounded. The anterior rays of the anal fin are often reduced in length, resulting in a smaller fin with a broadly convex margin. The paired fins are frequently shorter and more broadly rounded.
The following factors are considered in an attempt to determine the origin and significance of the atypical specimens: (1) distribution and relative abundance with regard to opportunity for intergradation or interspecific hybridization between N. micropogon and N. raneyi; (2) atypical N. raneyi morphology in relation to that of Nocomis intergrades and hybrids; and (3) possible influence(s) by environmental disturbance.
Almost all atypical specimens were taken from an area connecting the two main populations of N. micropogon (one above Craig system, one from Maury system downstream) and the main typical N. raneyi population (Craig Creek area). The range of the atypical specimens may thus be one in which the forms met and freely interbred in the past. However, the presence of typical N. raneyi below the atypical area (known from one specimen from Pedlar River), and the occurrence of N. micropogon with typical N. raneyi in the Craig and Catawba systems are difficult to explain by intergradation, particularly since N. raneyi probably entered the James drainage in the Craig Creek area (see Dispersal section, p. 70). Relative rarity of one parental species is frequently cited as an important factor in production of hybrids. Although N. micropogon is unknown from the James River section with atypical N. raneyi and the lower portion of most tributaries of this section, these larger waters have not been well collected. Even if N. micropogon is present but rare in this section, the abundance of atypical specimens and small numbers of typical N. raneyi (only in a small portion of the section) is not explained by hybridization within the section.
The atypical specimens conform to N. raneyi in most diagnostic characters; in the others they are roughly intermediate between N. micropogon and typical N. raneyi or differ from both species. The atypical form does not agree with the concept of an intergrade population, variably intermediate in most or all diagnostic characters (as we have found in subspecific intergrades of N. leptocephalus and populations of N. micropogon that show effects of apparent introgressive hybridization with N. platyrhynchus). Interspecific hybrids are generally intermediate but may deviate to the extent that they are extreme in certain characters, thus not excluding atypical N. raneyi from this category.
James River water is very darkly colored, due to the effluent from a large pulp mill at Covington, Virginia, downstream through the upper half or more of the atypical N. raneyi section. The peculiar morphology of the atypical N. raneyi may be induced by pollution. Indirect evidence from local anglers indicates that N. raneyi spawn in the main channel of the James. It would then be in direct contact with pollution beginning at early developmental stages. Lindsey (1956:770) gave evidence that fin shape in certain Canadian populations of Couesius plumbeus may be influenced by environmental conditions. De Sylva, Kalber, and Shuster (1962:29) noted deformed fins in striped bass collected in proximity to a chemical plant. Many cyprinid fishes with malformed mouths and fins were found by Larimore and Smith (1963:353) near a pollution source in an Illinois stream. Beadles (1966) concluded that industrial and domestic effluents could have produced variations in meristic and morphometric characteristics of subpopulations of three cyprinid species in an Oklahoma stream. Additional literature treating morphological variations caused by environmental conditions in fishes was summarized by Barlow (1961).
It is more probable that the atypical condition of N. raneyi is due to its development in polluted waters rather than to other alternatives treated. Solution of this problem must include additional collections, observations, and experimental work.
MATERIAL EXAMINED.—Atypical N. raneyi from the James drainage, Virginia. Included are museum numbers and number of specimens of typical N. raneyi taken with three of these series. Collections are listed in progressive downstream order; following the collection date is the number of specimens captured (in parentheses).
Botetourt County.—USNM 201895: Craig Cr. at jet. Rtes. 614–683, 7.5 airmi W. Eagle Rock, 20 May 1967 (1). USNM 201898: same locality at USNM 201895, 6 June 1967 (1); taken with one typical specimen, USNM 201897. CU 50596: Craig Cr. at mouth, James River, 30 and 31 March 1965 (3); taken with two typical specimens, CU 48427. CU 52208: James R. at Eagle Rock, about 0.5 mi downstream Craig Cr. mouth, 1966 after 1 June (14). CU 47586: James R. about 100–200 ft. above mouth Catawba Cr., 24 October 1964 (15). CU 47568: Catawba Cr. 0.2 mi above mouth, 24 October 1964 (3). CU 52597: Catawba Cr. 0.4 mi above mouth, 10 May 1965 (6) taken with four typical specimens, CU 48533. CU 50820: same locality as CU 52597 (1). TU 25858: James R. at Springwood, 18 June 1962 (10). CU 47587: same locality as TU 25858, 23 October 1964 (10). CU 48438: Looney Cr. 0.3 mi above mouth, 30 March 1965 (3). CU 48426: James R. at mouth Jennings Cr., 29 March 1965 (11).
Amherst County—CU 48549: Rocky Row Run at mouth, James R., at Snowden, 10 airmi S Buena Vista, 9 May 1965 (1).
PROBLEMATIC SPECIMENS FROM THE CRAIG CREEK AREA.—Craig Creek, Catawba Creek, and the James River near their mouths, all part of the James drainage, is one of the most critical areas in this study, for conclusions on the status of the forms of the micropogon group have been based on specimens found in this drainage area. Since some of the series from this area include small, poorly preserved, and difficult to identify specimens of apparent hybrids, and typical and atypical specimens, a discussion of our methods (some subjective) used to identify these and other series is warranted. These collections also assume considerable importance due to a recent impoundment of a section of the Johns Creek system, the proposed impoundment of much of Craig Creek (Mussey, 1948:20), and channelization of the lower 17 miles of Johns Creek. This is the only area in which three species of Nocomis have been collected together.
No adult N. micropogon were available from the Craig area. However, juvenile N. micropogon were taken from upper Johns Creek (TU 25469, 6 specimens), upper Craig Creek (UMMZ 135413, 2 specimens), and upper Catawba Creek (CU 50610, 1 specimen). These have the tubercle pattern of adult N. micropogon well developed or incipient and their meristic (Table 27) and morphometric values are well within the ranges of N. micropogon. Also clearly determined are three specimens (UMMZ 135401) taken with one N. raneyi (UMMZ 181830) from middle Johns Creek. The three range from 60–80 mm SL and have the juvenile tubercle pattern, low meristic values, long snout and larger mouth of N. micropogon. The specimen identified as N. raneyi lacks tubercle spots (as expected for this species at 60 mm SL but not for N. micropogon), has 35 circumferential scales, 41 vertebrae, and, in coloration and morphometry, resembles N. raneyi.
The species were taken together on two other occasions from the lower half of Johns Creek. The most upstream collection, was 1.5 miles east of Craig Healing Springs and consisted of two specimens (CU 50340, 36 mm SL; and CU 52598, 42 mm SL). Both are too small to be identified by tubercle spots and morphometry, although CU 52598 has a rather long snout, like N. micropogon. The snout of the other specimen is more like N. raneyi. The apparent N. micropogon specimen has 30 circumferential scales; no N. raneyi was found with 30 circumferential scales and a 31 count is rare. Its vertebrae number 41, which is occasional for N. micropogon but typical for N. raneyi; the lateral line count of 40 applies to both species. Thus CU 52598 is identified as, probably, N. micropogon. CU 50340 is identified as, probably, N. raneyi from its appearance and vertebral count of 42; we have not found a vertebral count of 42 in N. micropogon over its range. The circumferencial count of 32 and lateral line of 40 are common to both species.
The other collection from Johns Creek, at 4.2 roadmiles on Rte. 311 from Newcastle, includes seven N. raneyi (CU 50422), 37–116 mm SL, one N. micropogon (CU 50423), 39 mm SL, and several N. leptocephalus. The 39 mm specimen has more heavily pigmented scale margins, a longer snout than the other young specimens, 30 circumferential scales, and 40 vertebrae, thus apparently representing N. micropogon. One specimen with tubercle development, 116 mm SL, shows the typical juvenile pattern of N. raneyi. The other six specimens apparently are young N. raneyi based on scale counts, and vertebrae of 41 (2), 42 (3), and 43 (1).
All except one specimen from Craig Creek, near its mouth, and the James River in the immediate vicinity are typical or atypical N. raneyi. The exception, a specimen (CU 47584), 65 mm SL, lacks tubercle spots, has 41 vertebrae, 40 lateral line scales, and 30 circumferential scales. The circumferential count falls out of the range of N. raneyi. The gape width of 6.8 percent SL and snout length of 8.5 percent SL is intermediate between N. micropogon and N. raneyi. It is tentatively identified as N. micropogon.
The nearest locality upriver (USNM 132064 taken around 1880) is in lower Mill Creek, a James River tributary about five miles above the mouth of Craig Creek. The 14 specimens are very poorly preserved and small, 45–80 mm SL. The unsealed breasts and the unwhorled intestines exclude these being N. leptocephalus. They are identified as N. micropogon mainly by the meristic values: circumferential scales 29 (1), 30 (5), 31 (5), 32 (2); lateral line scales 38 (3), 39 (8), 40 (2); total vertebrae 39 (6), 40 (7), 41 (1). The tubercle spot pattern, typical of juvenile N. micropogon, was discernible only in the largest specimen.
The characters of atypical specimens, but basically N. raneyi, from lower Craig and Catawba Creeks and the James River are given above. We found two specimens from the Craig Creek area, one from lower Johns Creek and one from middle Catawba Creek, that do not fit our concept of the atypical specimens, but rather, are intermediate between N. micropogon and N. raneyi in most of the diagnostic characters. These have been determined as hybrids between the two species. We have not found atypical specimens from the vicinities in which these specimens were taken. They will be described in paper 5 on hybridization (p. 2).
- الاقتباس الببليوغرافي
- Lachner, Ernest A. and Jenkins, Robert E. 1971. "Systematics, distribution, and evolution of the chub genus Nocomis Girard (Pisces, Cyprinidae) of eastern United States, with descriptions of new species." Smithsonian Contributions to Zoology. 1-97. https://doi.org/10.5479/si.00810282.85
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