Orconectes alabamensis

Orconectes (Gremicambarus) alabamensis (Faxon)

Cambarus Alabamensis Faxon 1884:125; 1885a:104, pl. 4: fig. 4, pl. 10: figs. 3, 3′, 3a, 3a′.

Cambarus alabamensis.—Hay, 1899b:960.

Cambarus (Faxonius) alabamensis.—Ortmann, 1905c:112.

Faxonius alabamensis.—Creaser, 1933a:3 [by implication]; 1962:2 [by implication].

Faxonius (Faxonius) alabamensis.—Creaser, 1933b:16 [by implication].

Orconectes alabamensis.—Hobbs, 1942a:352 [by implication]; 1974b:26, fig. 166.—Fitzpatrick, 1963:61 [by implication].—Cooper and Hobbs, 1980:2, figs. 1, 2a.

Orconectes (Orconectes) alabamensis.—Hobbs, 1942b:154 [by implication].

Orconectes (Gremicambarus) alabamensis.—Fitzpatrick, 1987a:54.

TYPES.—Syntypes, USNM 4876 (14 male I, 16 female, 4 male II), MCZ 3565 (2 male I, 2 female, 2 male II.

TYPE LOCALITY.—Second Creek, Waterloo, Lauderdale County, Alabama.

RANGE.—Tennessee River basin from Shoal Creek in Lawrence County, Tennessee, and Lauderdale County, Alabama, to Hardin County, Tennessee.

Orconectes alabamensis (Faxon)

Cambarus Alabamensis Faxon, 1884:124, 125–127, 146; 1885a: 85, 86, 102, 104–105, 161, 168, 174, 178, pl. IV: fig. 4; pl. X: fig. 3, 3′, 3a, 3a′; 1885b:359.—Underwood, 1886:366. Cambarus alabamensis.—Hay, 1899:960, 962.—Ortmann, 1902:278; 1905:110, 112, 117, 127; 1931:90, 91–93.—Steele, 1902:7.—Harris, 1903:60, 70, 137, 146.—Faxon, 1914:383, 420.

Cambarus (Faxonius) alabamensis.—Ortmann, 1905:112.

Faxonius alabamensis.—Creaser, 1933a:3 [by implication]; 1933b:16; 1962:2 [by implication].

Faxonius (Faxonius) alabamensis.—Creaser, 1933b:21 [by implication].

Orconectes alabamensis.—Hobbs, 1942a:352 [by implication]; 1968:K12, K31, fig. 31h; 1972:89, 148, figs. 70f, 71d; 1974: 26, fig. 166.—Hart and Hart, 1974:75, 90.—Bouchard, 1976b:14.—Fitzpatrick, 1976:56.—Hobbs and Walton, 1977:602.

Orconectes (Orconectes) alabamensis.—Hobbs, 1942b:154 [by implication]; 1959:894.

DIAGNOSIS.—Body and eyes with pigment. Rostrum with median carina and marginal tubercles present at base of acumen. Areola 3.6 to 6.4 times as long as wide and comprising 26.4 to 31.9 percent of entire length of carapace (34.7 to 41.1 percent of postorbital carapace length) with 4 to 7 punctations in narrowest part. Cervical spine small but well developed; suborbital angle vestigial; postorbital ridge well developed with small acute spines or tubercles cephalically. Antennal scale approximately 2.5 times as long as wide, broadest at or slightly distal to midlength. Chela with palm inflated, bearing row of about 7 squamous tubercles on mesial surface; fingers gaping, and mesial margin of dactyl with vestigial adpressed tubercles; opposable margin of dactyl not excised. Hook on ischium of third pereiopod of male. First pleopod of first form male without angular shoulder on cephalic surface, distal three-fifths inclined caudally, terminal elements with distal portions recurved and central projection reaching cephalic margin of coxa of second pleopod when abdomen flexed; pleopod length divisible into carapace length 2.7 to 3.0 (average 2.9) times; terminal elements slender, subparallel; central projection constituting 30.6 to 33.5 (average 31.7) percent of total length of pleopod, bladelike, tapering to apex, and not extending so far caudally as mesial process; mesial process subcylindrical in section proximally, troughlike distally. Annulus ventralis as figured. First pleopod present in female.

SYNTYPIC MALE, FORM I.—Body and eyes pigmented. Cephalothorax (Figure 1a,i) subovate in section; abdomen narrower than carapace (10.9 and 11.6 mm), width of latter greater than depth in caudodorsal margin of cervical groove (11.6 and 10.2 mm). Areola broad, 4.4 times as long as wide, with 6 punctations across narrowest part, length 29.7 percent of entire length of carapace (38.2 percent of postorbital carapace length). Rostrum with margins not thickened, slightly elevated and gently converging to marginal tubercles; acumen reaching slightly beyond ultimate podomere of antennular peduncle; upper surface of rostrum with low carina cephalically, basal portion weakly excavate and thickly set with punctations. Subrostral ridge weakly developed, evident in dorsal aspect along basal half of rostrum. Postorbital ridge moderately strong, grooved dorsolaterally, and terminating cephalically in small tubercle. Suborbital angle vestigial, broadly rounded. Cervical spine small but well defined. Branchiostegal spine well developed. Carapace densely punctate except cephaloventrally where punctations replaced by granulations. Abdomen longer than carapace (28.0 and 23.5 mm); pleura truncate ventrally, and with rounded caudoventral extremities; cephalic section of telson with 2 spines in each caudolateral corner. Proximal podomere of uropod with spine on each lobe, that on lateral one small; both rami with median keel, that on mesial ramus terminating in premarginal spine.

Cephalic lobe of epistome (Figure 1g), with prominent cephalodorsally directed cephalomedian projection, set off from main body of epistome by contracted base; cephalolateral margins rounded, slightly elevated; main body of epistome with prominent fovea; epistomal zygoma broadly arched. Basal segment of antennule with spine on ventral surface slightly distal to midlength. Antennal peduncle with spine on lateral surface of basis and on ischium. Antenna reaching tergum of second abdominal segment. Antennal scale (Figure 1l) 2.5 times as long as broad, broadest at about midlength; mesial border of lamella evenly rounded except for weak hump distomesially; apical spine slightly overreaching antennular peduncle. Ventral surface of ischium of third maxilliped clothed in plumose setae; distolateral angle of podomere acute.

Right chela (Figure 1j) with palm inflated (ratio of depth to width 0.70), lacking lateral costa, shorter than carapace (18.5 and 23.5 mm), and 2.3 times as long as wide; thickness slightly more than two-thirds length of areola and little more than four-fifths length of mesial margin of palm, latter with 3 rows of small to vestigial tubercles: 8 in ventralmost, 7 in middle, and 6 in dorsal row (left chela with 5, 6, and 7, respectively); remainder of chela punctate, lacking tubercles except on opposable margins of fingers. Latter slightly gaping basally. Opposable surface of fixed finger with conspicuous tuft of plumose setae along basal half, denser ventrally than dorsally, margin with row of 9 tubercles along proximal two-thirds, and band of minute denticles extending from fifth tubercle to base of corneous tip of finger; dorsal and ventral surfaces with well-defined submedian longitudinal ridge flanked by setiferous punctations; setae on proximomesial side of ventral ridge contributing to setal tuft at base of finger; lateral margin of finger rounded with weak longitudinal ridge. Opposable margin of dactyl with row of 9 low rounded corneous tubercles along proximal two-thirds and band of minute denticles extending from fifth tubercle to corneous tip of finger; dorsal and ventral surfaces of finger with submedian longitudinal ridge; mesial surface with row of vestigial, strongly adpressed tubercles proximally giving way to setiferous punctations distally. Carpus 1.4 times as long as broad, with shallow groove dorsally, groove with angle at base of distal fourth; dorsal and lateral surfaces punctate; mesial surface with prominent procurved spine and 2 large tubercles proximal to it; ventral surface punctate except for acute spine on lateral articular condyle. Dorsal surface of merus with 2 premarginal tubercles one of which spiniform; lateral and mesial surfaces largely polished and sparsely punctate; ventral surface with only 1 spiniform tubercle representing lateral row and 11 spiniform ones constituting mesial row; distolateral apophysis with spiniform tubercle. Ventromesial margin of ischium of cheliped with 1 tubercle.

Ischium of third pereiopod (Figure 1h) with simple hook overreaching basioischial articulation, not opposed by tubercle on basis. Ventral membrane on coxa of fifth pereiopod studded with short setae.

First pleopods (Figure 1b,f,k) symmetrical and reaching second pereiopod when abdomen flexed. (See “Diagnosis” for description.)

SYNTYPIC FEMALE.—Differing from male, form I, in following respects: width of abdomen subequal to that of carapace (12.9 and 12.8 mm); fovea on epistome not nearly so prominent; ratio of depth to width of chela 0.66; palm of chela less inflated, mesial surface with 7 tubercles in ventralmost row, 7 in middle, and 6 in dorsal (left chela with 6, 7, and 5, respectively); fingers not conspicuously gaping; mesial surface of carpus with 3 tubercles proximal to major spine; dorsal surface of merus with 2 premarginal spiniform tubercles, ventrolateral row of tubercles represented by 1 well-developed spiniform tubercle and 2 or 3 vestigial ones, ventromesial row consisting of 10 (left with 12) subspiniform to spiniform tubercles. (See Table 1.)

Annulus ventralis (Figure 1d) firmly, but not inflexibly, fused to sternum, subrectangular in outline and about 1.7 times as broad as long. Cephalic half with median trough narrow and reaching submedian fossa slightly cephalic to level of maximum width; digitiform tongue arched caudosinistrally; sinus in form of tilted reversed S, its caudal extremity situated on midline of caudal wall. Postannular sclerite approximately 3 times as broad as long, about three-fourths width of annulus, and approximately two-fifths as long. First pleopod extending cephalically to midlength of annulus when abdomen flexed.

SYNTYPIC MALE, FORM II.—Differing from male, form I, in following respects: areola with punctations more sparsely distributed, 5 across narrowest part; antenna reaching tergum of fifth abdominal segment; palm of chela less inflated, ratio of depth to width 0.69; mesial surface of palm with 5 tubercles in ventralmost row, 7 in middle, and 6 in dorsal (left chela with 4, 7, and 5, respectively); fingers not conspicuously gaping; hook on ischium of third pereiopod greatly reduced. (See Table 1.)

First pleopod (Figure 1c,e) reaching coxa of second pereiopod, conspicuously less deeply cleft than in first form male, terminal elements shorter and more robust, and central projection less acute.

COLOR

Orconectes alabamensis (Faxon)

Cambarus Alabamensis Faxon, 1884:125; 1885a:104, pl. 4: fig. 4; pl. 10: figs. 3, 3′, 3a, 3a′.

Cambarus alabamensis.—Hay, 1899b:960.

Cambarus (Faxonius) alabamensis.—Ortmann, 1905c: 112.

Faxonius alabamensis.—Creaser, 1933a:3 [by implication]; 1962:2 [by implication].

Faxonius (Faxonius) alabamensis.—Creaser, 1933b: 16 [by implication].

Orconectes alabamensis.—Hobbs, 1942a:352 [by implication].—Fitzpatrick, 1963:61 [by implication].

Orconectes (Orconectes) alabamensis.—Hobbs, 1942b: 154 [by implication].

TYPES.—Syntypes, USNM 4876 (14 I, 16 , 4 II), MCZ 3565 (2 I, 2, 2 II).

TYPE-LOCALITY.—Second Creek, Waterloo, Lauderdale County, Alabama.

RANGE.—Known only from tributaries of the Tennessee River along the Alabama-Tennessee-Mississippi border.

HABITAT.—Streams.

Faxonius alabamensis, the Alabama crayfish, is a species of freshwater crayfish that lives in Alabama, Mississippi and Tennessee.

Orconectes alabamensis eller «Alabama crayfish» er en art av ferskvannskreps innenfor slekten Orconectes (familie Cambaridae, orden Reptantia) som inngår i den store gruppen av såkalte tifotkreps. Dette er ferskvannskreps som på engelsk oftest kalles «crayfish».

Orconectes alabamensis er en av de om lag 85 artene i slekten, og har en utbredelse med forekomster i elver og innsjøer nesten utelukkende i Alabama, Mississippi og Tennessee.