Propagurus gaudichaudii (H. Milne Edwards 1836)

"Shield varying from slightly broader than long to slightly longer than broad. Rostrum roundly sub-triangular, subacute, sometimes produced beyond level of lateral projections; with or without terminal spine. Lateral projections broadly triangular or rounded, with or without submarginal spine. Ocular peduncles slightly more than half to approximately 0.75 length of shield; broader at base of corneas than proximally; corneas slightly dilated. Ocular acicles ovately or roundly triangular, dorsal surfaces somewhat concave, each with strong, sometimes comeous-tipped submarginal spine. Antennular peduncles overreach distal margins of corneas by 0.50-0.65 length of ultimate segment; basal segment with strong spine on lateral surface in distal half. Antennal peduncles overreach distal margins of corneas by 0.15-0.35 length of ultimate segment; second segment with laterodistal angle reaching to or beyond distal margin of fourth peduncular segment, with simple or bifid terminal spine, mesial margin with 4-7 corneous-tipped spines, lateral margin with few tufts of setae, dorsomesial distal angle with small corneous-tipped spine; first segment sometimes with spine on distolateral margin dorsally; ventrolateral margin with 1 small spine. Antennal acicles reaching to or beyond distal margins of corneas, each with strong terminal spine and numerous tufts of long stiff setae on mesial face.

External enopodal lobe of maxillule rudimentary. Maxilla with broad scaphognathite. First maxilliped with short, distally twisted endopod. Second maxilliped with basis-ischium fusion incomplete. Meri of third maxillipeds each with dorsodistal spine, ventral margins unarmed.

Right cheliped considerably stronger than left, but not appreciably longer; with weak hiatus between dactyl and fixed finger. Dactyl with double row of corneous-tipped spines on dorsal surface laterad of midline, at least proximally and double row of tufts of stiff setae; dorsomesial margin with row of small corneous-tipped spines, becoming more prominent distally. Palm with row of strong corneous-tipped spines on dorsomesial margin, convex dorsal surface with 6 rows of conical corneous-tipped spines; dorsolateral margin not distinctly delimited proximally, but with irregular row of corneous-tipped spines becoming marginal and extending nearly to tip of fixed finger; lateral face of palm with few spines or tubercles dorsally; mesial face with transverse rows of tubercles. Carpus with irregular row of strong corneous-tipped spines on dorsomesial margin, dorsal surface with irregular rows of corneous-tipped spines accompanied by sparse tufts of stiff setae; dorsolateral margin not distinctly delimited, but with row of corneous-tipped spines; lateral face primarily with tufts of stiff setae. Merus with 2-4 strong and 1 or 2 smaller spines on dorsodistal margin, dorsal margin with short transverse ridges and quite short stiff setae, distal-most ridge spinose; ventromesial margin with row of small spines distally replaced by short transverse row of tuberculate spines proximally; ventrolateral margin with row of corneous-tipped spines distally replaced by low protuberances proximally; ventral surface with 2 transverse rows of conical spines, largest proximally.

Left cheliped with two irregular rows of corneous-tipped spines on dorsal surface of dactyl proximally becoming single row distally, dorsomesial margin and mesial face with irregular rows of tuberculate corneous-tipped spines, more numerous in proximal half. Palm with irregular row of strong corneous-tipped spines on dorsomesial margin, dorsal surface generally somewhat flattened, with 4 irregular rows of tuberculate corneous-tipped spines decreasing to 2 rows on fixed finger; dorsolateral margin not clearly delimited but with double row of tuberculate or corneous-tipped spines. Carpus with 1 prominent spine on dorsodistal margin; dorsomesial margin with strong corneous-tipped spines and tufts of stiff setae, dorsal surface with adjacent and median rows of corneous-tipped spines, interspersed with few smaller pines: dorsal surface laterad of midline with irregular rows of corneous-tipped spines extending onto lateral face dorsally. Merus with 1-3 large and 1 or 2 smaller spines on dorsodistal margin, dorsal margin with transverse ridges and setae, distal-most spinose: ventromesial margin usually with short row of corneous-tipped spines in distal half, becoming low tubercles proximally and extending onto ventral surface; ventrolateral margin with row of prominent spines in distal half, shifting onto ventral surface proximally, 1 larger tuberculate spine at proximal angle.

Ambulatory legs overreaching chelipeds by approximately half length of dactyls. Dactyls of left and right similar: moderately long and stout, 1.652.0 length of propodi; in dorsal view slightly twisted; in lateral view slightly curved; dorsal surfaces somewhat flattened, each with double row of corneous-tipped spines and row of stiff setae, inner-most row becoming simple corneous spines distally; lateral and mesial surfaces each with longitudinal sulcus, strongest on second; lateral faces each also with row of tufts of stiff setae, and arc of 4 or 5 stiff setae proximally, mesial faces each also with row of stiff setae proximally and arc of stiff setae distally; ventral margins each with row of 4 or 5 prominent corneous spines distally, becoming very small widely-spaced spinules in proximal 0.75. Propodi each with 2-4 rows of strong corneous-tipped spines accompanied by tufts of stiff setae extending onto lateral face dorsally; mesial faces each with 1 or 2 blunt or subacute spines dorsally and tufts of stiff setae; ventrodistal margin with row of small corneous spinules or short stiff bristles. Carpi each with row of strong corneous-tipped spines on dorsal surface; lateral faces spinulose (second) or with low protuberances and tufts of stiff setae (third). Meri all with transverse rows of short stiff setae dorsally, ventral margins of second pereopods each with 1 or 2 spines; 7entral margins of third unarmed. Sternite of third pereopods with row of setae on roundly subrectangular to subquadrate anerior lobe.

Telson with asymmetrical posterior lobes separated by slender median cleft; terminal margins often considerably produced laterally, each with row of small calcareous spines on inner half, calcified but unarmed on outer half.

Color: Beautiful violet (Boschi et al. 1992).

Distribution: Chile, Strait of Magellan, Airgentina, Uruguay; littoral to 150 m.

Remarks

The holotype of Pagurus gaudichaudii has the abdomen and all appendages disarticulated; the fourth and fifth pereopods, including their coxae, are missing. The specimen is determined to be a male since no gonopores are present on the coxae of the third pereopods. The bottle contains two labels, an old printed one reading "Pagurus Gaudichaudii Edw., M. Gaudichaud, Valparaiso," and a second hand written by Bouvier indicating the reference to Milne Edwards' publication and the mention of "type." The holotype of Pagurus barbiger, as noted by Forest & de Saint Laurent (1968) is a young female. Its label indicates "Eupagurus (Bernhardus) barbiger M. Edw. et Mocquet, 1891, Mission du Cap Horn, baie Orange, 22m." The bottle, MNHN Pg 2401, also contains a second smaller female (sl = 5 mm), which is not mentioned in the original publication, and therefore cannot be considered a type specimen.

Benedict (1901) noted that A. Milne Edwards' (1891) description of Pagurus barbiger had come to his attention only after his own description of Pagurus patagoniensis (as Eupagurus) had been published (Benedict 1892). Based on A. Milne Edwards (1891) description and figures, Benedict (1901) pointed out several differences between P. barbiger and P. patagoniensis, but acknowledged that these differences might well be related to size and that the two might prove to be conspecific. Lagerberg (1905) formally placed P. patagoniensis in synonymy. Haig (1955) recognized the similarities between P. barbiger as described by Lagerberg (1905) and P. gaudichaudii (as P. gaudichaudi) from Chile. At Haig's request, J. Forest examined the types of both species and confirmed her suspicions. Pagurus barbiger, together with P. patagoniensis were then placed in synonymy with P. gaudichaudii; however, neither Lagerberg (1905) nor Haig (1955) actually examined Benedict's (1892) P. patagoniensis. We have now compared Ben-edict's syntypes with the holotypes of P. gaudichaudii and P. barbiger, as well as with specimens of P. gaudichaudii from Calypso station 170 off Rio de la Plata, and can reaffirm the conspecificity of the three taxa.

Forest & de Saint Laurent (1968) discussed the size-related variations observed in small specimens of P. gaudichaudii. These include longer ocular peduncles, narrower ocular acicles, shorter antennular and antennal peduncles, and stouter ambulatory legs. Propagurus gaudichaudii differs from the other species of the genus in several morphological attributes: the dorsal surface of the chela of the left cheliped is flattened, lacking the elevated median row(s) of spines of the other species; the carpus of the left cheliped is appreciably broader and, while armed with numerous spines, these do not form the two distinctive longitudinal rows seen in the other species; the ambulatory dactyls have only a few strong corneous spines distally, followed by widely-spaced very tiny spinules, whereas the dactyls of all three other species are each armed with a complete row of strong spines; the dorsal surfaces of the propodi of the ambulatory legs are generally flattened and each is armed with a double row of spines. In these characters, P. gaudichaudii approaches species of the bernhardus group of Pagurus (cf. McLaughlin 1974), which is undoubtedly why Benedict (1901) aligned P. patagoniensis with species like Pagurus bernhardus (Linnaeus 1758).

In addition to the differentiating characers of the gills, the short ocular peduncles, spinose laterodistal projections of the second segment of the antennal peduncle, and spatulate pleopodal endopods clearly unite Propagurus gaudichaudii with the other species assigned to the genus. The distincive subquadrate shield and general shape of the posterior telsonal lobes of P. gaudichaudii appear to indicate a closer relationship to P. deprofundis than to either P. haigae or P. yokoyai. Although the shield is nore angular in P. gaudichaudii than in P. deprofundis, both are somewhat dissimilar to the more rounded shields of P. haigae and P. yokoyai. In both P. gaudichaudii and P. deprofundis there is a tendency for the terminal margins of the telson to be produced laterally; however, while in P. gauiichaudii the lateral half of each lobe usually consists of a pectinate, faintly denticulate, or entire plate, this portion in P. deprofundis, like the median portions in both species, is often provided with spines. In P. gaudichaudii, the mesial faces of the palms of the chelipeds are armed with transverse rows of tubercles, not identical with, but similar to the rows of tubercles or small spines seen on the lateral surfaces of the palms of P. deprofundis. No comparable armature is seen on either surface of the palms of P. haigae or P. yokoyai." (McLaughlin and St. Laurent, 1998)