Comprehensive Description

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Description

MATERIAL EXAMINED. — Eastern Pacific. "Challenger", stn 300, W of Valparaiso, Chile, 33°42'S, 78°18'W, 2515 m, 17.12.1875: ♂ 14.9 mm , holotype (NHM 1888:33), 5 ♂ 11.8-13.3 mm, 1 ♀ 7.8 mm, 2 ov. ♀ 8.1, 11.4 mm , paratypes (NHM 1888:33). — Stn 3374, Galapagos Islands, 2°35'N, 83°53'W, 3334 m, 3.03.1891: 1 ov. ♀ 6.3 mm (USNM 42625). — Stn 4647, off Peril, 4°33'S, 87°42'30"W, 3667 m, 9.11.1904: 10 ♂ 5.9-10.0 mm, 6 ♀ 5.1-7.0 mm (USNM 276114); 2 ♂ 8.8, 9.4 mm, 2 ov. ♀ 5.7, 6.0 mm (MNHN-Pg 5649).

 

"Challenger". Chile. Juan Fernandez Island, [no stn number], 2115 m: 1 ♂ 13.3 mm, 3 ov. ♀ 10.0-10.4 mm (USNM 15298). — Off Juan Fernandez Island, [no stn number], 2115 m: 3 ♂ 8.5-12.8 mm (ZMK). — Off Valparaiso, [no stn number or other data]: 1 ♀ 11.2 mm, 1 ov. ♀ 10.7 mm (USNM 156411).

 

Central Pacific. Magellan Rise. POSSE EXPEDITION, "Alvin", dive 1816, 7°00'N, 177°00'W, 3150 m, 17.03.1987, coll. K. SMITH: 1 ♂ 12.2 mm (SIO C9941).

 

TYPES. — Holotype : 14.9 mm (Holotype of Parapagurus abyssorum Henderson, 1888), "Challenger", stn 300, W of Valparaiso, Chile, 33°42'S, 78°18'W, 2515 m, 17.12.1875 (NHM 1888:33). Paratypes: 5 11.8­13.3 mm, 1 ♀ 7.8 mm, 2 ov. ♀ 8.1, 11.4 mm, same data as holotype (NHM 1888:33).

 

REDESCRIPTION. — Shield about as long as broad; dorsal surface usually well calcified, with scattered short setae; anterior margin weakly concave; lateral projections broadly rounded; anterolateral margin sloping. Rostrum broadly subtriangular, rounded distally, overreaching lateral projections; often with inconspicuous low mid-dorsal ridge. Anterodistal margin of branchiostegite unarmed, setose.

 

Ocular peduncles (including corneae) distinctly less than half length of shield, each with rows of setae dorsally; peduncles inflated basally, slightly constricted medially. Ocular acicles subtriangular, terminating in strong simple spine; separated basally by slightly less than basal width of one acicle.

 

Antennular peduncles slender, long, exceeding distal margins of corneae by 0.8 or more length of penultimate segments. Ultimate and penultimate segments with scattered setae. Ultimate segment nearly twice as long as penultimate. Basal segment with ventromesial distal spine; mesial face unarmed; lateral face with statocyst lobe having subrectangular distal lobe armed with 1-3 small spines, and 1 spine proximally.

 

Antennal peduncles exceeding distal margins of cornea by about 0.8 or more length of fifth segments. Fifth segment with scattered setae on lateral and mesial margins. Fourth segment with scattered setae. Third segment with strong ventromesial distal spine. Second segment with dorsolateral distal angle produced, terminating in strong multifid spine; mesial margin with spine on dorsodistal angle. First segment unarmed on lateral face; ventromesial angle produced, with row of small spines. Antenna] acicles weakly curved in dorsal view, setose; exceeding distal margin of cornea by about half or less length of acicle; mesial margin armed usually with 4 to 8 (range 1 to 10) small spines. Flagellum distinctly overreaching extended right cheliped, with sparse short setae less than 1 flagellar articles in length.

 

Mandible, maxilla, and first and second maxillipeds typical of species in genus. Maxillule with external lobe of endopod weakly developed, internal lobe with long terminal seta and 4 subterminal setae. Third maxilliped with crista dentata consisting of about 19 corneous-tipped teeth. Sternite of third maxilliped with spine on each side of midline. Epistomial spine usually present.

 

Chelipeds markedly dissimilar, each with dorsal surfaces of carpus and chela covered with moderately dense setation; proportions of carpus and chela influenced by size and sexual dimorphism (see Variations). Right cheliped with fingers bent inwards at tips, each terminating in small corneous claw; with tufts of setae on dorsal and ventral surfaces; cutting edges each with irregularly-sized calcareous teeth; cutting edge of dactyl also with distal row of small, closely-set, corneous teeth. Dactyl set at oblique angle to palm, with dorsomesial and mesial rows of small spines proximally. Palm and carpus each with numerous small spines and tubercles on dorsal and ventral surfaces (spines and tubercles usually less numerous on ventral surfaces). Merus with small tubercles on dorsal, dorsolateral and ventral surfaces; mesial surface smooth, with ventromesial row of spines. Ischium with dorsal and ventromesial row of spines. Coxa with 1 or 2 spines on ventrodistal margin and ventromesial row of setae.

 

Left cheliped slender. Fingers each terminating in small corneous claw; dorsal and ventral surfaces with scattered tufts of short setae; cutting edge of dactyl with row of minute, closely-set, corneous teeth distally; cutting edge of fixed finger with row of regularly-spaced, small, evenly-sized calcareous teeth. Palm with dorsomesial row of small spines; dorsolateral face with small spines. Carpus with irregular rows of small spines dorsally; lateral face with scattered small spines or tubercles. Merus with row of short, stiff setae dorsally; ventromesial margin with row of spines. Ischium armed with blunt spine or tubercles dorsally, and ventromesial row of spines. Coxa usually with 2 small spines on ventrodistal margin, and ventromesial row of setae.

 

Ambulatory legs similar from right to left (except slightly longer segments on right), slender, long, distinctly overreaching right cheliped. Dactyl 1.3 to 1.5 times as long as propodus; with dorsal and ventromesial distal row of setae; ventromesial margin with row of about 8 or more minute corneous spinules. Merus, carpus, and propodus each with short stiff setae on dorsal margin (setae on propodus usually arranged in short transverse rows). Propodus 6 or more times as long as high. Carpus with dorsodistal spine. Merus of first ambulatory leg about 4.5 times as long as high; with longitudinal row of short setae on lateral face. Ischium with 1 to 3 small spines on ventral margin (first leg), or unarmed (second leg). Coxae of ambulatory legs unarmed or with 1-3 small spines ventromesially. Anterior lobe of sternite of second ambulatory legs subsemicircular, setose, armed with simple subterminal spine.

 

Fourth pereopod semichelate. Dactyl subtriangular; shorter than length of propodal rasp, terminating in corneous claw; with ventrolateral row of small, closely-set, corneous spines. Propodal rasp with 1 row of ovate scales at least distally in small to medium size specimens (SL < 9.0 mm), or with 2 or 3 rows of ovate scales in large specimens (SL > 10.0 mm). Carpus with row of long setae on dorsal margin. Merus with setae on dorsal and ventral margins.

 

Fifth pereopod chelate; propodal rasp forming subtriangular area less than half length of propodus.

 

Telson and uropods asymmetrical. Left exopod about 2.4 as long as broad; rasp moderately broad. Telson without lateral indentation, and scattered setae dorsally; terminal margin divided into 2 rounded projections by shallow, often broad, rounded (U-shaped) cleft; margins of rounded projections each armed with 6 to 15 short to moderately long corneous spines, each margin occasionally with additional 7 or 8 much shorter subdistal spines dorsally.

 

 

AFFINITIES. — This species is similar to P. saintlaurentae sp. nov.; however, the two differ in several characters. The scales of the propodal rasp of the fourth pereopod are ovate in P. hothuisi, whereas the scales are lanceolate or conical in P. saintlaurentae sp. nov. The terminal margin of the telson is divided into two rounded projections by a shallow cleft in P. holthuisi; the telson is divided by a deep cleft in P. saintlaurentae sp. nov. The antennal scales are usually armed with four or more strong spines, and exceed the distal margin of the cornea by half or less than half the length of the acicles in P. holthuisi; the acicles are usually unarmed or with one or two weak spines, and exceed the distal margin of the corneae by more than half the length of the acicles in P. saintlaurentae sp. nov.

 

REMARKS. — As previously mentioned, Parapagurus holthuisi Lemaitre, 1989, is a replacement name proposed by LEMAITRE (1989) for P. abyssorum Henderson, 1888, a junior homonym of P. abyssorum (Filhol, 1885a). The "Challenger" material used by HENDERSON (1888) to describe his P. abyssorum included specimens from the Atlantic (Bermuda; Sierra Leone; Tristan da Cunha), western Pacific (Banda, Indonesia; Philippines; north of Papua New Guinea; Yokohama, Japan), and eastern Pacific (west of Valparaiso, and Port Otway, Chile). HENDERSON indicated that his description was based on a male specimen from west of Valparaiso (stn 300); thus, that male must be considered the holotype of his taxon and therefore of P. holthuisi. Examination of HENDERSON's single specimen obtained from Port Otway (stn 304) and deposited in the Australian Museum, Sydney (AM G.1653), has revealed that it actually represents the new species P. janetae, described herein. It has not been possible to examine HENDERSON's material from the western Pacific, and it could represent one or more of the species of Parapagurus that occur in that region.

 

DE SAINT LAURENT (1972, pl. 1, fig. 7) included a photograph of a right cheliped of a specimen of Parapagurus pilosimanus abyssorum. She did not, however, provide locality information for the specimen, and from the appendage alone it is not possible to determine whether it actually is of P. holthuisi.

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Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© National Museum of Natural History, Smithsonian Institution

Source: Antarctic Invertebrates Website (NMNH)

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