Pagurus albus ( Benedict, 1892 )

Ayón-Parente, Manuel & Wehrtmann, Ingo S., 2019, Description of a new species of Pagurus Fabricius, 1775 (Crustacea: Paguroidea: Paguridae) from the Pacific coast of Costa Rica, Central America, with notes on Pagurus albus (Benedict, 1892), Zootaxa 4712 (1), pp. 101-113 : 102-105

Pagurus albus ( Benedict, 1892)

( Figs. 1–3 )

Eupagurus albus Benedict 1892: 6 .— Alcock, 1905: 179.

Pagurus albus Glassell, 1937: 256 , 258.— Steinbeck & Ricketts, 1941: 454.— Gordan, 1956: 325.— Westervelt, 1967: 49, fig. 18.— Snyder-Conn, 1980: 282.— Hendrickx & Harvey, 1999: 371.— Boschi, 2000: 104.— Lemaitre & Cruz-Castaño, 2004.— McLaughlin et al. 2010: 32.

Material examined. 3 males (SL 5.1–5.8 mm), off Rocas Consag, Gulf of California, 31°18’12’’N, 114°25’W, 04 August 1985, trawl, 29 m, ICML-EMU-3703 ; 1 female (SL 1.9 mm), off Rocas Consag, Gulf of California, 31°20’36’’N, 114°23’30’’W, 04 August 1985, Van Veen dredge, 25 m, ICML-EMU-6987 ; 2 males (SL 1.2–2.5 mm), off Punta Arboleda, Gulf of California, 26°55’36’’N, 110°05’W, 05 May 1982, trawl, 23 m, ICML-EMU- 6988 ; 2 females (SL 4.6–5.4 mm), Bahía Kino, Sonora, Gulf of California, 25°45’44’’N, 111°56’30’’W, 09 March 2007, oyster dredge, 1 m, ICML-EMU-8255 ; 1 male (SL 3.5 mm), Estero de la Cruz, Bahía Kino , Sonora, 12 July 2009, collected by hand, ICML-EMU-10163 ; 4 females (SL 2.9–4.1 mm), 3 NS (NM), Topolobampo, Sinaloa, Gulf of California, 25°33’05’’N, 109°05’02’’W, 26 November 2004, collected by hand, ICML-EMU-10164 ; 1 male (SL 2.4 mm) and 4 females (SL 2.1–2.6 mm), Punta Prieta, Topolobampo, Sinaloa, Gulf of California, 25°32’05’’N, 109°05’01’’W, 25 November 2004, collected by hand, ICML-EMU-10165 ; 1 ovigerous female (SL 5.0 mm), 24°35’20’’N, 107°49’58’’W, Bahía Altata , Sinaloa, 22 March 1991, oyster dredge, 4 m, ICML-EMU-10242 ; 1 male (SL 2.6 mm) 2 females (SL 2.2–2.5 mm), 3 NS (NM), and 1 ovigerous female (SL 3.8 mm), Punta Prieta, Topolobampo, Sinaloa, Gulf of California, 25°32’5’’N, 109°05’01’’W, 29 November 2004, collected by hand, 1 m, ICML-EMU-10829 ; 3 females (SL 4.3–5.2 mm), Ensenada del Pabellón , Sinaloa, 24°26’02’’N, 107°39’06’’W, 12 December 1990, collected by hand, ICML-EMU-10843A ; 1 male (SL 2.6 mm), Ensenada del Pabellón, Sinaloa, 24°30’15’’N, 107°41’58’’W, 13 December 1990, oyster dredge, 2 m, ICML-EMU-10843B ; 1 NS (NM), Bahía Altata , Sinaloa, 24°35’20’’N, 107°49’58’’W, 22 March 1991, oyster dredge, 4 m, ICML-EMU-12418 ; 3 males (NM), Ensenada del Pabellón , Sinaloa, 24°29’56’’N, 107°41’19’’W, 02 May 1990, collected by hand, ICML-EMU- 12430 .

Description. Eleven pairs of biserial gills weakly divided distally ( Fig. 1A ). Shield ( Fig. 1B ) about 1.1 times as broad as long; anterolateral margins sloping; anterior margin between rostrum and lateral projections concave; anterolateral angle with slit; posterior margin roundly truncate; dorsal surface flattened, with numerous tufts of short setae. Rostrum obtusely triangular, length equal to or slightly exceeding lateral projections; lateral projections obtusely triangular, armed with small spine.

Ocular peduncles ( Fig. 1B ) stout, short, approximately 0.7 length of shield; slightly constricted medially, dorsal surface with few tufts of short setae. Cornea dilated, width about 0.6 length of ocular peduncle. Ocular acicles bluntly subtriangular, weakly concave dorsally, tip rounded, with small, submarginal spine, usually not visible, with moderately long setae; acicles separated basally by about 0.5 basal width of 1 acicle.

Antennular peduncle ( Fig. 1B ), when totally extended, exceeding ocular peduncle by 0.5–0.8 length of ultimate segment; ultimate and penultimate segment both with few short setae on dorsal surface; basal segment with moderately strong spines on latero-subdistal margin.

Antennal peduncle ( Fig. 1B, C ) moderately long, exceeding ocular peduncle by 0.7 length of ultimate segment. Fifth segment unarmed, with scattered setae on dorsal and ventral margins. Fourth segment unarmed, with scattered setae. Third segment with small spine on ventrodistal margin, partially obscured by tufts of setae. Second segment with dorsolateral distal angle produced (reaching about 0.3 of antennal acicle), terminating in strong spine, lateral margin unarmed; dorsomesial distal angle with strong spine, mesial margin with short setae. First segment with one small ventral laterodistal spine. Antennal acicles moderately long, about as long as ocular peduncles, exceeding distal margin of fourth antennal peduncle segment, terminating in tipped spine; dorsal surface and mesial margin with tufts of short setae. Antennal flagella long, exceeding tip of right cheliped; each article with a few short bristles (shorter than 1 article length).

Mandible ( Fig. 2A ) with upper and lower incisor edges calcareous; palp 3-segmented, ultimate segment setose, nearly as long as combined length of penultimate and basal segments. Maxillule ( Fig. 2B ) with proximal endite subquadrate, distal endite subrectangular, enlarged distally; endopod with external lobe moderately developed (subtriangular), not recurved; internal lobe with long terminal bristle and usually one seta. Maxilla ( Fig. 2C ) with endopodite inflated basally, exceeding scaphognathite by 0.3 in distal extension. First maxilliped ( Fig. 2D ) with endopodite approximately 0.5 length of exopodite; basal segment of exopodite inflated. Second maxilliped ( Fig. 2E ) without distinguishing characters. Basis of third maxilliped ( Fig. 2F ) with 1 spine; ischium with well-developed crista dentata, consisting of 9 corneous-tipped teeth and one accessory tooth; merus with small spine at dorsodistal margin.

Chelipeds unequal ( Fig. 3A, B ), right longer than left. Right cheliped long and stout. Dactyl moderately long, about 0.8 length of propodus; dorsal surface with row of conical spines decreasing in size distally and some small granules or tubercles proximally; mesial margin with row of small conical spines decreasing in size distally; cutting edge with row of calcareous teeth, ending in calcareous claw. Palm as long as broad, very slightly bent upward; dorsal, mesial, lateral, and ventral surfaces thickly set with rough, flattened granules, those on middle surface larger than others; dorsomesial margin conspicuously marked by raised ridge; dorsolateral margin with conical calcareous teeth, decreasing in size proximally and distally. Fixed finger with cutting edge bearing few calcareous teeth, ending in small claw. Carpus slightly longer than palm; mesial surface flattened, upper and outer faces rounded; ventral surface inflated or convex; upper surface longitudinally divided into two parts by median line of small spiny granules increasing in size distally; surface of inner division concave, outer one convex. Merus armed with 6 or 7 stout conical spines on distal margin, and numerous small conical spines or granules on mesial and lateral margins; dorsal, mesial, outer, and ventral surfaces with flattened granules; tubercles larger on ventrolateral distal margin. Ischium with row of small denticles or spines on ventromesial margin.

Minor cheliped ( Fig. 3C, D ) enlarged, reaching proximal 0.3 of palm of major cheliped, dactyl and fixed finger slightly ventrally curved. Dactyl about 1.5 times length of palm, dorsal surface weakly convex with submedian longitudinal row of small spine-like tubercles; dorsomesial margin not well defined, with row of small spine-like tubercles extending to proximal half; mesial surface with few spine-like tubercles flattened proximally; ventral surface with few tufts of long setae; cutting edge with corneous teeth, ending in large corneous claw. Palm as broad as long, 0.6 times length of carpus, with surface near dorsolateral margin slightly concave, and dorsomesial margin convex; dorsolateral margin with row of spine-like tubercles extending on fixed finger; dorsal surface covered with spine-like tubercles, extending on fixed finger, larger medially; cutting edge of fixed finger with rounded calcareous teeth interspaced with corneous teeth. Carpus as long as merus, subtriangular in dorsal view; middle-dorsal surface and dorsomesial margin with row of spine-like tubercles; all surfaces covered with tubercles; dorsodistal margin with few spine-like tubercles. Merus subtriangular, dorsodistal and subdistal margins with numerous calcareous teeth extending on lateral surfaces; mesial, outer and ventral surfaces with numerous short rows of small calcareous teeth; ventrolateral distal margin with few small calcareous teeth. Ischium with row of small calcareous spines on ventromesial margin. In major and minor chelipeds, all spines or spine-like tubercles fringed with very short setae.

Second and third pereiopods similar ( Fig. 3E, F ), long, reaching half-length of fixed finger of right cheliped; dorsal and ventral surfaces with tufts of moderately long, stiff setae. Dactyl slender, long and slightly curved ventrally, 1.5–1.6 times length of propodus, ending in sharp corneous claw; dorsal margins with row of small calcareous spines on proximal half, decreasing in size distally and accompanied by long stiff setae; mesial faces with longitudinal groove medially, shallower distally and flanked proximally by few small calcareous spines; dorsomesial margin with row of corneous spines; lateral faces with longitudinal groove medially, shallower distally, flanked dorsally by row of small spine-like tubercles on proximal half; ventral margins each with row of very slender spines flanked by long setae. Propodus elongated, 1.3–1.5 length of carpus; dorsal surfaces with short transverse rows of small protuberances, scale-like tubercles fringed distally by short setae; mesial, lateral and ventral faces with numerous flattened protuberances or scale-like tubercles fringed with short setae. Carpus with numerous scale-like tubercles fringed with short setae on dorsal and outer surfaces; those on dorsal surface stronger; outer surface somewhat inflated, with toothed distal margin; mesial and ventral surfaces smooth. Merus 1.3–1.5 times length of carpus, with dorsal surface with a row of small protuberances becoming in scale-like tubercles distally; distal margin fringed with small teeth; mesial surface smooth, ventromesial margin with small, simple or toothed tubercles; outer surface and ventrolateral margin with numerous flatted protuberances or scale-like tubercles. Ischium with row of small spines on ventromesial margin.

Sternite XII (third pereiopods) with subrectangular anterior lobe ( Fig. 1D ), bearing long stiff setae.

Fourth pereiopods ( Fig. 1E ) semichelate. Dactyl without preungual process at base of claw, with ventrolateral row of 15–17 closely set, small, corneous spines. Propodal rasp with 2–3 rows of lanceolate scales.

Fifth pereiopods chelate. Dactyls with three rows of small ovate scales on proximal half and one row on distal half. Propodal rasp with 13–14 rows of lanceolate scales, extending posteriorly to nearly midpoint of segment. Coxae almost symmetrical.

Males and females with paired gonopores and unpaired pleopods 2–5. Males with biramous pleopods 3–5, exopod well developed with endopod reduced or obsolete. Females with pleopods 2–4 biramous, rami moderately developed; pleopod 5 weakly developed, uniramous.

Uropods asymmetrical. Telson ( Fig. 1F ) subrectangular, with posterior lobes asymmetrical, left slightly longer than right, separated by very shallow median cleft; terminal margins almost straight, each with 2 or 3 rows of calcareous spines; marginal spines longer than submarginal ones; anterior lobes unarmed, margins with long setae.

Color in life. General ground color white or tan; eyes black ( Westervelt 1967).

Distribution. Percebu Lagoon, Baja California; Cholla Bay, Sonora, Altata Bay, Sinaloa, Gulf of California, Mexico ( Snyder-Conn 1980; Romero & Carvacho 1987; Hendrickx & Harvey 1999).

Remarks. Hendrickx & Harvey (1999) indicated that Pagurus albus is also present in Costa Rica on the basis of information given by Janet Haig. The examination of the material deposited in the Regional Collection of Marine Invertebrates in Mazatlán and in the Crustacean Collection of the Museo de Zoología revealed, however, that the material from Costa Rica belonged to another species, hence the geographic distribution of P. albus is currently limited to the Gulf of California, Mexico.

Figures

FIGURE 1. Pagurus albus (Benedict, 1892) ICML-EMU-3703. A, gill lamellae; B, shield and cephalic appendages, dorsal view; C, right antennal segments 1–5and antennal acicle, in ventrolateral view; D, sternite XII of third pereiopods; E, dactyl, propodus and carpus of 4th right pereiopod, outer view; F, telson, dorsal view. Scale: A = 1 mm; B = 5 mm; C–F = 2 mm.

FIGURE 2. Pagurus albus (Benedict, 1892) ICML-EMU-3703. A, mandible; B, maxillule; C, scaphognathite; D, 1st maxilliped; E, 2nd maxilliped; F, 3rd maxilliped. Scale: 1 mm.

FIGURE 3. Pagurus albus (Benedict, 1892) ICML-EMU-3703. A, 1st right pereiopod, dorsal view; B, same, mesial view; C, 1st left pereiopod, dorsal view; D, same, mesial view; E, 2nd right pereiopod, mesial view; F, same, outer view. Scale: 5 mm.