Areopaguristes waldoschmitti, Ayón-Parente, Manuel & Hendrickx, Michel E., 2012

Ayón-Parente, Manuel & Hendrickx, Michel E., 2012, Two new species of hermit crabs of the genus Areopaguristes Rahayu & McLaughlin, 2010 (Crustacea: Anomura: Paguroidea: Diogenidae) from the eastern tropical Pacific, Zootaxa 3407, pp. 22-36 : 30-35

Areopaguristes waldoschmitti sp. nov.

( Figs 4–6 )

Paguristes sp.— Schmitt, 1939:9. Haig et al., 1970: 19. — (?) Ramírez-Guillen, 1983: 72, fig. 20. Areopaguristes sp. 2. — Ayón-Parente & Hendrickx, 2010: 4.

Material examined. Holotype: male (SL 1.34 mm), Punta Arboleda (26º55’36”N, 110º05’06”W), Sonora, COR- TES I cruise, St. 16, 0 5 May 1982, 24 m, trawl (EMU-9535). Paratypes: 1 male (SL 1.10 mm), Punta Arboleda (26º56’36”N, 110º05’06”W), CORTES I cruise, St. 16, 0 5 May 1982, 24 m, trawl (EMU-9536); 1 male (SL 1.30 mm) and 1 ovig. female (SL 1.02 mm), Punta Arboleda (26º56’36”N, 110º05’06”W), CORTES I cruise, St. 16, 0 5 May 1982, 24 m, trawl (EMU-9537); 1 male (SL 1.30 mm), Punta Arboleda (26º56’36”N, 110º05’06”W), COR- TES I cruise, St. 16, 0 5 May 1982, 24 m, trawl (LACM- 1982-2180); 1 male (SL 2.10 mm), off Las Cabras (22º43’8”N, 106º10’43”W), Sinaloa, CEEMEX-C1 cruise, 21 Jun 1990, 30m, trawl (CNCR-26660).

Additional material. 3 males (SL 2.45–3.35 mm) and 2 ovig. females (SL 2.25 mm), Boca de López Mateos, Baja California Sur, 23 May 2008 (CICIMAR-2200); 1 male (SL 2.66 mm), Los Praditos, Estero Santo Domingo, Baja California Sur, 3 Apr 2006, 1 m (CICIMAR-2201).

Description. Shield ( Fig. 4 A) 1.00–1.10 times as long as broad; dorsal surface with a few spines or spinules and tufts of long setae anteriorly, particularly laterally; a well marked, anterior median concavity. Rostral tooth broadly obtuse or obsolete, shorter than lateral pojections; lateral projections triangular, obtuse with marginal spine. Margin between rostrum and lateral projections slightly concave or straight. Anterolateral angles each armed with strong or moderately strong spine; posterior margin rounded. Branchiostegites with row of strong or moderately strong spines on dorsal margin, partially concealed by tufts of long setae; distal margin with tufts of long setae.

Ocular peduncles ( Fig. 4 A) cylindrical, straight, broadest basally, length about 0.77 length of shield; dorsomesial margin with row of tufts of short setae; cornea small, slightly dilated; corneal diameter 0.28 length of ocular peduncles. Ocular acicles subtriangular, broad basally, mesially contiguous, ending in strong single or bifid spine; lateral margins with 3–5 spines.

Antennular peduncles ( Fig. 4 A) long, when totally extended exceeding in length to ocular peduncles by length of ultimate segment; ultimate and penultimate segments unarmed, with some long setae on dorsal margin; basal segment with a spine at ventromesiodistal and dorsolaterodistal margins.

Antennal peduncles long, equalling in length to ocular peduncles or exceeding these by 0.33 length of ultimate segment. Fifth segment unarmed, with some short setae on dorsal and ventral margins. Fourth segment with small dorsodistal spine. Third segment with prominent ventrodistal spine. Second segment with dorsolateral distal angle produced, usually terminating in bifid spine, lateral margin unarmed; dorsomesial distal angle with small spine, mesial margin with tutfs of short setae. First segment with 1 or 2 small spines at laterodistal angle. Antennal acicle equalling in length to fourth antennal segment, almost straight, mesial margin armed with 3 or 4 spines, terminating in bifid or trifid spine. Antennal flagellum short, about 1.25 times length of shield; ventral margin with double row of very long setae.

Mandible without distinghishing characters. Maxillule ( Fig. 5 A) with proximal endite subcircular, distal endite subrectangular, enlarged distally; endopod with one apical seta on weakly produced internal lobe, external lobe well developed, recurved, about 0.50 length of endopod. Maxilla ( Fig. 5 B) with endopod moderately long, slightly exceeding scaphognathite in distal extensión, somewhat inflated basally. First maxilliped ( Fig.5 C) with endopod elongated, about 0.75 length of basal segment of exopod, strongly twisted; proximal segment of exopod subtriangular, tapering distally; flagellum short, distally laminar, with long plumose marginal setae distally; epipod well developed. Second maxilliped ( Fig. 5 D) with basis-ischium fusion incomplete. Third maxilliped ( Fig. 5 E) with basis-ischium fusion incomplete; basis unarmed; ischium with crista dentata well developed, without accesory tooth; merus with ventral margin unarmed, dorsodistal margin with minute spine; carpus, propodus and dactyl unarmed.

Chelipeds ( Fig. 4 B, C) subequal, left slightly stronger than right; armature similar. Dactyls 1.40–1.50 times length of palms; dorsomesial margin with row of corneous-tipped spines accompanied by tufts of long setae; dorsal surface with longitudinal row of corneous-tipped spines and tufts of setae; mesial surface with irregular transverse rows of single or bifid spine-like tubercles accompanied by tufts of long setae; cutting edge with calcareous teeth interspaced with small corneous spines; large, corneous-tipped claw overlapped by fixed finger. Palms 0.67–0.70 length of carpi; dorsomesial margin with 4 prominent spines accompanied by tufts of long setae, mesial surface with scattered flattened tubercles accompanied by tufts of long setae; dorsal surface flat to slightly convex, with 3 longitudinal rows of corneous-tipped spines, one row extending on entire length of fixed finger; dorsolateral margin with row of corneous-tipped spines increasing in size on fixed finger, lateral surface with longitudinal rows of spine-like tubercles accompanied by tufts of long setae; ventral surface with row of flattened tubercles extending on entire length of fixed finger; cutting edge of fixed finger with calcareous teeth interspaced with small corneous spines; large, corneous-tipped claw. Carpi 0.60 length of meri; dorsomesial margin with 5 (occasionally 6) prominent spines accompanied by tufts of long setae; dorsal surface with some corneous-tipped spines and tufts of long setae; dorsolateral margin with 5 or 6 moderately strong, corneous-tipped spines accompanied by tufts of long setae; mesial and lateral surfaces with scattered flattened tubercles and tufts of long setae. Meri triangular in dorsal view; dorsal margin with flattened tubercles proximally, arranged in short transverse rows of small corneous-tipped spines distally and accompanied by tufts of long plumose setae; subdistal margin with row of spines extending on mesial and lateral surfaces; dorsodistal margin with 4 or 5 moderately strong, corneous-tipped spines and tufts of long setae; mesial surface smooth; lateral surface with numerous small spines or spinules; ventromesial margin with denticles; ventrolateral margin with small corneous-tipped spines. Ischia usually with 1 granule or denticle on ventromesial, margin partially concealed by tufts of long setae.

Second ( Fig. 6 A, B, D) and third ( Fig. 6 C) pereopods slender, long, exceeding chelipeds by length of dactyls, second slightly longer than third and somewhat different in armature; left longer than right. Dactyls 1.40-1.66 length of propodi; dorsal surfaces each with 4 or 5 (second) or 4–6 (third) proximal corneous-tipped spines accompanied by tufts of long setae (small specimens), or row of corneous-tipped spines decreasing in size distally (large specimens); mesial surfaces each with 2 or 3 irregular longitudinal rows of tufts of long setae (juveniles), or tufts of setae acompanied by small corneous spines (large specimens); lateral surfaces each with 2 longitudinal rows of tufts of long setae; ventral margins each with row of 5–9 small or minute corneous spines in distal half, partially concealed by tufts of long setae. Propodi 1.30–1.60 length of carpi; dorsal surfaces each with row of moderately strong, corneous-tipped spines (second), or only with low tubercles accompanied by tufts of long setae (third); lateral surfaces each with 2 longitudinal rows of tufts of long setae; mesial surfaces each with 2 or 3 irregular longitudinal rows of tufts of long setae, frequently associated with protuberances or spinules; ventral margins with tufts of long setae. Carpi moderately long, 0.70 (second) to 0.80–0.90 (third) length of meri; dorsal margins each with row of large, corneous-tipped spines (second) or 1 large dorsodistal spine and row of smaller additional spines (third); lateral surfaces each with weak longitudinal sulcus and 2 or 3 rows of tufts of moderately long setae and 1 or more spines, sometimes with median row of small spines (second); ventral surfaces each with tufts of long or moderately long setae. Meri compressed laterally; dorsal margins each with row of small spines (second) or with only 1 small distal spine (third), and tufts of long setae; lateral surfaces each with low tubercles or spinules and tufts of short setae; ventral margins each with row of small spines and tufts of long setae (second) or with only low protuberances and long setae (third); ventrolateral distal angle with 1 small spine (second) or only tufts of long setae (third). Ischia each with 1 moderately strong dorsodistal spine (second) or unarmed (third); ventromesial margin with row of small spinules (second) or with only tufts of long setae (third).

Sternite of third pereopods ( Fig. 4 D) transversely subrectangular, bilobate, each lobe with tufts of long stiff setae.

Fourth pereopods ( Fig. 4 F, G) weakly semichelate; dactyl short, 0.85 length of propodus, with 2 or 3 strong spines posterior to preungual process; preungual proccess well developed, slender, covered apically with short setae; propodus with propodal rasp consisting of 3 or 4 rows of corneous scales. Carpus and merus unarmed, with tufts of long setae on dorsal margin. Fifth pereopods chelate. Dactyl with 1 or 2 rows of corneous denticles; propodus with rasp well developed.

Male first pleopod ( Fig. 6 E, F) with tuft of setae on mesial margin of basal lobe, upper mesial angle with tuft of setae; internal lobe subcircular, with row of long setae on inner margin; lower lamella with row of long setae on lateral margin, distal margin unarmed; external lobe subtriangular. Second pleopod ( Fig. 4 E) with elongate basal segment, endopod naked or with few setae; appendix masculina with long setae marginally and on inner face. Left pleopods 3–5 with endopod vestigial or rudimentary. Females with paired gonopores; first pleopods absent; pleopods 2–4 with both rami well developed; pleopod 5 as in male. Brood pouch represented by row of long setae posterior to pleopod 4.

Uropods and telson asymmetrical. Telson ( Fig. 4 G) with posterior lobes separated by deep, median cleft; left lobe longer than rigth, subeliptic to subrectangular, with posterior margin armed with 3–6 strong spines, 1–4 near median cleft and 2 stronger corneous-tipped spines towards lateral margin, lateral margin usually with 1 strong spine; rigth lobe subquadrate, distal margin usually armed with 5 corneous-tipped spines, lateral margin unarmed or with 1 small spine. Anterior lobes unarmed, with tufts of long setae on lateral margins and a few setae dorsally.

Color. In life. Carpi of chelipeds red; chelae white with red blotches, which merge to form a transverse band about midway along each finger. Ambulatory legs white; propodus and dactyl each with a proximal and subdistal red ring (adapted of Haig et al. 1970).

In ethanol. Shield with orange spots on cream background; ocular peduncles light pink; cornea honey. Chelipeds stained of orange on white to cream background, dactyl and fixed finger white, with orange band at midlength. Ambulatory legs cream with one subdistal and one proximal orange bands on dactyl, propodus, carpus and merus.

Habitat. Specimens have been collected on sandy substrates, in 1–40 m depth. According to Haig et al. (1970), this species is abundant along the west coast of Baja California. Ovigerous females have been collected in May, June and October ( Haig et al. 1970; Ramírez-Guillén 1983).

Distribution. From Boca de las Animas to Bahía Magdalena, west coast of Baja California Sur, and from Punta Arboleda, Sonora, to Las Cabras, Sinaloa, Mexico, Gulf of California ( Haig et al. 1970; Ramírez-Guillén 1983; this study). The Puerto Peñasco record provided by Ramírez-Guillén (1983) probably corresponds to the material cited by Westervelt (1967; as Paguristes sp.) and, as previously noted (see above), this record belongs to A. lemaitrei sp. nov.

Etymology. The species is named to honor Waldo L. Schmitt in recognition to his great contribution to our knowledge on decapod crustaceans, and who first reported this species of hermit crab. It is treated in the genitive case as a combination of “Waldo” and “Schmitt”.

Remarks. Schmitt (1939) reported on an ovigerous female of Paguristes sp. from Bahía Magdalena, Baja California Sur, Mexico. While referring to material from the same locality, Haig et al. (1970) considered it to be conspecific with Schmitt specimen (identified as Paguristes sp.). Haig et al. (1970) provided a color description which fits the color pattern of A. waldoschmitti sp. nov. In addition to the colour pattern, morphological characters also provided by Haig et al. (1970) convince us that the Bahía Magdalena specimens do, indeed, correspond to A. waldoschmitti sp. nov.

Ramírez-Guillén (1983) collected a series of specimens in Bahía Concepción, on the east coast of the Baja California Peninsula and identified these as Paguristes sp. The color description and morphological features he provided fit well with A. waldoschmitti sp. nov.

Areopaguristes waldoschmitti sp. nov. has major resemblances with A. lemaitrei sp. nov. and A. hummi ( Wass, 1955) , a species from the West Atlantic. All three species are characterized by a broadly round or obtuse rostrum, shorter than the lateral projections; ocular acicles contiguous and multidenticulated, and by stout antennal flagella bearing very long setae ventrally. In A. waldoschmitti sp. nov., the antenular peduncle is proportionally longer and the antennal acicle is shorter than in A. hummi . In A. waldoschmitti sp. nov. the chelipeds are less spiny but the spines are larger compared with A. lemaitrei sp. nov. The distal margin of the inferior lamella of the first male pleopod in A. waldoschmitti sp. nov. is unarmed instead of having the usual row of hook-like spines, a character that separates A. waldoschmtti sp. nov. from all its congeners. In A. waldoschmitti sp. nov., the telson features a deep median cleft on the posterior margin vs a shallow cleft in both A. mclaughlinae and A. lemaitrei sp. nov.

Moran (1984) referred to an undescribed species of Isocheles from El Salvador but did not name it. When comparing the figure of this material with the three species of Areopaguristes now known from the eastern Pacific, it seems likely to belong to the latter genus. Unfortunely we could not review the El Salvador material.

Figures

FIGURE 4. Areopaguristes waldoschmitti sp. nov. Holotype male (SL 1.34 mm). A, shield and cephalic appendages, dorsal view; B, left cheliped, dorsal view; C, left cheliped, mesial view, setae omitted; D, sternite of third pereopods; E, second male pleopod; F, left fourth pereopod, lateral view; G, same, dactyl, enlarged, lateral view, setae omitted; H, telson, dorsal view. Scale bars: A-C 1 mm; D – H 0.5 mm.

FIGURE 5. Areopaguristes waldoschmitti sp. nov. Holotype male (SL 1.34 mm), left mouthparts: A, maxillule, internal view; B, maxilla, internal view; C, first maxilliped, internal view; D, second maxilliped, internal view; E, third maxilliped, internal view. Scale bar: A – E 0.5 mm.

FIGURE 6. Areopaguristes waldoschmitti sp. nov. A-C, E, F, holotype male (SL 1.34 mm); D, male (SL 3.35 mm) (CICI- MAR- 2200). A, second left pereopod, mesial view; B, second left pereopod, lateral view; C, third left pereopod, mesial view; D, dactyl of second left pereopod, mesial view, setae omitted; E, first pleopod, external view; F, first pleopod, internolateral view. Scale bars: A – D 2 mm, E – F 0.5 mm.