Michelopagurus atlanticus ( Bouvier, 1922 )

Lemaitre, Rafael & Tavares, Marcos, 2015, New taxonomic and distributional information on hermit crabs (Crustacea: Anomura: Paguroidea) from the Gulf of Mexico, Caribbean Sea, and Atlantic coast of South America, Zootaxa 3994 (4), pp. 451-506 : 486-489

Michelopagurus atlanticus ( Bouvier, 1922)

( Figs. 16–18 )

Pagurodes atlanticus Bouvier, 1922: 24 , pl. 3, fig. 5, pl. 4, fig. 4 (type locality: Azores, between Pico and S. Jorge, Campagnes de S.A.S. le Prince de Monaco of 1902, sta 1349).— Ingle, 1993: 102, figs 69–72.—McLaughlin, 1997: 482. Michelopagurus atlanticus .— McLaughlin, 1997: 482 (by implication).—Udekem d’Acoz, 1999: 179.— McLaughlin et al., 2010: 30.

New material. Brazil. Espírito Santo, TAAF MD55, sta 45 CB 79, 19°01’S, 37°47’W, 1500–1575 m, 28 May 1987: 1 male 2.9 mm (missing right cheliped) ( MZUSP 16813); TAAF MD55, sta 43 CB 77, 19°05’S, 37°47’W, 900– 790 m, 27 May 1987: 1 female 2.1 mm ( MZUSP 16834).

Diagnosis. Shield ( Fig. 16 A) slightly longer than broad, naked or at most with scattered short setae. Rostrum broadly triangular, rounded. Ocular peduncles stout, short, less than half length of shield, with longitudinal row of 3 tufts of short setae on dorsal surface; acicles terminating in simple spine. Antennular peduncles long, exceeding distal margin of cornea by about half of penultimate segment. Antennal peduncle exceeding distal margin of cornea by full length of fifth segment; second segment with distolateral angle produced and terminating in bifid spine; antennal acicle long, exceeding cornea by half length of acicle, terminating in sharp spine, otherwise unarmed except for setae on mesial margin and distally. Chelipeds ( Fig. 16 B–D) elongate, right stouter, exceeding left by about half length of fingers. Right cheliped with scattered setae; chela nearly smooth on all surfaces; carpus with dorsomesial and dorsolateral row of small spines or tubercles. Left cheliped with numerous short, transverse rows of setae dorsally on merus and carpus, and dorsomesial and dorsolateral rows of small spines on carpus. Ambulatory legs ( Fig. 17 A–D) each with dactyls about 1.5 times as long as propodus, with ventromesial row of 10–14 slender spinules; segments unarmed except for scattered short setae on dorsal and ventral margins, and small dorsodistal spine on carpi. Fourth pereopod ( Fig. 17 E) semichelate, propodal rasp consisting of single row of spatulate or lanceolate scales. Anterior lobe of sternite XII ( Fig. 18 C) subdivided into 2 setose lobes. Uropods markedly asymmetrical. Telson ( Fig. 18 A, B) with prominent median cleft separating slightly asymmetrical posterior lobes; rounded terminal margins of posterior lobes each with row of prominent spines, 2 of which are larger on one or both lobes, and spines more numerous and slender in female. Coxae of fifth pereopods of male ( Fig. 18 C, D) symmetrical, each with similar short sexual tube protruding from gonopore. Female with paired, 1- segmented first gonopods ( Fig 18 E) modified as gonopods.

Distribution. Amphi-Atlantic: eastern Atlantic, from the Azores; western Atlantic, off northern coast of Espírito Santo, Brazil. Depth: 790 to 1575 m.

Remarks. This species, originally described in Pagurodes Henderson, 1888 , was assigned by McLaughlin (1997) to her new genus Michelopagurus McLaughlin, 1997 . Michelopagurus atlanticus was previously known only from the female holotype collected in the Azores, eastern Atlantic. Given its depth range from the lower slope to the continental rise, it is not surprising to find M. atlanticus also in the western Atlantic as similar amphi- Atlantic distribution is also known for other deep-water paguroids such as species of the parapagurid genera Parapagurus , Sympagurus , and Oncopagurus (see Lemaitre 1999, 2004, 2014). Bouvier’s (1922) original description of M. atlanticus included only a few, insufficient illustrations, whereas Ingle (1993) included detailed illustrations of the holotype. The discovery of a male and an additional female specimen of this species in the Brazilian collections reported herein, provide the opportunity to present a more complete diagnosis of this species.

Figures

FIGURE 16. Michelopagurus atlanticus (Bouvier, 1922), Brazil. A, D: male 2.9 mm, TAAF MD 55, sta 45 CB 79 (MZUSP 16813); B, C: female 2.1 mm, TAAF MD 55, sta 43 CB 77 (MZUSP 16834). A, shield and cephalic appendages, dorsal; B, right cheliped, dorsal; C, D, left cheliped, dorsal. Scales: 1 mm.

FIGURE 17. Michelopagurus atlanticus (Bouvier, 1922): male 2.9 mm, Brazil, TAAF MD 55, sta 45 CB 79 (MZUSP 16813). A, left second pereopod, lateral; B, dactyl of same, mesial; C, left third pereopod, lateral; D, dactyl of same, mesial; E, propodus and dactyl of left fourth pereopod, lateral. Scales: 1 mm (A – D), 0.25 mm (E).

FIGURE 18. Michelopagurus atlanticus (Bouvier, 1922): A, female 2.1 mm, TAAF MD 55, sta 43 CB 77 (MZUSP 16834); B, C, D, male 2.9 mm Brazil, TAAF MD 55, sta 45 CB 79 (MZUSP 16813). A, B, telson, dorsal; C, sternum, coxae of pereopods, and sexual tubes, ventral; D, sternite XIV, coxae of fifth pereopods, and male sexual tubes, ventral; E, sternite XIV, coxae of fifth pereopods, and first gonopods of female, ventral. Scale: 0.25 mm (A, B, D, E), 0.5 mm (C).