Pseudopaguristes marocanus ( A. Milne-Edwards & Bouvier, 1891 ) A. Milne-Edwards & Bouvier, 1891

De Matos-Pita, Susana S. & Ramil, Fran, 2015, Hermit crabs (Decapoda: Crustacea) from deep Mauritanian waters (NW Africa) with the description of a new species, Zootaxa 3926 (2), pp. 151-190 : 170-172

Pseudopaguristes marocanus ( A. Milne-Edwards & Bouvier, 1891) n. comb.

( Fig. 13 )

Paguristes Marocanus A. Milne-Edwards & Bouvier, 1891: 151 .

Paguristes marocanus .— A. Milne-Edwards & Bouvier, 1892: 207; 1900: 167, pl. 23 figs. 1–6.— Forest, 1954a: 175, figs. 14, 29, 42 and 45.

Material examined. MUBV 08, 174– 168 m, (41); MUBV 10, 332– 344 m, (1).

Males: 2.11–4.51 mm, females: 2.25–2.55 mm, ovigerous females: 2.22–3.52 mm

Type material. “ Talisman ”, 13 July 1883, no. 91, 115– 140 m, lat. 21°51'N, long. 19°48'W, north of Banc d’Arguin, Sahara coasts, muddy sand, Milne-Edwards & Bouvier det. [MNHN-IU-2008-14991 (= MNHN- Pg1612)], adult male, sl 2.31 mm, entire but third pereiopod detached, with a shell of the gastropod Turritella wareni Ryall & Vos, 2010 .

Additional material. Côtes du Sahara, 1884, De Cuverville coll. [MNHN-IU-2013-11300 (= MNHN- Pg1614)], adult male, sl 2.25 mm, left second pereiopod and both third pereiopods missing, proximal abdomen translucent.

Description. The females, not previously described, are morphologically similar to the males with no major differences other than those attributed to sex. Females are smaller, with one gonopore on each P3 coxa, paired uniramous first pleopods and the brood pouch represented by dense plumose setae; ovigerous females with few (up to 9) but large (average = 0.79 mm) eggs.

Habitat. Reported from bottoms of sand, shells and corals ( A. Milne-Edwards & Bouvier 1900: 169). The species was reported in a left coiled shell of Fusinus maroccensis (Gmelin, 1791) ( A. Milne-Edwards & Bouvier 1891, 1892, 1900; as Sinistralia Maroceana , Fusus marocanus and Sinistralia Marocana respectively) and in a right coiled ‘turritelle’ shell ( A. Milne-Edwards & Bouvier 1900) here identified as Turritella wareni Ryall & Vos, 2010 . All our specimens were without a shell.

Distribution. Western Sahara ( A. Milne-Edwards & Bouvier 1900; Forest 1954a) and off Mauritania (Cap Blanc) (present work) in depths from 115–140 m ( A. Milne-Edwards & Bouvier 1900: 169) to 332–344 m (present work). This is the first record since the original description and the first record of the species in Mauritanian waters.

Remarks. The original description of Pseudopagurus marocanus n. comb. included only a short diagnosis within the report of the first hermit crab inhabiting a left coiled shell ( Milne-Edwards & Bouvier 1891). The same short description was included in the preliminary report of the hermit crabs collected by the Travailleur and the Talisman ( A. Milne-Edwards & Bouvier 1892) , but a detailed description and some figures of the species, based on five specimens collected by the Talisman in 1883, were not provided until 1900 ( Milne-Edwards & Bouvier 1900). Of these five collected specimens, only two are now deposited in the MNHN and were reviewed for this work: one male from 26°N, 17°08'W (caught off Cap Bojador, at 130 m depth) figured by Milne-Edwards & Bouvier, 1900 (see Forest 1954a), and another male from 21°51'N, 19°48'W (north of Banc d’Arguin, but off W Sahara coasts, at 115–140 m). The location of the other three specimens, one male from 21°51'N, 19°48'W (135–290 m) and another two specimens from 21°51'N, 19°48'W (115–140 m, no sex specified) is unknown. One male collected by Cuverville in the western Sahara was deposited in MNHN, Paris ( Forest 1954a) and was also reviewed here as additional material.

Despite the limited number of specimens mentioned in the literature, this species was very abundant at station MUBV08, where 237 specimens were captured (41 preserved for further study). All these specimens coincide with those described by A. Milne-Edwards & Bouvier (1900) and Forest (1954a) as Paguristes marocanus and we were certain about their identification. However, in all the examined specimens, including the type and additional material from MNHN of Paris, we found only eight pairs of functional gills, no arthrobranchiae on thoracic segment 3 (over maxilliped 3) and very reduced or absent on segment 4 (over chelipeds), and pleurobranchiae absent on thoracic segment 5 (over pereiopod 2).

The genus Pseudopaguristes was erected by McLaughlin (2002) for those species closely related to Paguristes but with eight pairs of functional phyllobranchiae; subsequently, Rahayu (2005) amended the diagnosis and transferred some species previously included in Paguristes to Pseudopaguristes .

In agreement with these authors, and after reviewing the type material, we conclude that Paguristes marocanus should be included in genus Pseudopaguristes , as Pseudopaguristes marocanus n. comb.

Our male specimens agree with the type material checked during this study but we noticed some variation in the eyestalk and cornea related with size. In the small specimens the eyestalk is shorter and stout with a more inflated cornea, whereas in bigger specimens the eyestalk is slender and the cornea is not so dilated. In addition we decribed here the females of this species for the first time.

Our records of Pseudopaguristes marocanus n. comb. off Cape Blanc are the southernmost and deepest ever reported.

Figures

FIGURE 13. Pseudopaguristes marocanus (A. Milne-Edwards & Bouvier, 1891) n. comb. Type, adult male, sl: 2.31 mm [MNHN-IU- 2008 - 14991 (= MNHN-Pg 1612)]: A, shield and cephalic appendages. B, chelipeds, left up, right down. Adult male, sl: 4.51 mm (MUBV 10; UVIGOBA 3 - 12151): C, shield and cephalic appendages. Adult male, sl: 3.34 mm (MUBV 08; UVIGOBA 3 - 11844): D, chelipeds, left up, right down. Scale: A, 0.5 mm; B – D, 1 mm.