Pagurus forbesii Bell, 1845

Muñoz, J. Enrique García, Cuesta, Jose A. & Raso, J. Enrique García, 2014, Taxonomic study of the Pagurus forbesii " complex " (Crustacea: Decapoda: Paguridae). Description of Pagurus pseudosculptimanus sp. nov. from Alborán Sea (Southern Spain, Western Mediterranean Sea), Zootaxa 3753 (1), pp. 25-46 : 28-35

Pagurus forbesii Bell, 1845

( Figs 2–6 , 13 A)

Pagurus forbesii Bell, 1845: 186 –187, unnumbered figure.— Ingle 1985: 765, figs 2, 8, 18, 46, 57, 63.— Ingle 1993: 133, figs 105–108.

Pagurus forbesi .— Sandberg & McLaughlin 1998: 62, fig. 18.

Eupagurus forbesii .— Henderson 1886: 72.

Pagurus sculptimanus Lucas, 1846: 32 , pl. 3, fig. 6.— Allen 1967: 22, 92 (unnumbered fig.).— Zariquiey Álvarez 1968: 246, figs. 12c, 89c, 90h.

Eupagurus sculptimanus .— Heller 1863.—Milne Edwards & Bouvier 1990: 226.— Selbie 1921: 19, pl. V, figs 4–8.— Nobre 1931: 206, figs 112–113.— Nobre 1936: 129, figs 105, 108.

Material examined. St. Calahonda Malaga, Spain, 36°28.0’N, 04°42.3’W, 25 m: 25-26/11/2004, 8 ♀♀, 9♂♂; 09/ 02/2005, 21 ♀♀, 17♂♂; 18/05/2005, 38 ♀♀, 23♂♂. 2 males MNCN ( CSIC) 20.04/9256 and 20.04/9257, Genbank accession numbers KF962980 -81 / KF962984 -85.

Oran Bay, Algeria: 3 ♂♂, syntypes of Pagurus sculptimanus Lucas 1846 (MNHN-IU-2008-15134 [=MNHN- Pg343], MNHN-IU-2009-3929 [=MNHN-Pg343], MNHN-IU-2009-3930 [=MNHN-Pg343].

Description. Cephalothoracic shield ( Figs. 3 A, 11A). Anteromedial frontal margin not protruding, rounded, with blunt anterolateral processes. Cervical groove deep, distinct. Shield length / eyestalk length = 1.0–1.1.

Eyes. Long eyestalk with cornea slightly expanded; ratio total length / maximum width (cornea) 2.8–3.0; eyes reaching nearly to tip of antennal peduncle and third segment of antennular peduncle. Sub-triangular ocular acicles, with a sub-marginal apical spine.

Antennules ( Fig. 3 B). First segment with outer medial spine. Ratio length / width (in middle) third article = 6.2–6.3. Ratio third /second article length = 2.1. Endopod 8-segmented.

Antenna ( Fig. 3 C). Segment 1 with outer subdistal spine, sometimes as obtuse process or absent; with another ventromesial distal spine. Strong dorsolateral process on second segment of antennal peduncle with 2 teeth on its inner edge, not reaching beyond proximal half of segment 4. Antennal acicle slightly curved, not reaching middle of fifth segment, not reaching base of cornea (less frequently reaching it, but not beyond cornea).

Mouthparts: Mandibles as figured ( Fig. 3 D), palp 3-segmented. Maxillules ( Fig. 3 E) with endopod distally expanded into inner elongated lobe, usually with 2 long, apical setae and with outer distal part expanded as broad, rounded lobe. Maxillae as figured ( Fig. 2 F). Maxilliped 1 ( Fig. 3 G) with exopod peduncle broadened proximally. Maxilliped 2 as figured ( Fig. 3 H). Maxilliped 3 ( Fig 3 I) outer distal margin of carpus and merus without spines; crista dentata (ischium) with 16–18 teeth and 1 accessory tooth; basipod with 2 teeth.

Right cheliped ( Fig. 4 A, 11B–D) much larger than left. In lateral view, upper surface planar, ventral surface convex, forming lid to close opening of gastropod shell. Palm with 3 deep dorsal depressions; largest on outer part, on palm and fixed finger, widest in middle, just opposite base of dactylus. Second depression in proximal part of palm, lying towards inner edge, widest basally. Both separated by blunt, well-marked ridge running from proximal outer part of palm (starting at outer side of strong medial or outer proximal prominence) to basal inner part of fixed finger, following inclined line. Third depression defined by fingers, each with rounded median ridge from which surface slopes rapidly downwards to form marked hollow between fingers. Two strong proximal tuberculatespinous prominences: a more or less medial, sometimes called outer and smaller inner tubercle. Outer margin of hand convex, with row of strong, distinct teeth along length. Inner margin, from base of protopod to base of dactylus, almost straight, dactylus curving towards fixed finger only near tip, with tubercles or teeth well developed. Dorsal surface thickly studded with low rounded flat tubercles. Ventral surface of hand almost smooth, with few tubercles. Fingers end in yellow claws. Carpus presents upper (dorsal) surface granulate-denticulate with 1 or 2 rows of long, strong curved teeth on inner margin. Merus upper surface smooth, ventrally granulate with teeth on distal part more developed in distal outer and inner margins. Ischium with ventral keel with row of 8–14 small teeth and 1 distal-outer-medial small tooth.

Left cheliped ( Figs. 4 B–E, 11D) much smaller than right. Dactylus longer than half propodus length. Fingers end in yellow claws. Base on fixed finger much broader than dactylus at base. Dorsal surface of palm convex transversely in its central part and with outer margin concave, which shows deep rounded depression with outer row of strong teeth oriented upwards. Palmar upper surface with rounded granules more developed in upper central part and mainly on proximal prominence with strong tubercles. Upper surface and outer margin of dactylus practically smooth, with few tubercles. Cutting edge of dactylus furnished with long row of slender transparent spines. Carpus with dorsal, outer row of 5 or 6 long and strong curved teeth, ventral area granulate, sometimes with spines and long setae. Merus with well developed ventral teeth and long setae, 5 or 6 strong teeth on inner margin, with tubercles and smaller teeth on ventral and ventral outer part. Ischium with inner ventral keel with 11–13 small teeth and with 1 or 2 distolateral small teeth.

Pereiopod 2. Left ( Figs. 5 A, B) with ratio of merus/ ischium length 3.3–3.5. Merus with strong ventral teeth, upper face smooth, unarmed. Carpus with 7 or 8 upper teeth (mainly visible from inner view). Propodus with 4–7 small dorsal teeth (seen from inner view), ventrally smooth. Dactylus with articulated spines, but without teeth.

Right second pereiopod ( Fig. 5 C) with ratio of merus/ ischium length 3.5–4.0. Ischium ventral face smooth or with small tubercles, sometimes spinous. Merus with ventral teeth along its length (6 or 7), stronger on anterior margin; upper face smooth, unarmed. Carpus with 8 upper teeth (mainly visible from inner view). Propodus with 8 or 9 strong teeth on dorsal margin. Dactylus with slender articulated spines, but without teeth.

Pereiopod 3. Longer than second pereiopod. Left ( Figs. 5 D, 11E) with ratio merus / ischium length about 1.6. Ischium and merus dorsally and ventrally smooth. Carpus with anterodorsal tooth sometimes following by 3 other smaller (inner view) teeth. Propodus smooth dorsally, with ventral tubercles and teeth (7–11), latter mainly in distal half. Dactylus with ventrally articulated spines and strong teeth extending from distal to proximal part; left third pereiopod dactylus wider than left second pereiopod dactylus.

Right third pereiopod ( Fig. 5 E) with ratio of merus / ischium length 1.6–1.7. Ischium, merus, carpus and propodus dorsally and ventrally smooth. Dactylus with only articulated spines, without teeth (it is different from the left).

Anterior lobe of sternite of third pereiopods ( Fig. 3 J) triangular to subtriangular, setose, with strong acute spines on all margins.

Pereiopod 4 ( Fig 6 A). Dactylus with 14 or 15 ventral spiniform setae, ending in long hyaline claw. Propodus with a denticulate ventral area with row of spiniform setae.

Pereiopod 5 ( Fig. 6 B). Pseudochelate. Dactylus with 20 distal spines on distal margin. Dorsodistal area of propodus with pseudochaetae.

Males pleopods ( Figs. 6 C–F). Males with 4 unpaired pleopods, second to fifth pleopods on left side. Endopods well developed but shorter than half exopod length. Second pleopod smaller than third to fifth pleopods, which are of similar size.

Uropods ( Fig. 6 G). Left about twice size of right and, both, with pseudochaetae on distal part of endopod and exopod.

Telson ( Fig. 3 G). Distinctly bilobed, with median cleft; left lobe slightly larger than right, with 12 and 10 distal subacute processes, largest outermost.

Distribution. Eastern Atlantic: British Isles, Ireland, Norway to Morocco, Madeira (Desertas Island), Canary Islands, possibly Senegal (unconfirmed presence), and the Mediterranean Sea.

Figures

FIGURE 2. Bayesian topology with consistency values of Bayesian reconstruction based on 658 bp of the Cox 1 gene sequences, showing inferred phylogenetic relationships within the European representatives of the genus Pagurus, with represent of the pagurids Calcinus tubularis and Dardanus arrosor as outgroups. Number close to nodes indicates Bayesian posterior probabilities (Pp ≥ 50).

FIGURE 3. Pagurus forbesii. A, cephalothoracic shield and ocular peduncles. B, left antennular peduncle (outer view) and distal part with endopod and exopod. C, antenna, left dorsal view and detail of proximal segments (ventral view). D, left mandible (outer view). E, left maxillule (outer view). F, left maxilla (outer view). G, right first maxilliped (outer view). H, left second maxilliped (inner view). I, left third maxilliped (inner view). J, sternal plate. All scales 1 mm. Setation not shown.

FIGURE 4. Pagurus forbesii. A, right cheliped (outer view) and detail of basal segments. B – E, left cheliped (B general inner view; C, E: details of palm in outer and dorsal views; D, details of ischium and merus). All scales 1 mm. Setation not shown.

FIGURE 5. Pagurus forbesii. A, left second pereiopod (outer view). B, carpus and propodus of left second pereiopod (inner view). C, right second pereiopod (inner view). D, left third pereiopod (outer view) and detail of carpus (inner). E, right third pereiopod (inner view). All scales 1 mm. Setation not shown.

FIGURE 6. Pagurus forbesii. A, left fourth pereiopod and details of propodus and dactylus. B, left fifth pereiopod and detail of dactylus. C – F, second to fifth pleopods. G, uropods and telson (dorsal view). All scales 1 mm. Setation not shown.

FIGURE 13. Junction of both chelipeds to close the mouth of the shell in: A, Pagurus forbesii; B, Pagurus pseudosculptimanus n. sp.; C, Pagurus alcocki (MNHN-IU- 2009.2296).