Solitariopagurus cauticolus, Türkay, Michael, 2015

Türkay, Michael, 2015, A new species of Solitariopagurus from the Red Sea with notes on S. profundus (Crustacea: Decapoda: Paguridae), Zootaxa 3920 (4), pp. 579-585 : 580-582

Solitariopagurus cauticolus sp. nov.

(Figs. 1–2)

Holotype. Ovig. ♀, 3.2 × 3.7 mm, SMF 47040, Sudan, Sanganeb Reef, station, off south jetty, outer reef slope, 19°43.18'N, 37°26.5'E, 20 m depth, SCUBA diving, from stones, 29.III.1991, leg. V. Neumann.

Diagnosis. Rostrum rounded, with dorsomedian longitudinal keel. Dorsal surface of carapace with 4 protuberances behind anterior margin, median ones bifid, lateral ones broadly rounded. Ocular peduncles tuberculate anteriorly. Antennular peduncles only slightly overreaching ocular peduncles. Carpus of right cheliped tuberculate in upper half of external face.

Description. Shield (Fig. 1B) much broader than long, dorsal surface with 4 lobes behind anterior margin, median ones bifid at tip, lateral ones more than 2 times as broad as long. Exorbital spine slender, well curved, acute at tip; first anterolateral tooth behind it much shorter, but also spiniform; following (second) tooth triangular, its tip subacute; last (third) tooth at much greater distance than former two, bluntly hook shaped. Rostrum broadly triangular, rounded at tip, with subconvex lateral borders and longitudinal keel in midline. Linea transversalis forming a broad and regular curve towards posterior side of shield, posteromedian plate narrowest at midline, posterior carapace lateral lobes trapezoid, narrower distally than proximally. Remaining posterior parts of carapace membraneous.

Ocular peduncles (Fig. 1C) of nearly half length of shield including rostrum, slightly constricted behind cornea, anterior face proximally with prominent triangular protrusion, dorso-frontal face with irregular row of 4 tubercles.

Sternum (Fig. 1D) with sternite of third maxilliped produced in two spines anteriorly at either side of midline and tubercle about halfway between terminal spine and lateral corner; sternite of chelipeds clearly broader than long, with deep concave indentation in midline and acute teeth on either sides of it, lateral borders slightly curved; sternite of second pereopods broader than long, with V-shaped indentation on lateral borders, posterolateral borders rounded, plate with deep longitudinal furrow in midline; sternite of third pereopods with well separated crescentshaped anterior lobe, posterior lobe with median indentation.

Third maxilliped endopodite pediform, all articles smooth, without any spines. Basis-ischium as long as merus. carpus shorter than merus, enlarged towards its distal end, forming a terminal bulge. Propodus as long as merus, with a group of long setae close to its anteroventral corner. Dactyl shorter than propodus, slightly tapering towards rounded tip, with short setae along its ventral margin, and a tuft of long ones at the distal end.

Right cheliped merus ( Fig. 2 A) triangular in cross section, all three margins with row of small spines, the most proximal one of upper margin much longer than the others, lower margin with spines of alternating sizes, upper and lower faces granulate, granules getting larger towards midline. Carpus ( Fig. 2 C) about of same length as merus, its anterior face with irregularly arranged pointed tubercles, upper and lower margins slightly elevated. Palm ( Fig. 2 B) broadly ovoid, about as long as carpus, slightly longer than fingers; external surface smooth and shining, upper and lower margins elevated and finely granular; dactyl with larger molar shaped tooth at proximal fourth, otherwise dentition of fingers low and irregular.

Left cheliped missing.

Pereopods 2–3 (P2–3) ( Fig. 2 D) long and slender, pereopod 3 slightly longer than the preceding one. Meri broader at base than at distal end, dorsal and ventral borders with very low serrations, otherwise smooth, without obvious granulation, movable spiniform bristle at distal end of posterior border adjacent to articulation with propodus. Carpi clearly less than half length of meri, without obvious granulation. Propodi smooth on both faces, posterior margin of both with two movable spiniform bristles at 1/3 and 2/3 distance from articulation with carpus and similar double bristle at articulation with dactyl, anterior border with one such bristle at proximal 1/4. Dactyls very slightly shorter than propodi, lower margins with 10 (P2) and 11 (P3) movable spiniform bristles. Pereopod 4 ( Fig. 2 F) strongly subchelate, rasp with few spines. Pereopod 5 subchelate, fingers similarly long.

Female genital opening on posterior face of left coxa only.

Abdominal somites membraneous, hardly discernible; somites IV and V of a broadly rounded shape; somite VI subquadrangular, with well discernible transverse suture at anterior fourth. Three unpaired uniramous pleopods.

Telson twice as long as broad, rounded terminally, with strong suture at posterior third. Uropod ( Fig. 2 E) protopodite with posteriorly directed spine, endopod elongate and rounded at tip, exopod broadly rounded, both with well developed rasps.

Males unknown

Remarks. This species is easily distinguished from all others of the genus through the bifid mesial lobes behind the anterior carapace margin (in all other species this lobe is entire or missing as in S. profundus ); the strongly tuberculate anterior face of the ocular peduncles reaching along the whole stretch between the cornea and the proximal end, while in the only other species with ocular tubercles, S. trullirostris , the tubercles are grouped in the centre of the peduncle; the strongly tuberculate external face of the cheliped carpus where the tubercles are not confined to the midline and spread over most of the surface.

FIGURE 1. Solitariopagurus cauticolus , holotype, ovig. ♀, 3.2 × 3.7 mm, SMF 47040. A, dorsal habitus; B, carapace and cephalic appendages, dorsal aspect; C, right eye; D, sternum (sternites of 3rd maxilliped to 3rd pereopod); Scales: A–B = 1 mm; D–E = 0.5 mm.

This species is apparently reef associated, the only other one taken at a similar habitat, but also considerably deeper is S. trullirostris .

Etymology. The species name is a combination of “cautis” meaning reef in Latin and the suffix –colus signifying “dweller”. This refers to the species being a reef inhabitant.

Figures

FIGURE 2. Solitariopagurus cauticolus, holotype, ovig. ♀, 3.2 × 3.7 mm, SMF 47040. A, right cheliped, upper aspect; B, right chela, external aspect; C, carpus of right cheliped, external aspect; D, pereopods 2 – 4, dorsal aspect; E, uropods and telson, dorsal aspect; F, pereopod 4, dorsal aspect – Scales: A, D – F: 1 mm; B – C = 0.5 mm; E, 0.25 mm.