Bathytropa rifensis sp. nov.

(Figures 12–14)

Material examined

Holotype: ♂, St. 15, sieved ground near stream, leg. S. Taiti, 27 April 2004 (MZUF 9474). Paratypes: 2 ♂♂, 5 ♀♀, same data as holotype (MZUF 9474).

Description

Maximum length: ♂, 2.8 mm; ♀, 4.0 mm. Colour pale. Body strongly convex with epimera of pereon and pleon enlarged, obliquely directed, clinger type (Schmalfuss 1984). Dorsal surface of cephalon, pereon and pleon with large tubercles and ribs arranged as in Figure 12A. Back covered with triangular scale-setae (Figure 12B); posterior margins of the body segments with rectangular scale-setae (Figure 12C); one line of noduli laterales per side arranged on top of the outmost tubercle of the posterior row of each pereonite. Cephalon (Figure 12D, E) with median lobe raised up, broadly rounded in dorsal view and rectangular in frontal view; quadrangular lateral lobes, obliquely directed and slightly more protruding frontwards than median lobe; no suprantennal line; eye small with five ommatidia. Pereon with quadrangular epimera progressively pointing backwards from first to seventh; posterior margin of the first pereonite slightly sinuous at sides. Pleonites 3–5 with subrectangular epimera continuing the outline of the pereon. Telson slightly wider than long, triangular with straight sides and broadly rounded apex (Figure 12F). Antennule (Figure 12G) with second article much shorter than first and third; third article with an apical tuft of four aesthetascs. Antenna (Figure 12H) with flagellum about as long as fifth article of peduncle; second flagellar article about four times as long as first, bearing a row of four aesthetascs in the middle. Mandibles with molar penicil consisting of four or five hairy setae; left mandible (Figure 13A) with 2 + 1 free penicils; right mandible (Figure 13B) with 1 + 1 free penicils. Maxillule (Figure 13C) outer branch with 4 + 7 (3 cleft) teeth; inner branch with two short stout penicils and a distinct apical point. Maxilla (Figure 13D) distally bilobate with setose apex; inner lobe much wider than outer one. Maxilliped (Figure 13E) endite with three triangular stout teeth on distal margin and no penicil; first article of palp with two setae, the medial one much longer than the outer one. Pleopodal exopods with no respiratory structures as in most species of the genus.

Male: Pereopod 1 (Figure 13F) with no distinct sexual modifications. Pereopod 7 (Figure 14A) ischium enlarged in the distal part, with straight sternal margin. Pleopod 1 (Figure 14B) exopod subtriangular with rounded distal part; endopod with pointed apical part slightly bent outwards. Pleopod 2 (Figure 14C) endopod with apical part flagelliform, slightly longer than exopod. Pleopod 3–5 exopods as in Figure 14D–F.

Etymology

The name refers to Rif where the specimens have been collected.

Remarks

At present the genus Bathytropa includes 10 species distributed in the Mediterranean area (Schmalfuss 2003). According to Vandel (1962), B. meinertii Budde-Lund, 1885 includes two subspecies: B. m. meinertii and B. m. costata Budde-Lund, 1885. The new species is readily distinguishable from B. meinertii costata, B. tuberculata Racovitza, 1908, and B. schembrii Caruso and Lombardo, 1982 in the presence of two paramedian tubercles instead of a single median tubercle on pleonites; from B. granulata Aubert and Dollfus, 1890 and B. graevei (Verhoeff, 1940) in having distinct dorsal ribs and tubercles instead of granulations; from B. wahrmani Strouhal, 1968 in the telson triangular with rounded apex, instead of hour-glass-shaped, and the absence of respiratory structures on the pleopods; from B. meinertii meinertii, B. colasi Vandel, 1954, B. dollfusi Strouhal, 1936, B. patanei Caruso, 1973a and B. ruffoi Caruso, 1973b in the number and disposition of dorsal ornamentation. In northern Africa three species of Bathytropa were previously recorded: B. tuberculata and B. meinertii, with both subspecies B. m. meinertii and B. m. costata, from Algeria, and B. colasi Vandel, 1954 from ‘Berberie’ (Vandel 1955b).