Alloschizidium maymon, Taiti & Argano, 2009

Taiti, Stefano & Argano, Roberto, 2009, New species of terrestrial isopods (Isopoda: Oniscidea) from Sardinia *, Zootaxa 2318, pp. 38-55 : 48-52

Alloschizidium maymon sp. nov.

( Figs 8–10)

Type material. Holotype ♂: CA, Armungia , Baccu Gospuru, Gospuru Cave, 12.XI.2000, leg. C. Onnis and J. De Waele ( MZUF 9289 ).

Paratype: 1 ♀, CA , Armungia , Baccu Gospuru, Gospuru Cave, 12.XI.2000, leg. C. Onnis and J. De Waele ( MZUF 9289 ) .

Diagnosis. A blind, colourless species of Alloschizidium characterized by sparse pointed scale-setae, cephalon with a scutellum clearly separated from the vertex but not protruding above it, schisma of pereonite 1 with inner lobe shorter than outer one, telson trapezoidal with truncate apex, uropodal exopod longer than wide, male pleopod 1 exopod with broadly rounded distal margin.

Description. Length: ♂ and ♀, 6.0 mm. Body colourless, strongly convex with vertical epimera, able to roll up into a perfect ball ( Fig. 8A). Back smooth with sparse pointed scale-setae ( Fig. 8B); one line of noduli laterales per side on the pereonites, more or less at the same distance from the lateral margin ( Fig. 8A). Cephalon ( Fig. 8C–D) with triangular scutellum slightly depressed in the middle and distinctly separated from vertex but not protruding above it; frontal line continuing the scutellar upper margin; postscutellar line semicircular on both sides; antennary lobes quadrangular, obliquely directed frontwards; eyes absent. Pereonite 1 ( Fig. 8E) with posterior margin slightly concave; postero-lateral schisma with outer lobe rounded and distinctly protruding backwards compared to inner one; lateral margin slightly thickened. Pereonite 2 with a small ventral tooth. Telson trapezoidal, almost as long as wide, with slightly concave sides and truncate apex ( Fig. 8F). Antennula ( Fig. 8G) of three articles, second article much shorter than the others; a tuft of about 10 aesthetascs and a lobate appendix at the apex. Antenna ( Fig. 8H) with flagellum as long as fifth article of peduncle; second flagellar article about three times as long as first and bearing four rows of aesthetascs. Mandibles ( Fig. 9A–B) with molar penicil consisting of many setae and 2+2 free penicils on the left and 1+2 on the right mandible. Maxillule ( Fig. 9C) outer branch with 6 (5 cleft)+4 teeth, inner branch with two stout penicils and a small posterior point. Maxilla ( Fig. 9D) with bilobed and setose apex. Maxilliped ( Fig. 9E) endite with two triangular terminal spines, one subterminal strong seta and a triangular spine on medial margin. Pleopods 1 and 2 exopods with monospiracular lungs. Uropod ( Fig. 9F) with exopod flattened, much longer than wide; endopod longer than exopod.

Male: Pereopod 1 ( Fig. 9G) with a row of strong setae on carpus. Pereopod 7 ( Fig. 10A) with no distinct sexual modifications, ischium with straight sternal margin. Pleopod 1 ( Fig. 10B) exopod with a broadly rounded distal margin; endopod with apical part slightly swollen and bearing a row of short setae. Pleopod 2 ( Fig. 10C) exopod with a distal part bent outwards; endopod distinctly longer than exopod. Pleopod 3–5 exopods as in Fig. 10D–F.

Etymology. The new species is named after Maymon, god of the Hades in the Nuragic culture.

Remarks. To date, the genus Alloschizidium includes 10 species distributed in the lands encompassed by the Tyrrhenian Sea ( Taiti & Ferrara 1996; Schmalfuss 2003). In Sardinia two species of Alloschizidium are known: A. sardoum ( Arcangeli, 1933) from some caves near Alghero (SS), and A. cottarellii ( Argano & Pesce, 1974) from Ardara (SS) and southern Corsica. In the shape of the telson and uropods A. maymon resembles A. sardoum (compare description and figs 11–21 in Arcangeli 1933) from which it differs in not having a tomentose appearance, in the cephalic structure with frontal line clearly visible and antennary depression less developed, and male pleopod 1 exopod with rounded instead of acute distal margin. It differs from A. cottarellii (compare with fig. 25 in Taiti & Ferrara 1996) in having the cephalic scutellum distinctly separated from the vertex, and longer telson and uropods. In the cephalic structure the new species resembles A. cavernicolum Taiti & Ferrara, 1995 from a cave in southern Tuscany, but it is readily distinguishable by the shorter dorsal scale-setae, and shorter telson and uropods (see figs 13–14 in Taiti & Ferrara 1995).

Information on the Gospuru Cave, type-locality of A. maymon , can be found in Bartolo and Rattu (1991).