Alloschizidium magrinii, Taiti & Argano, 2009

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

Alloschizidium magrinii sp. nov.

( Figs 11–12)

Type material. Holotype ♂: OR, South of Montresta , 40°21’19.8”N – 8°29’24.0”E ( WGS84 ), 480 m, under big stones, 24.IV.2007, leg. R. Argano and S. Taiti ( MZUF 9290 ).

Paratypes: 1 ♂, 2 ♀♀, OR, South of Montresta , 40°21’19.8”N - 8°29’24.0”E ( WGS84 ), 480 m , under big stones, 24.IV.2007, leg. R . Argano and S. Taiti ( MZUF 9290 ) ; 1 ♀, same locality, 5.XII.2005, leg. P. Magrini ( MZUF 9291 ) ; 1 ♂, 7 ♀♀, same locality, 27.IV.2008, leg. R . Argano and S. Taiti ( MZUF 9292 ) .

Diagnosis. A blind, colourless species of Alloschizidium characterized by short triangular dorsal scalesetae, a distinct groove along the frontal margin of the cephalon and along the lateral margin of pereonite 1, schisma of pereonite 1 with inner lobe distinctly shorter than outer one, wider than long trapezoidal telson, uropodal exopod as long as wide, and subquadrangular male pleopod 1 exopod.

Description. Maximum length: ♂, 3.5 mm; ♀, 5.0 mm. Body colourless, strongly convex with vertical epimera, able to roll up into a perfect ball ( Fig. 11A). Back smooth, covered with numerous triangular scalesetae ( Fig. 11B); one line of noduli laterales per side on the pereonites, more or less at the same distance from the lateral margin ( Fig. 11A). Cephalon ( Fig. 11C–D) with triangular scutellum slightly depressed in the middle; a distinct groove is present along the whole anterior margin of vertex; postscutellar line not visible, due to the presence of the cephalic groove; eyes absent. Pereonite 1 ( Fig. 11E) with posterior margin slightly concave; postero-lateral schisma with outer lobe rounded and distinctly protruding backwards compared to inner one; lateral margin deeply grooved along its entire length, continuing the cephalic groove. Pereonite 2 ( Fig. 11F) with a small triangular tooth on ventral side. Telson ( Fig. 11G) trapezoidal, wider than long, with slightly concave sides, wide, slightly convex apex. Antennula ( Fig. 11H) of three articles, second article much shorter than the others; a tuft of about eight aesthetascs and a lobate appendix at the apex. Antenna ( Fig. 11I) with flagellum as long as fifth article of peduncle; second flagellar article more than four times as long as first and bearing two rows of aesthetascs. Buccal pieces and respiratory structures on the pleopods as in A. maymon . Uropod ( Fig. 12A) with exopod flattened, quadrangular, as long as wide; endopod distinctly longer than exopod.

Male: Pereopod 1 ( Fig. 12B) with some strong setae on carpus. Pereopod 7 ( Fig. 12C) with no distinct sexual modifications, ischium with straight sternal margin. Pleopod 1 ( Fig. 12D) exopod subquadrangular; endopod with a triangular apical part equipped with a row of short setae. Pleopod 2 ( Fig. 12E) endopod thickset, distinctly longer than exopod. Pleopod 3-5 exopods as in Fig. 12F–H.

Etymology. The new species is named after our friend Dr. Paolo Magrini, a Florentine entomologist, who first collected this species near Montresta.

Remarks. Alloschizidium magrinii is readily distinguishable from all the other species in the genus by the presence of a groove along the anterior margin of the vertex. For the presence of a groove on the lateral margin of the pereonite 1 it also resembles A. igiliense ( Ferrara & Taiti, 1978) from Giglio Island (Tuscan Archipelago), from which it is distinguished, besides by the above mentioned cephalic groove, also by the narrower uropodal exopods and less developed posterior point of the male pleopod 1 exopod (compare to fig. XXV in Ferrara & Taiti 1978).

As most of the species in Alloschizidium , A. magrinii is an endogean form. It was collected under large stones at the margin of a meadow.