Spelaeoniscus coiffaiti Vandel, 1961

Montesanto, Giuseppe, Caruso, Domenico & Lombardo, Bianca Maria, 2011, A new species and new records of terrestrial isopods from Sicily (Isopoda: Oniscidea), Journal of Natural History 45 (31 - 32), pp. 1925-1935 : 1926-1927

Spelaeoniscus coiffaiti Vandel, 1961

( Figures 1–3 )

Material examined

Eight males, 45 females, TP, 1 km from Mazara del Vallo, road to Torretta Granitola, 37 ◦ 37 ′ 37 ′′ N, 12 ◦ 36 ′ 58 ′′ E ( WGS84 ), 2 November 1997, leg. D. Caruso ( CC –DBA) .

Description

This species was first described by Vandel (1961) from specimens from the island of Menorca found from washings of land samples. All collected specimens have a white to pale yellow body; eyes are usually absent, but if present, they exhibit small traces of pigment. Body cylindrical, covered with scales and with dorsal scale-setae. Cephalon with deep antennal furrows one-third the vertex length. Pereonite 1 with an evident posterolateral schisma with inner lobe longer and larger than outer lobe ( Figure 1A ). In this schisma the anterior margin of pereonite epimera 2 fits; pereonite 2 with no interlocking mechanisms. Antennae are short, with first article of flagellum much shorter than second, approximately one-third as long ( Figure 1B ). Telson convex, hemispherical, with a regularly rounded margin. Uropods with trapezoidal endopodites ( Figure 1C ), and also covered with scales.

Male. Pleopods 1 with small egg-shaped exopodite and a long endopodite with a long and twisted tip ( Figure 2A ). Genital papilla bifurcate apically, with internal serrate margins ( Figure 2B ). Pleopod 2 exopodite bigger than pleopod 1 exopodite; a series of small setae appears apically, and a strong seta laterally ( Figure 2C ). The endopodite is thin and elongated, approximately double the length of the exopodite.

Remarks

The genus Spelaeoniscus was instituted by Racovitza (1907) with specimens from an Algerian cave. The author assumed it was a troglobian genus, with the species absolutely absent from the epigean surface. However, 11 species have since been described, with only one from a cave ( Caruso and Lombardo 1977). The genus includes 12 species found in North Africa and in the western Mediterranean area ( Figure 3 ). Five species ( S. debrugei Racovitza, 1907 ; S. sahariensis Paulian de Felice, 1942 ; S. orientalis Vandel, 1959 ; S. kabilycola Vandel, 1948 ; S. hamatus Caruso and Lombardo, 1978 ) are known from Algeria and Morocco. Three species are present in Sicily: S. petraliai Caruso and Lombardo, 1977 , S. ragonesei Caruso and Lombardo, 1977 (the only other cave species; Caruso 1982), and S. coiffaiti Vandel , also present on Menorca and the Iberian peninsula, Spain ( Garcia 2006). Four species are present on four islands around Sicily: S. lagrecai Caruso, 1973 (from Marettimo, Egadi Islands, west of Sicily), S. vandeli Caruso, 1976 (Island of Pantelleria, southwest of Sicily), S. vallettai Caruso, 1976 (Islands of Gozo and Malta, Caruso and Lombardo 1982), S. costai Caruso e Lombardo, 1976 (Island of Ustica, northwest of Sicily).

The genus Spelaeoniscus has a western Mediterranean distribution with strong adaptive radiation; in every small island where the genus is found, only endemic and strongly diversified species were identified. This occurrence is not unusual, because these species are almost exclusively endogean, with very low mobility. However, the presence of the same species in Sicily, Spain and Menorca remains unexplained. Recent colonization may explain this observation for the populations from Spain and Menorca, but it is difficult to make the same statement for the Sicilian population. Sicily seems to have never been connected to the Iberian peninsula.

Figures

Figure 1. Male of Splelaeoniscus coiffaiti Vandel. (A) Epimeron of pereonite 1 in dorsal view; (B) antenna (125 ×); (C) left uropod in ventral view.

Figure 2. Male of Splelaeoniscus coiffaiti Vandel. (A) Pleopod 1; (B) genital papilla; (C) pleopod 2.

Figure 3. Distribution map of Spelaeoniscus species in the western Mediterranean area.