Baeticoniscus Garcia, 2020

Garcia, Lluc, Miralles-Núñez, Adrià & Pérez-Fernández, Toni, 2020, A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain, Zootaxa 4822 (2), pp. 257-268 : 258-260

Baeticoniscus Garcia , n. gen.

urn:lsid:zoobank.org:act:9AE11B33-FA0D-4BCD-9061-BB3EB2CD9205

Diagnosis. Trichoniscidae (Haplophthalminae) with strong tubercles in the cephalon and pereonites, and smooth third pleonite. Head (cephalothorax) with two small ribs on the front; vertex raised, with a prominent tubercle divided at the apex and two blunt protuberances on the sides; central part of the cephalon with a smaller bilobed tubercle; lateral parts of the cephalon with two tubercles on each side. Pereonites 1–6 with four raised tubercles (2 + 2), the central ones bigger than the external ones, and accessory rugosities on each side; pereonite 7 with two central large and closely tubercles, separated at the base, and two accessory rugosities on the sides. First male pleopod with thick endopod, with striated subconical tip.

Type species. Baeticoniscus bullonorum Garcia , n. sp. (by monotypy)

Etymology. From Baetica, Roman province of Hispania, in the south of the Iberian Peninsula, and oνίσκος (onískos), woodlouse.

Remarks. Within the Haplophthalminae , only three known genera – Acteoniscus Vandel, 1955 , Paracyphoniscus Brian, 1958 and Strouhaloniscellus Tabacaru, 1993 – have the third pleonite completely smooth, which differentiates them from the rest of the genera of this subfamily ( Vandel 1955, 1960; Brian 1958; Tabacaru, 1993). Baeticoniscus is morphologically very close to Acteoniscus Vandel, 1955 and to Paracyphoniscus Brian 1958 , both monotypic and only known from Greece and northeast Italy respectively ( Schmalfuss 2003). Acteoniscus petrochilosi Vandel, 1955 is only known from the Keratea cave, in Attiki ( Alexiou & Sfenthourakis, 2013), and Paracyphoniscus meggiolaroi Brian, 1958 has been collected only from a few caves in the Eastern Alps ( Paoletti 1982; Ruffo & Stoch 2005).

However, the first pleopods of the males of their respective type species are very different. Baeticoniscus can be distinguished morphologically from both genera by the cephalic structure and the shape and arrangement of the tubercles of the pereon, and resembles them by presenting the third pleonite completely smooth, a rare morphological feature in the Haplophthalminae subfamily since, in all other known genera, there exist ribs or protuberances in this body part ( Vandel 1955, 1960).

The first pleopods of the male of Baeticoniscus are of the same type as those of the major part of Haplophthalmus species (i.e. a thick endopod, with striated subconical, or more or less dilated, tip) and different from those of Acteoniscus and Paracyphoniscus . Acteoniscus has the endopod of the first male pleopod showing a striated distal part, but it is narrow and ends with an acute tip ( Vandel 1955). Paracyphoniscus , according to the illustrations provided by Brian (1958), has the same appendix terminating in a subtriangular extension and an overlapping expansion.

The differences between these genera and Strouhaloniscellus are much more important, especially with regard to the structure of the first male pleopod, the tegumentary structures and the shape of the pereonites, amongst other morphological characters (see Tabacaru 1993; Bedek & Taiti 2009). This genus contains two species: S. anophthalmus ( Strouhal, 1939) and S. biokovoensis ( Bedek & Taiti, 2009) , both from the Balkan region.

On the other hand a comparison with Iberoniscus is necessary, since this genus is also represented in the same area of the Iberian Peninsula and it has been collected in the same locality as Baeticoniscus n. gen. Iberoniscus show the same type of male first pleopod as Baeticoniscus but it has a very large tubercle in the third pleonite.

Therefore, given the complexity of this group and while it is not possible to undertake a complete revision of the subfamily through molecular analysis, it is considered convenient to establish a new genus for these specimens from the south of the Iberian Peninsula, based on their distinctive combination of morphological characters.