Estenarmadillidium, Cifuentes, 2021

Garcia, Lluc, 2023, A new species of Cristarmadillidium from central Spain with remarks on Estenarmadillidium and Iberiarmadillidium (Isopoda: Oniscidea: Armadillidiidae), Zootaxa 5323 (2), pp. 285-292 : 291-292

The genera Estenarmadillidium and Iberiarmadillidium

Two genera of Armadillidiidae with an Eluma - type cephalon, morphologically close to Cristarmadillidium , have been described in the central region of Spain: Estenarmadillidium and Iberiarmadillidium , also very similar between them. Estenarmadillidium was defined solely by its morphological characteristics, while Iberiarmadillidium was erected by morphological examination (including SEM) and multilocus phylogenetic analyses.

Both genera present a small schisma on the first pereon-tergite, a markedly convex body with the tergites few extended towards the sides, allowing an eusphaeric conglobation, dorsal surface with obsolete or hypertrophic granulations, and integument covered with small convex papillae, among other characteristics. This last feature is also present in C. cabanillasi sp. nov. and, at least, in one undescribed species from Andalusia, previously identified as C. breuili (see Garcia 2020).

However, according to the descriptions of the species included in Estenarmadillidium and Iberiarmadillidium , the exopodites of the first male pleopods appear to have a different structure. In the case of E. granulatum , the exopod of the first pleopod has an indented tracheal field, similar to that of all known species of Cristarmadillidium , including C. myrmecophylum , which also has a schisma on the first pereonite. In contrast, in the species of Iberiarmadillidium , the respiratory field of the first male pleopod lacks a notch. The same differences are seen in the exopod of the second male pleopod.

The great external similarities between Estenarmarmadillidium and Iberiarmadillidium , among themselves and also with Cristarmadillidium , could be due to homoplasy, as has already been shown to occur in the case of C. myrmecophilum with Iberiarmadillidium spp.

Cristarmadillidium cabanillasi sp. nov. presents intermediate morphological characteristics between Cristarmadillidium , Iberiarmadillidium and Estenarmadillidium , so in the future the boundaries between these genera should be redefined with the support of molecular data and SEM analysis that, if possible, include all the species known until now.