Hydrolutos Issa & Iaffe 1999

Derka, Tomáš & Fedor, Peter, 2010, Hydrolutos breweri sp. n., a new aquatic Lutosini species (Orthoptera: Anostostomatidae) from Churí-tepui (Chimantá Massif, Venezuela), Zootaxa 2653, pp. 51-59 : 53

Genus Hydrolutos Issa & Iaffe 1999

External morphology is highly conserved in this genus, for all species as in the original description of Hydrolutos by Issa and Iaffe (1999). In body length the species range between 54– 38 mm in males and 62– 38 mm in females, that tend to be slightly larger than males.

Apterous, nocturnal, brown-coloured anostostomatids. As aquatic insects, on thorax and abdomen with sternal and pleural area covered by fine microtrichia forming a plastron. Head width usually the same than pronotum width. Fastigium horizontal, slightly flattened, not declinate with a definite median carina. Vertex convex. Maxillary palps well-developed, 5 segmented, S1 and S2 short, S3-S5 longer. S5 terminally pilous and swollen. Eyes weakly elevated, oval and pigmented.

Pronotum slightly elevated over mesonotum, as long as broad, with lateral margins indistinct. Thoracic sterna with 2 spines, on prosternum blunt, on mesosternum and metasternum longer, erected. Front tibiae with tympanal organs present on both sides, dorsally with 1 or 2 spines subapically and 2 apically, ventrally with 2 rows of 5 spines (including the apical ones). Middle tibiae dorsally with a row of 4 spines on internal side and a row of 3 spines on external side, ventrally with 2 rows of 5 spines. Hind tibiae with 2 lateral combs, ventrally with 2 long subterminal and 2 long terminal spines. Front femora without spines, but wrinkled on inner margins. Hind femora laterally compressed and with 2 combs of short spines on inner margins. Abdomen towards S9 uniformly segmented. In males epiproct convex, bilobulate apically, with long cerci. Subgenital plate as long as broad. In females ovipositor medium-sized, curved upwards.

Diagnosis. The main difference is in sternal and pleural area covered by fine microtrichia forming a plastron, generally unique within orthopterans. Pronotum gently projected over mesonotum, as long as broad. In Apotetamenus Brunner von Wattenwyl pronotum caudally projected over mesonotum. Front coxae with a distinct spine, medium coxae with blunt spine and hind coxae without a spine. Subgenital plate carries short styles, but there are longer in Lutosa Walker. The species of Neolutosa Gorochov have a typical structure of male abdominal apex, including complicated processes of paraprocts.