Allotrichotriura, P., 2009

Mendes 1 Eduardo, Luis F., Fox, G. P., Solis, Daniel R. & Bueno, Odair C., 2009, New Nicoletiidae (Zygentoma: Insecta) from Brazil living in fire-ant (Hymenoptera: Insecta) nests, Papéis Avulsos de Zoologia 49 (34), pp. 467-475 : 469-473

Allotrichotriura gen. nov.

Description: Female: Nicoletiidae Subnicoletiinae of small body size (<4 mm), ateluriform (short and stout), lacking pigment and without scales; most of the setae are thin and very short (only a few acute or apically slightly bifurcated macrochaetae exist on the head and tergites). Head exposed, setose. Nota, abdominal tergites and sternites, with setae arranged in several irregular rows. Incisive and molar areas of mandibles well developed. Galea and lacinia equally developed; galea with 1 apical conule only, the prostheca not clearly longer than the apical tooth of lacinia. Maxillary and labial palps typical. Praetarsus simple and complete. All abdominal segments exposed. Stylets on abdominal segments VI-IX (4 pairs), vesicular structures reduced to pseudovesicles VII. Subgenital plate widely elliptical, the ovipositor spindle-shaped, with thin setae only and clearly longer than level of stylets IX. Cerci and paracercum short, lacking spines. Male sex unknown.

Type-species: Allotrichotriura saevissima sp. nov.

Etymology: From the Greek, Allos: other, and from Trichotriura Silvestri, 1918 , a West African genus probably quite close to the new endemic Brazilian genus.

Discussion: The new genus fits within Subnicoletiinae (sensu Mendes, 1994), probably a polyphyletic group as judiciously suggested by Smith (1998), known from the Neotropical, Afrotropical, Oriental and Australian Regions. It includes 11 genera, namely Hematelura Escherich, 1906 , Hemitrinemura Mendes, 1994 , Metrinura Mendes, 1994 , Subnicoletia Silvestri, 1908 , Subtrinemura Smith, 1998 , Trichatelura Silvestri, 1932 , Trichotriura Silvestri, 1918 , Trichotriurella Mendes, 2002 , Trichotriuroides Mendes et al., 1994 , Trinemura Silvestri, 1908 and Trinemurodes Silvestri, 1916 .

Allotrichotriura differs from the “nicoletiidshaped” (long, thin, parallel-sided) genera in its shape and by the smaller subgenital plate as well as the number of abdominal stylets and/or vesicles (stylets VI-IX, vesicles VII only in the new genus). Trinemura s.s. (sensu Mendes, 1994, Smith, 1998) also has vesicular structures only on VII but has stylets on III-IX, Hemitrinemura , Metrinura , Subtrinemura and Trinemurodes have stylets on II ( III-IX) and vesicles on II ( III-VII). Trinemurodes lacks, further, empodial claw. Subnicoletia Silvestri, 1908 similarly presents, more numerous abdominal stylets ( IV-IX) and vesicular structures ( IV-VII).

Like the new genus, Hematelura ( Escherich, 1906 and Wygodzinsky, 1958b) and, mainly, Trichatelura Silvestri, 1932 , Trichotriura Silvestri, 1918 , Trichotriurella Mendes, 2002 and Trichotriuroides Mendes et al., 1994 have, like the new genus, more or less “atelurid-shaped” bodies, round, short and broad, as well as a clear reduction of both, the number of abdominal stylets and vesicular structures; the last aforementioned four genera share with Allotrichotriura the single apical conule in the galea but they have stylets restricted to urosternites VII-IX (3 pairs only) or these structures can be even less numerous (one pair only in Trichotriurella ).

Furthermore, Trichatelura , ecitophilous and Neotropical, with 2 known species from Brazil, has a single row of strong setae along the posterior border of the urotergites, thin and cylindrical labial palp apical article, very different subgenital plate, and a much shorter ovipositor. In the new genus all tergal and sternal setae are similarly developed, thin, short and arranged in several irregular rows, being slightly more dense and more developed on posterolateral areas only, with just a single macrochaeta postero-laterally. Trichotriura , termitophilous from Nigeria, with even smaller specimens, shows, like the preceding genus, different dorsal setation, urotergites provided with just one posterior row of well-developed setae; furthermore, the distal article of labial palp is also almost sub-cylindrical.

Trichotriuroides , monotypical and endemic to the Equatorial Guinean island of Bioko (formerly Macias Nguema, before that Fernando Poo) seems more similar to Allotrichotriura though the comparison remains difficult as the type-series of the new genus includes exclusively females while Trichotriuroides remains known from a single male. Main differences seem to concern the almost completely concealed abdominal tergite I due to the proportional development of the thorax (free in the new genus), the cylindrical labial palp distal article (oval in Allotrichotriura ), the distinct empodium, the density of setae along the body (mainly nota) and the lack of thoracic macrochaetae.

Trichotriurella , from the former Zaire and also monotypical, with mature specimens also smaller than those of the new genus is similarly known from females only; among other dissimilarities, there is different cephalic setation, very distinct mandibles and maxillae, longer antennae and only one pair of abdominal stylets.

Hematelura , from Africa with one only representative (autochthonous?) in Brazil, shows (at least in the Afrotropical species we could study) two well developed conules on the galea. This genus presents some variability in the number of abdominal stylets and vesicles, and the 3 known species that completely lack scales, H. convivens Escherich, 1906 , H. setosa (Silvestri, 1918 sub as Monachtinella ) and H. delamarae Wygodzinsky, 1958 are quite distinct from Allotrichotriura . H. convivens , from Brazil, if congeneric with the remaining species and if correctly characterized, has vesicular structures on the abdominal segments VI-VII in contrast to all the remaining Hematelura and to the condition in Allotrichitriura gen. nov.; furthermore, the ovipositor is much longer than in the new Neotropical genus. H. setosa , known exclusively from type material from Guinea, with 5 pairs of stylets (V-IX), is the only species to present (in males) a conspicuous projection on the antennal pedicellus; as a rule in the known females, the ovipositor is much longer than in the new genus; lastly, H. delamarei , from the Ivory Coast, known only by its 5 mm long male holotype, also with 5 pairs of abdominal stylets, shows a distinct, acicular empodium and peculiar, scattered, delicate, lanceolate setae on the urotergites (nothing similar occurs in the new genus).