Cerritulus, Zaldívar-Riverón & Belokobylskij & Braet, 2019

Zaldívar-Riverón, Alejandro, Belokobylskij, Sergey A. & Braet, Yves, 2019, A new aberrant Doryctinae genus (Hymenoptera: Braconidae) from French Guiana, Zootaxa 4604 (2), pp. 381-387 : 382-383

Cerritulus gen. nov.

( Figs 1 A–G)

Type species. Cerritulus forticrura sp. nov.

Diagnosis. Cerritulus gen. nov. can be morphologically distinguished from the remaining described doryctine genera from the American continent by having: 1) tibiae strongly curved on basal quarter, flat and rather wide, 2) femora considerably thick and wide and 3) ovipositor sheaths entirely swollen. This new genus shares most of the above features with the also monotypic, poorly known Oriental genera Ceylonspathius and Termitospathius , though it mainly differs from them by having: 1) all flagellomeres with placoid sensilla (without placoid sensilla in three or four basal flagellomeres in Ceylonspathius and Termitospathius ; Figs 2B , 3C ), 2) fore femora with ventroapical rounded tubercle ( Fig. 1G ) (with a ventroapical pointed tooth in Ceylonspathius and Termitospathius ; Figs 2E , 3F ), 3) crenulate precoxal sulcus present ( Fig. 1D ) (absent in Ceylonspathius and Termitospathius ; Figs 2G , 3I ), 4) scutellar depression (scutal sulcus) densely, coarsely crenulated ( Fig. 1B ) (mainly smooth in Ceylonspathius and Termitospathius ; Figs 2H , 3J ) and 5) first metasomal tergite not petiolate, short and considerably wide ( Figs 1D, F ) (distinctly petiolate in Ceylonspathius and Termitospathius ; Figs 2I, J, K , 3A, L, N ).

Cerritulus also differs from Termitospathius by the marginal (radial) cell of fore wing open apically ( Fig. 1C ) (close in Termitospathius ; Fig. 3K ), first discal (discoidal) cell of fore wing distinctly petiolate anteriorly ( Fig. 1C ) (sessile in Termitospathius ; Fig. 3K ), vein 1m-cu (recurrent) of fore wing antefurcal ( Fig. 1C ) (distinctly postfurcal in Termitospathius ; Fig. 3K ) and subbasal (submedial) cell of hind wing distinctly long ( Fig. 1C ) (short in Termitospathius ; Fig. 3K ). Wings in the single known specimen of Ceylonspathius are broken.

Description. Head. Weakly transverse, its width 1.4 × median length. Ocelli arranged in an equilateral triangle. Antennal sockets situated at upper level of eyes, its maximum diameter 0.8 × distance between sockets. Frons slightly concave medially, without longitudinal carina. Eyes sparsely setose. Occipital carina present and complete. Malar suture absent. Clypeus slightly convex. Hypoclypeal depression round. Postgenal bridge wide. Maxillary palpi 5-segmented; labial palpi short, 3-segmented, third segment 0.7 × longer than second one. Scape of antenna long, wider apically, without apical lobe, its length 1.5 × its apical width. First flagellar segment sub-cylindrical, not curved outer. All basal flagellomeres with placoid sensilla.

Mesosoma. Wide, mostly smooth and polished. Neck of prothorax considerably short. Pronotal collar short but distinct, scrobiculate antero-medially, remaining area smooth to slightly longitudinally striate. Propleural dorsoposterior flange distinct and wide. Mesonotum highly and roundly elevated above pronotum. Notauli present. Scuto-scutellar suture distinct. Metanotum (lateral view) with median, rounded tooth. Prescutellar depression (scutellar sulcus) long and deep, with eight high median carinae. Scutellar disc slightly convex. Precoxal sulcus present but short, shallow, wide and scrobiculate, running along half length of mesopleuron. Prepectal (epicnemial) carina present. Propodeum without delineated areas; lateral tubercles absent. Propodeal spiracles small and round. Metapleural flange distinct, wide, rounded apically.

Wings. Hyaline. Pterostigma of fore wing wide and long. Vein r (radial) arising at middle of pterostigma. Marginal (radial) cell long and wide, opened apically. Veins 2RS and r-m (first and second radiomedial veins) present. Vein 2RS narrower than other veins of fore wing, unsclerotised posteriorly. Vein r-m not sclerotised. Veins r and 3RSa (first and second radial abscissae) forming weakly obtuse angle. Vein 1cu-a (nervellus) postfurcal. Vein 2CUb (parallel) almost interstitial with respect to vein 1CU (second medial abscissa). Second subdiscal (brachial) cell open. Veins 1a and 2a (first and second transverse anal) absent. Hind wing. Vein cu-a (nervellus) present and strongly oblique. Subbasal (submedial) cell long. Vein C+Sc+R (first abscissa of costal vein) almost as long as vein SC+R (second abscissa of costal vein). Vein RS (radial) arising from R vein (third costal abscissa) rather far from vein 1r-m (basal). Radial (marginal) cell widened towards apex of wing. Medial (basal) cell weakly widened towards apex. Subbasal (submedial) cell long.

Legs. Femora considerably thick and wide, with a distinctly rounded apical protuberance. All tibiae strongly curved in basal quarters, flat and rather wide. Fore tibia with a row of at least eight spines. All basitarsi considerably short, its segments subcylindrical. Hind coxa rounded basoventrally, without tubercle. Hind tibial spurs short, slightly curved and pilose; inner spur about 0.5 × as long as hind basitarsus. Basitarsus of hind tarsus 0.25 × as long as second to fifth segments combined. Claws simple and curved, widened basally.

Metasoma. First tergite not petiolate, short and wide, slightly widened basally. Acrosternite (basal sternite) of first segment short, about 0.25 × as long as first tergite. Dorsope of first tergite very small, almost indistinct; basolateral lobes absent. Second suture indistinct. Second tergite without areas or furrows. Second and succeeding tergites without separate laterotergites (epipleura). All tergites sparsely setose. Ovipositor as long as metasoma, apically with two small dorsal nodes, its tip strongly sclerotised; ovipositor sheaths considerably wide, swollen.

Hosts. Unknown.

Distribution. Only known for French Guiana.

Etymology. The name of this genus (from Latin cerritulus = strange) refers to its unusual external morphology with respect to all currently known genera from American continent.

Comments. The new species described below shares various external morphological features with the species assigned to Ceylonspathius and Termitospathius (see diagnosis), which were collected inside termite nests. These morphological features have not been observed on other members of Doryctinae . Therefore, it could be possible that the species described here also has the same termitophilous habits that the species of the above two Asian genera.

Cerritulus shares wing venation features with Embobracon van Achterberg, 1995 , described from Panama ( van Achterberg, 1995). However, Cerritulus distinctly differs from the latter genus in several other external morphological features, including the structure and shape of legs, structure of the first metasomal tergite, presence of precoxal sulcus and sternauli and presence of vein SC+R (second abscissa of costal vein) in the hind wing.

Figures

FIGURE 1. Cerritulus forticrura gen. et sp. nov. (holotype, female). A, Habitus, lateral view. B, Head and mesosoma, dorsal view. C, Fore and hind wings. D, Head and mesosoma, lateral view. E, Head, front view. F, Mesosoma, dorsal view; G, Fore leg, anterior view. H, Legs, lateral view.

FIGURE 2. Ceylonspathius nixoni Belokobylskij, 2002 (holotype, female). A, Habitus, lateral view. B, Basal segments of antenna. C, Head, dorsal view. D, Head, front view. E, Fore femur and tibia. F, Hind femur and tibia. G, Mesosoma, lateral view. H, Mesosoma, dorsal view. I, Metasoma, lateral view. J, Metasoma, dorsal view. K, First metasomal tergite, dorsal view. L, Ovipositor and sheath, lateral view.

FIGURE 3. Termitospathius sumatranus Belokobylskij, 2002 (holotype, female). A, Habitus, lateral view. B, Apical segments of antenna. C, Basal segments of antenna. D, Head, dorsal view. E, Head, front view. F, Fore femur and tibia. G, Hind tibia. H, Hind femur. I, Mesosoma, lateral view. J, Mesosoma, dorsal view. K, Wings. L, First metasomal tergite, dorsal view. M, Metasoma, dorsal view. N, Metasoma, lateral view. O, Apical part of ovipositor. P, Apical part of ovipositor sheath, lateral view.