Socotrorhinus, Skuhrovec & Kresl, 2014

Skuhrovec, Jiří & Kresl, Petr, 2014, A new genus and species of Rhinocartini (Coleoptera: Attelabidae: Rhynchitinae) from Socotra Island, Acta Entomologica Musei Nationalis Pragae 54, pp. 283-294 : 285-287

Socotrorhinus gen. nov.

( Figs1A, D–E ; 2A–M )

Type species. Socotrorhinus boswelliae sp. nov., by present designation.

Diagnosis. Body length 2.8 to 4.2 mm (without rostrum); temples distinctly widened backwards; rostrum distinctly longer than its base width in females (ratio = 4.00–4.88), less so in males (ratio = 2.75–3.50), distinctly widened from antennal connection towards apex, in lateral view distinctly curved, bent; scrobes indistinct and shallow, not visible in dorsal view, poorly visible in lateral view as a longitudinal furrow along whole length of rostrum on its lower side; labrum indistinct, fused with clypeus; mandibles without mola; relatively slender; with edges passing each other like scissor blade; on outer side without tooth, on inner side with one blunt tooth before apex; maxilla with distinct galea and lacinia; maxillary palpi distinct, compact, four-segmented; prementum narrow, moderately sclerotized; ligula distinct; antennae inserted near base of rostrum, antennae long, slender, straight, non-geniculate; procoxal cavities relatively shallow; notosternal suture distinct, narrowly open; procoxae contiguous, subconical, prominent; prosternum in front of procoxae relatively narrow; prosternellum posterior to procoxae distinct; scutellum small, squared, not extended above elytra; elytra with distinct humeral angles; elytral striae distinctly larger and deeper than punctures on pronotum, forming 10 distinct rows; mesocoxal cavities laterally open; mesocoxae semiglobular, mesoventral process very narrow; metacoxae distinctly separated, short and wide, oriented dorsolaterad; all femora simple, edentate; tibiae apically widened; apically with spurs and without uncus on all pairs; claws thick, wide sickle-shaped; abdominal ventrites I and II fused, slightly visible small sinuosity in midlength; fused ventrites I and II distinctly longer than ventrite III–V; suture between abdominal ventrites I and II slightly visible as sinuosity; next three sutures straight and deep; apodeme of penis more than twice the length of median lobe; tegmen without fenestrae, its terminal plate elongated and tapered apically bearing a few long setae; sternite VIII in females with moderately long apodeme, without distinct lateral arms, terminated just inside plate, plate spacious and heart-formed, with apical margin bearing several distinct setae, weakly sclerotised; gonocoxites of ovipositor with long apical styli bearing setae.

Description. See the description of species.

Etymology. The name is derived from the name of Socotra Island (Socotr [o]-) and the component - rhinus (= having a nose; Latin, from Greek word rhis = a nose), characteristic for many attelabid genera; gender masculine.

Included taxa. Genus is described as monotypic.

Taxonomic assignment of the tribe and differential diagnosis of genus. VOSS (1931) in his tribal key of Rhynchitinae stated that the main differential character of the tribe Rhinocartini is random elytral striae (not arranged in rows). Ten years later, VOSS (1941) included the genera Proteugnamptus and Rhinocartus in the tribe Rhinocartini , despite the genus Proteugnamptus having elytral striae in rows. The tribe Rhinocartini sensu VOSS (1941) is presented as a group positioned between Auletini and Rhynchitini but also with some similarities to the tribe Eugnamptini . RIEDEL (2014) considered the tribe to be incertae sedis within the subfamily Rhynchitinae . LEGALOV (2003, 2007) established a supertribe Rhinocartitae and introduced many new taxa, including four new tribes (i.e. Auletorhinini , Proteugnamptini, Sayrevilleini and Vossicartini ). However the definition of these tribes is rather poor and based on variable characters; e.g. the shape and the length of rostrum is highly sexually dimorphic character (see Sexual dimorphism below, Table 1). We accepted the classification by RIEDEL (2014) (see below for more details) and the main tribal differential character from the supertribal key by LEGALOV (2007) instead of the key by VOSS (1931).

The position of the tribe Auletorhinini from LEGALOV (2007) is absolutely enigmatic. LE- GALOV (2007) stated that a mandible without tooth on external edge is the main differential character of the supertribe Rhinocartitae , but later stated that representatives of the tribe Auletorhinini have a mandible with a small tooth on external edge. We accepted the classification by RIEDEL (2014), who presented the genus Auletorhinus Voss, 1935 in the tribe Auletini .

The tribe Sayrevilleini sensu LEGALOV (2007) is currently considered a separate fossil subfamily Sayrevilleinae Legalov, 2003 characterized by possessing mandibles with an external cutting edge and an inner blunt edge ( RIEDEL et al. 2012). This subfamily is recently placed in the family Attelabidae (s.l.), although some characters may suggest a possible relationship with the ‘higher taxa in weevils’ comprising Caridae , Brentidae , and Curculionidae ( RIEDEL et al. 2012) . The recent genera included in Sayrevilleini by LEGALOV (2007) will probably need to be transferred to another group of Rhinocartini , which is, however, beyond the scope of this paper.

The differential diagnosis of the remaining three tribes (Proteugnamptini, Rhinocartini , and Vossicartini ) of Legalov’s supertribe Rhinocartitae , and the new genus Socotrorhinus gen. nov. are presented in Table 1. Different states of characters are indicated for some taxonomic ranks, and it is almost impossible to determine the correct status, e.g., Proteugnamptini with short and wide rostrum, but its subtribe Eosalacina with thin and long rostrum; or Rhinocartini with long and narrow rostrum, but Rhinocartus tessmanni Voss, 1922 with short and wide rostrum (see Table 1, Fig. 1G ).

The representatives of Proteugnamptini, Rhinocartini and Vossicartini occur in Central and South Africa, including the islands of Madagascar and Réunion. The origin of Socotrorhinus boswelliae sp. nov. will most likely be from one of these tribes/groups. The members of the tribe Vossicartini seem to be the most similar group. However, as the current classification of the whole supertribe Rhinocartitae sensu LEGALOV (2007) is far from perfection, we are not able to postulate relationships between Socotrorhinus gen. nov. and the tribes/genera of the supertribe. Based on the facts mentioned above and in Table 1, we refrain from association of the new genus with any of Legalov’s tribes and place it simply in tribe Rhinocartini sensu RIEDEL (2014) .

racters used by LEGALOV (2007).

Figures

Fig. 1. Differential diagnosis of the new genus and the tribes of Rhinocartitae according to the characters used by LEGALOV (2007): Socotrorhinus gen. nov. (S. boswelliae sp. nov.): A – elytra; D – head with rostrum and antennae, male; E – head with rostrum and antennae, female; Vossicartini (Vossicartus tanzanensis Legalov, 2007): B – elytra; F – head with rostrum and antennae, male; Rhinocartini: (Rhinocartus tessmanni Voss, 1922): C – elytra; G – head with rostrum and antennae, male.

Fig. 2. Socotrorhinus boswelliae sp. nov. Holotype, male (A, H–J), female (K–M): A – habitus, dorsal view; B–G – variation in coloration, dorsal view; H – aedeagus, dorsal and lateral view; I – tegmen; J – spiculum gastrale; K – female sternite VIII; L – spermatheca; M – ovipositor. Scales: 1 mm, scale with * = 2 mm, scale with ** = 0.2 mm.