Borneophanus, Yoshida, Takahiro & Hirowatari, Toshiya, 2018

Yoshida, Takahiro & Hirowatari, Toshiya, 2018, A new genus and species of Brontinae from Borneo (Coleoptera, Silvanidae), ZooKeys 805, pp. 45-57 : 47-49

Borneophanus gen. n.

Type species.

Borneophanus spinosus Yoshida & Hirowatari, sp. n.

Diagnosis.

Among telephanine genera, this new genus shares the following character states with Telephanus , Psammoecus , and Indophanus Pal, 1982: apical maxillary palpomere securiform; apical labial palpomere securiform; scutellary striole absent (some species of Malagasy Telephanus have a scutellary striole). This new genus differs from these genera by the combination of the following character states: distinct pair of longitudinal frontal lines present (absent in Telephanus ); scutellar shield with a transverse carina and excavate posteriorly (flat in Psammoecus ); antennomere IV normal (markedly long, approximately twice as long as combined length of II and III in Indophanus ) ( Thomas and Nearns 2008; Sen Gupta and Pal 1996). In addition, this new genus possesses the following characteristic morphology: the asymmetric shaped antennomere X (somewhat asymmetric in Bolianus ); the sharply protruding elytral apices; the non-folded internal sac; the partly coiled flagellum; and the very long and rolled up spermathecal duct.

Description.

Body densely covered with pubescence. Head (Figs 1-3) with indistinct frontoclypeal suture, with distinct pair of longitudinal frontal lines; eyes somewhat small, hemispherical; temples moderate in size; labrum (Fig. 3B) rectangular; antenna (Fig. 3A) long, with long scape; antennomere X asymmetrically enlarged; mandible (Fig. 3C, D) tridentate, with a ventral tooth and an inner lateral tooth near apex, ventrally with asperities near the inner tooth, with fine, random punctation, dorsolaterally with medium length to long setae, dorsally with a mycangium near base; maxilla (Fig. 3E) with lacinia and galea; galea divided into distigalea and basigalea; maxillary palp 4-segmented; apical palpomere securiform, dorsally and largely with digitiform sensilla on middle of apical palpomere; labium (Fig. 3F) divided from ligula; prementum widened distally; articulation of palps tight; labial palp 3-segmented; palpomere 2 extended outwards strongly and broadly, with large distal area; palpomere 3 securiform, strongly widened distally; mentum widened proximally, widest near base. Pronotum (Figs 1A, 2) without teeth on lateral margins, with rounded anterior angles, densely covered with setae of various lengths, without microsculpture. Thoracic ventrites (Fig. 1B) with narrowly separated pro- and mesocoxal cavities, with somewhat widely separated metacoxal cavities. Scutellar shield (Figs 1A, 2) with a transverse carina, excavate posteriorly. Legs (Figs 1, 4A, B) somewhat thin; tarsomeres 2 and 3 lobed, not bilobed. Abdominal ventrites (Fig. 4A) with somewhat wide intercoxal process, without sexual dimorphism. Elytra (Figs 1A, 2) long, without scutellary striole; lateral margins very narrowly explanate; apices somewhat elongate and narrowly rounded, with short setae on interstices. Male tergite and sternite VIII square and not divided (Fig. 4D); spiculum gastrale (Fig. 4E) thin and Y-shaped, with branches covered with membrane; median lobe (Fig. 4H) without setae; internal sac (Fig. 4H) not folded, with partly coiled flagellum, exposed around apex of median lobe; parameres (Fig. 4F, G) flat. Female with elongate gonostyli (Fig. 6B); gonocoxite (Fig. 6B) with setae of various lengths; spermathecal duct (Figs 6A, 7A) connected to basal portion of bursa copulatrix, very long, rolled up and forming large ellipsoid.

Distribution.

Malaysia (Sabah and Sarawak states).

Etymology.

The new genus name is composed of two words, the locality, Borneo where this new genus was collected, and the Greek phanos meaning bright.

Remarks.

We found sensilla, called digitiform sensilla, each located in a groove on the dorsum of the apical maxillary palpomere. Lawrence and Ślipiński (2013) stated that such sensilla on apical maxillary palpomere may be present in adephagan and polyphagan beetles, but they have never been described in Silvanidae . We confirmed these in genera possessing securiform apical maxillary palpomeres ( Telephanini : Psammoecus dentatus Grouvelle, 1883; Telephanus paradoxus Reitter, 1874; Cryptamorpha desjardinsi ( Guérin-Méneville, 1844), Brontini : Australohyliota mcleayi (Olliff, 1885), Cucujidae : Cucujus bicolor Smith, 1851), although, these sensilla vary in the position and size of the area among the genera (Fig. 5).

The spermathecal duct of this new genus is extremely long, likely correlated to the partly coiled flagellum of the male genitalia. However, among Telephanini , female genital structures have not been studied. For comparison, we examined the female genitalia of P. dentatus (Fig. 7B) and C. desjardinsi (Fig. 7C) and found that their sper mathecal ducts are apparently shorter than in the new genus. Additionally, we found further differences in the female genitalia (e.g., gonostyli; spermatheca), thus, future comprehensive study of telephanine female genitalia seems likely to provide some useful taxonomic characters and/or their phylogenetic insights.

The biology of the new genus is unknown except for the information that one paratype of the type series was collected by beating foliage. This new genus possesses lobed tarsomeres which are shared by most telephanines and seem to be related to the ecology living on dead leaves ( Thomas 1984), thus, they may have ordinary habits of telephanine beetles.