Ictistygnina Champion, 1916

Telnov, Dmitry, 2024, On the taxonomy of some South American and Australo-Pacific Anthicidae Latreille, 1819 (Coleoptera) with new subfamily and tribe-rank synonymies, Zootaxa 5501 (3), pp. 401-424 : 412-414

Ictistygnina Champion, 1916

Champion (1916: 190), type species Ictistygnina filicornis Champion, 1916 [original designation].

The genus was originally placed in the Lagriidae Latreille, 1825 ( Champion 1916), now a subfamily of Tenebrionidae Latreille, 1802 in accordance with the present classification ( Bouchard et al. 2021). Current position of the genus in Ictistygnini was first proposed by Borchmann (1936: 534‒535; as ‘Ictistygninae’), which was followed subsequently by several authors. The genus is considered to be monotypic: Ictistygnina filicornis remains known only from the state of Rio de Janeiro in southern Brazil ( Champion 1916).

Champion (1916: 190‒191) defined Ictistygnina based on the following set of morphological features: ‘narrowly closed anterior coxal cavities’, ‘extremely elongate antennae, large eyes’, ‘difference in the size of the eyes in the two sexes’ and ‘very small second joint to the unusually elongate, filiform antennae’. The new genus was considered to exhibit similarities with the Australian Ictistygnini (in that time sense) genus Ictistygna Pascoe, 1866 as well as the Calopodinae A. Costa, 1852 genus Calopus Fabricius, 1775 ( Oedemeridae Latreille, 1810 ) ( Champion 1916). Borchmann (1936: 534) erected a new subfamily ‘Ictistygninae’ in what was Lagriidae at that time, and which was downgraded to the rank of a tribe, Ictistygnini , in Eurygeniinae , Anthicidae by Abdullah (1969: 340), where it remains up to now ( Chandler 2010).

In this paper I do not aim to review all features of eurygeniine genera or provide a more comprehensive comparative diagnosis for Ictistygnina but provide only the redescription of this group.

Supplementary description of Ictistygnina ( Fig. 5 )

Type material examined. Syntype 1♂ BMNH ( Fig. 5A‒B ): Fry RioJan [handwritten] // Fry Coll. 1905.100. [printed] // Sp. figured. [printed] // ♂ [printed] // Ictistygnina filicornis, Ch. [handwritten] // dorsal BM 17 [handwritten] // SYNTYPE [printed, label circular, blue frame]; syntype 1♀ BMNH ( Fig. 5C‒D ): Fry RioJano. [handwritten] // Fry Coll. 1905.100. [printed] // ♀ [printed] // Ictistygnina filicornis, Ch. [handwritten] // SYNTYPE [printed, label circular, blue frame]; syntype 1♂ BMNH: Fry RioJan [handwritten] // 2992 [handwritten] // Fry Coll. 1905.100. [printed] // ♂ [printed] // Ictistygnina filicornis, Ch. [handwritten] // SYNTYPE [printed, label circular, blue frame].

Frontoclypeal suture not observed. Mandible apex unidentate, rounded (broadly scooped). Right mandible with an indistinct indentation at inner edge at some distance from apex. Terminal maxillary palpomere subcultriform. Compound eye nearly holoptic, occupying nearly whole head side posterior to antennal insertion, shallowly notched at anterior margin at antennal insertion; posterior eye margin subtruncate to shallowly emarginate.Antennal insertion touching anterior margin of a compound eye in male, slightly distant from it in female. Antenna extraordinarily long and slender, in male extending beyond elytral apex when directed posteriad, in female extending to slightly beyond metacoxal cavity. Antennomeres 3‒11 with moderately long, dense, suberect setae. Antennomere two strongly shortened, slightly transverse to about as long as wide. Terminal antennomere not modified, long and slender. Cranial ‘neck’ about one third head width across compound eyes. Pronotum about as wide as head across compound eyes, about as long (excluding anterior flange) as wide (about 1.2× as long as wide including anterior flange), lateral margins broadly rounded. Anterior pronotal flange distinct and broad dorsally, nearly same wide ventrally as dorsally, dorsally somewhat elevated (compared to a pronotal disc) and projected anteriad to conceal most of cranial ‘neck’. Suture of anterior flange incision-like deep and narrow laterally, shallow and rather broad dorsally. Basal pronotal margin dorsally with a deep and rather wide sulcus which widens on lateral margins. Elytra flattened, strongly elongate. Epipleuron narrow, incomplete. At least distal half of each tibia spinose. Tibial terminal spurs paired, elongate, straight to barely curved, margins smooth, apically acutely angulate. Penultimate tarsomere short, distinctly bilobate. Pretarsal claws rather long, each with an indistinct basal indentation. Procoxae elongate, contiguous. Procoxal cavity narrowly open externally behind (propleura narrowly separated or come in contact or even slightly overlap depending on the condition of the specimen but are never fused together in the sense used in the contemporary morphological terminology of Tenebrionoidea), closed internally. Postcoxal plate not present. Mesanepisterna meet in front of a triangular mesoventrite, shortly produced anteriorly at place of meeting, building a flat, acutely angulate anterior projection, with a distinct short longitudinal suture at place of meeting. Mesanepisternum expanded laterally, separated from mesoventrite by a distinct, nearly straight suture; a distinct, flat, rugose ventral sulcus separates anterior portion of mesanepisternum from its main portion; less prominent postmarginal and distinct accessory carina present, separated by ventral sulcus (both carinae, separated, by much narrower ventral sulcus, appear also in Ictistygna ); procoxal rest not present; area between anterior and main part of mesanepisternum glossy and glabrous, slightly globose in ventral aspect; posterior margin of mesanepisternum with a row of long, dense setae which continues over along posterior and lateral (external) margins of mesepimeron; most of mesanepisternum glabrous, with sporadic setae. Intercoxal process of mesoventrite narrow, long, elevated in ventral aspect, meets an acute anterior process of metaventrite at about posterior third of mesocoxal cavity; mesocoxal cavities separated. Mesepimeron distinct, broadly subtriangular; long setae not visible in dorsal view. Metaventrite longer than mesosternum, discrimen not observed. Metanepisternum long, narrow. Metacoxal cavities narrowly separated by an acute anterior process of first visible abdominal segment. Male morphological sternite VII emarginate at posterior margin.

Sexual dimorphism. Ictistygnina exhibits a strong sexual dimorphism ( Fig. 5 ). Female frons is comparatively wider, compound eyes are smaller (and, therefore, cranial ‘neck’ is wider than that of male, about half head width, postocular area longer than in male. Female antenna significantly shorter than that of male, not extending to elytral apex. Female terminal maxillary palpomere is less elongate, more strongly securiform (but still subcultriform in the sense of the commonly used anthicid morphological terminology).

Figures

FIGURE 5. Ictistygnina filicornis Champion, 1916. A—Syntype ♂, habitus, dorsal view; B—ditto, forebody, antero-dorsal view: C—Syntype ♀, habitus, dorsal view; D—ditto, forebody, dorsal view [not to scale].