Sinaphaenops wangorum, Ueno et Ran, 1998

Luo, Xiao-Zhu, Wipfler, Benjamin, Ribera, Ignacio, Liang, Hong-Bin, Tian, Ming-Yi, Ge, Si-Qin & Beutel, Rolf Georg, 2018, The cephalic morphology of free-living and cave-dwelling species of trechine ground beetles from China (Coleoptera, Carabidae), Organisms Diversity & Evolution (New York, N. Y.) 18 (1), pp. 125-142 : 127

Sinaphaenops wangorum

External head structures

The head is prognathous and club-shaped. It is strongly elongated and narrow, almost three times as long as the maximum width at the eyeless ocular region. In dorsal view, it is almost parallel-sided over a distance posterior to the antennal insertions, then narrowed, and formed an elongate constriction anterior to the slightly widened and rounded temples, which again narrow towards the foramen occipitale. The head in lateral view appears slightly flattened, with the maximum height in the middle region. The coloration is dark brown and the cuticle smooth and largely glabrous, with only a few long setae inserted on the head capsule. The compound eyes are completely missing without visible traces.

The clypeus (cl; Fig. 1a ) is about as long as the labrum and of rhomboid shape. Its anterior edge is very slightly convex and narrower than the posterior part of the labrum. The oblique anterolateral edges are straight and diverging posteriorly, where they meet the secondary (dorsal) mandibular articulation. Posterolaterally, the clypeus is delimited by fissure-shaped anterior tentorial grooves, which are connected by a very slightly curved, transverse clypeofrontal furrow. Four long setae inserted on the middle clypeal region are arranged in a transverse row. The protuberances of the secondary mandibular joint (smdj; Fig. 5a, b ) are distinctly exposed at the lateral clypeal angles, in a distinct notch at the anterior end of the anterior tentorial grooves. The anterolateral antennal foramen is largely covered by a rounded frontal lobe bearing a shorter and a long seta. The frontal sutures and the coronal suture are absent. Paired dorsal longitudinal furrows (ff; Fig. 1a ; Jeannel 1926: sillons frontaux) originate on the middle clypeal region and continue on the anterior frontal area. Anteriorly, they are parallel-sided, then slightly converging towards each other, and then diverging, forming an even curve before obliterating at about half-length of the head capsule. Much shorter longitudinal furrows are recognizable between the anterior tentorial grooves and antennal articulation, with posterior parts diverging before they obliterate. The gula (gu; Fig. 1c ) is very narrow and strongly elongated, more than two thirds as long as the head capsule on the dorsal side. It is anteriorly delimited by rather indistinct posterior tentorial pits. Nearly parallel-sided gular ridges (gur; Figs. 2a , 4a , and 9a ) are faintly recognizable externally. They are anteriorly continuous with slightly oblique lines posterolaterally delimiting the submentum. Posteriorly, they diverge close to very narrow foramen occipitale and obliterate before they reach it.

Figures

Fig. 1 Head habitus of the studied specimens. a–c Dorsal, lateral, and ventral views of S. wangorum. d–f Dorsal, lateral, and ventral views of B sp. g–i Dorsal, lateral, and ventral views of T.perroti. atp anterior tentorial pit, ce compound eye, cfs clypeofrontal suture, cirl circular line, cl

Fig. 5 Mandibles of the studies specimens. a Left and right mandibles of S. wangorum. b Right and left mandibles of S. wangorum. c Left and right mandibles of T. perroti. d Right and left mandibles of T. perroti. e Left and right mandibles of B. sp. f Right and left mandibles of Bembidion sp. a, c, e Dorsal view. b, d, f Ventral view. ai apical incisor, bb basal brush, cue cutting edge, met mesal tooth, pmdj primary mandibular joint, smdj secondary mandibular joint, vm ventral microtrichia

Fig. 2 3D reconstructions of tentoriums (a, b, c) and nervous + digestive systems (d, e, f). a, d S. wangorum. b, e T. perroti. c, f B. sp. Upper part of each image: dorsal view; lower part of each image: ventral view. ata anterior tentorial arm, cer cerebrum, cn connective, dta dorsal tentorial arm, fg frontal ganglion, gur gular ridge, p pharynx, tb tentorial bridge

Fig. 4 3D reconstructions of antennal muscles of S. wangorum (a) and T. perroti (b) and labial muscles of S. wangorum (c) and T. perroti (d). Upper part of each image: dorsal view; lower part of each image: ventral view. ata anterior tentorial arm, dta dorsal tentorial arm, gur gular ridge, mt mentum, pg palpiger

Fig. 9 Pharyngeal and labial muscles, lateral view. a S. wangorum. b T. perroti. c B. sp. gur gular ridge, lr labrum, mp maxillary palp, p pharynx