Trechiotes perroti, Jeannel, 1954

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 : 132

Trechiotes perroti

External head structures

The head is wedge-shaped in lateral view and only slightly longer than wide, about 1.2 times as long as the maximum width at the ocular region. The coloration is blackish brown, with only a few long or short setae inserted on the head capsule. The compound eyes (ce; Figs. 1g and 2e ) are large and protruding laterally. The clypeus is almost as long as the labrum. Deeply impressed paired dorsal furrows (ff; Fig. 1g ) are distinctly diverging anteriorly and posteriorly. Oblique longitudinal furrows extend between the secondary mandibular joint (smdj; Fig. 5c, d ) and the anteromesal corner of the compound eyes. A circular line (cirl; Fig. 1g ) on the caudal third of the head is about one fifth as long as the width of the posterior head capsule and obliterated ventrally. The head is retracted into the thorax posterior to it. On the ventral side, the gula (gu; Fig. 1i ) is relatively long and broad, about one half as long as the head capsule, with a maximum width of about one third of the width between the eyes. The curved gular ridges (gur; Figs. 2b , 4b , and 9b ) are scarcely recognizable externally.

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. 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. 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. 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