(Proceedings submission caseby-case

DEUVE ET AL.: CARABID BEETLE FAUNA OF THE GAOLIGONG MOUNTAINS 379
tor [1 female; CAS]. This record extends the range of E. fragilis in Sichuan. The discovery of
E.fragilis in the northern Gaoligong Shan region, in western Yunnan Province, extends its known
range an additional 260 km Sw.
Genus Trechus Clairville, 1806
Trechus Clairville, 1806:22.
TYPE SPECIES.— Carabus rubens, Clairville, 1806 [nec Fabricius, 1801] (= Carabus quadristriatus
Schrank, 1781), designated by Blanchard (in Audouin et al. 1841, plate 25). See also comments
on type species by Bousquet (2012: 505).
DIAGNOSIS.— Adults of this genus (Fig. 17-25) can be recognized by the following combination
of character states: size very small to small for family (BL = 2.5 to 7.0 mm), fully-winged or
apterous, eyes large and projected or reduced, with some members eyeless; body color varied, from
pale yellowish-tan to black; body form varied, compact and convex in most members, more slender
and depressed in some members; labrum with anterior margin concave; right mandible bidentate
or tridentate, but with the premolar fused with the retinaculum; submentum free, not fused with
mentum, with six setae anteriorly in most members; pronotum with disc glabrous, two pairs of
setae lateral present, one each side near middle and near basal angle; elytra with discal striae distinctly
impressed and complete or more or less effaced, recurrent stria distinct, discal setae only on
interval 3, near or in stria 3 in most members, two setae present in most members, but with more,
one or none present in a few members; preapical seta present near discal stria 2 or absent, in a few
members present and inserted more anteriorly in a discal position on interval 3 near stria 2 or 3;
umbilicate setae of the humeral group equally spaced; protibiae longitudinally furrowed or not.
COMMENTS.— As can be inferred from the above diagnosis, the large genus Trechus is
markedly heterogeneous and probably polyphyletic. This hypothesis of polyphyletism has been
corroborated by early results of analyzes of nucleic acid sequences data (Faille et al. 2010, 2013a).
Among morphological features commonly used in comparative systematic studies of genus
Trechus, two deserve special attention because they have allowed us to distinguish three new genera,
described below, among species occuring in the Gaoligong Shan Mountains. These features
include (1) the presence and position or the absence of a preapical elytral seta, and (2) the dentition
of the mandibles.
1) Presenceandpositionofpreapicalseta: The primary elytral discal setae of carabid beetles
are located on the odd intervals: 3, 5, 7 and 9 (Jeannel 1941). Jeannel named the setae of interval
9 the “sérieombiliquée”, the umbilicate series.
In members of subtribe Trechina, the umbilicate series includes a group of four consecutive
humeral setae, a middle group of two consecutive setae, and two more isolated posterior setae; discal
setae are absent from interval 7; they occur on interval 5 in some members (eg., in Trechiama
Jeannel (1927) and Epaphiopsis Uéno (1953)). In most members, there are three setae on interval
3, inserted subbasally, near the middle and preapically, respectively. Although this can be considered
the basic number for members of the subtribe, but this number is varied, more or less.
In members of genus Trechus, there are typically three discal setae in interval 3, the first two
inserted in or against stria 3, the third in prepical position inserted against stria 2. In some species
(eg., Trechus perissus Andrewes (1936), described from Sikkim (see Uéno 1972a), or Trechus
setitemporalis Deuve (2005), described from southern Xizang Autonomous Region), an additional
discal seta is present, inserted next to stria 3, between the middle and preapical setae. In a few
species, it is the preapical seta itself, typically inserted preapically against stria 2 that is advanced
anteriorly to a discal position on the 3rd interval and inserted either in the center of the interval or