(Proceedings submission caseby-case

434 PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES
Series 4, Volume 63, No. 12
Kavanaugh et al. (2014) suggested that the Gaoligong Shan region may have been an area of
differentiation, speciation and origin of montane elements from which, rather than to which, at least
some of the species that now range more broadly subsequently spread. This hypothesis was based
on meager evidence provided by the zabrine fauna of the Gaoligong Shan, but also on geologic evidence.
The Hengduan Mountains date their origins to the late Mesozoic, whereas the uplift of the
Himalayan Ranges and Qinghai-Xizang Plateau began later, in the early Cenozoic (Chaplin 2005).
Hence the biota of the Gaoligong Shan region probably predates that of these other areas as well.
The trechine fauna of the region supports this hypothesis even more strongly. The occurrence of
four precinctive genera and one apparently precinctive subgenus of small, flightless beetles, two of
which are represented by two and seven species, respectively, suggests differentiation and diversification
within the region. The occurrence of another nine likely precinctive species in other genera
suggests speciation in situ. Finally, even the four species with ranges extended beyond the
Gaoligong Shan region all have those ranges either centered on the region of anchored there. As
with the zabrines, a better understanding of phylogenetic relationships among the Gaoligong Shan,
Eurasian and Oriental trechinespecies and genera is required in order to test this hypothesis, and
such an analysis has not yet been undertaken.
REGIONAL GEOGRAPHICAL AND ALTITUDINAL DISTRIBUTION PATTERNS.— within the
Gaoligong Shan study area, most of the trechine species represented are narrowly distributed, both
geographically and altitudinally. This is not surprising given the high percentage (72%) of species
with flightless adults and their preferences for moist, undisturbed habitats. Such areas are restricted
within the region mainly to remaining forested areas at low to middle elevations and alpine
meadows, moist tundra, stable talus slopes, stream edges and bamboo and Rhododendron thickets
at higher elevations. Many such areas in the region are separated from each other by deep valleys
and, increasingly, by disturbance associated with agriculture and human habitation. while human
disturbance is relatively recent, topographic diversity of the region has been developing since the
Miocene (Chaplin 2005).
The chart in Fig. 46 summarizes the recorded regional distributions of the species with respect
to our project-designated Core Areas (see Fig. 3); and the recorded altitudinal ranges for each
species are shown in Fig. 47. These charts clearly demonstrate the relatively narrow geographical
and altitudinal ranges of most of the trechine species occurring in the region. This is especially
apparent from comparisons with the ranges of zabrine species in the same area (see Kavanaugh et
al. 2014, Figs. 28 and 29). Among the 13 zabrine species in the fauna, one is recorded from all 7
Core Areas, one from 6 Core Areas (all except 5) and three from four or five Core areas; and most
of these species are likely to occur in all seven Core Areas. In contrast, only one species, Trechus
indicus, is recorded from as many as four Core Areas (1, 3, 6 and 7) and also has a relatively broad
known altitudinal range (1230 to 2486 m). Given that it is recorded from the northernmost and
southernmost core areas, as well as from both eastern and western slopes of the Gaoligong Shan,
it is likely to be found in additional, if not all, core areas with further sampling. Only one additional
species, Perileptus imaicus, is recorded from as many as three Core Areas (2, 6 and 7) and also has
a broad known altitudinal range (from 680 to 2030 m). Like T.indicus, it is recorded from both
northernmost and southernmost core areas and from both slopes of the mountain range, so it is likely
to be more widespread in the region than is presently known, at low to middle elevations. Five
additional species are recorded from as many as two core areas: Perileptus pusilloides (Core Areas
6 and 7, known altitudinal range from 680 to 1105 m); Agonotrechus fugongensis (Core Areas 2
and 3, known altitudinal range from 2300 to 2530 m); A.wuyipeng (core areas 2 and 3, known altitudinal
range from 2687 to 2770 m); Queinnectrechus balli (Core Areas 1 and 2, known altitudinal
range from 3300 to 3750 m); and Trechepaphiopsis unisetosa (Core Areas 4 and 5, known altitu-