Proceratium longmenense Xu, 2006

Staab, Michael, Garcia, Francisco Hita, Liu, Cong, Xu, Zheng-Hui & Economo, Evan P., 2018, Systematics of the ant genus Proceratium Roger (Hymenoptera, Formicidae, Proceratiinae) in China - with descriptions of three new species based on micro-CT enhanced next-generation-morphology, ZooKeys 770, pp. 137-192 : 137

Proceratium longmenense Xu, 2006 Figs 6A, 14, 25

Proceratium longmenense Xu, 2006: 154 (w.), China

Type material.

Holotype. Pinned worker from CHINA, Yunnan Province, Kunming City, Xishan Mountain Forest Park, Longmen, subtropical evergreen broadleaf forest, 2050 m asl, 5-V-2001, leg. Zhenghui Xu, No. A00514 (in SWFU) [examined].

Diagnosis.

Proceratium longmenense differs from the other members of the P. itoi clade by the following character combination: medium-sized species (TL 3.2); sides of head and vertex weakly convex, almost straight; head (CI 85) and scapes (SI 68) relatively long; frontal carinae developed, their lateral lamellae relatively narrow, touching each other at their anteriormost level, not conspicuously broader above antennal insertions; posterodorsal corners of the propodeum broadly angular; posterior face of petiolar node in profile shorter and steeper than anterior face; petiole almost as broad as long (DPeI 91); subpetiolar process developed, roughly trapezoid; in addition to dense pubescence erect hairs present on dorsal surface of body, but only sparsely on head, scapes without erect hairs.

Distribution and ecology.

This species is only known from the holotype that was collected in subtropical evergreen broadleaved forest at 2050 m asl. No direct observations of biology and natural history are available for P. longmenense .

Taxonomic notes.

The unique hair patterns separate P. longmenense from the other species of the P. itoi clade. Proceratium williamsi and P. zhaoi have no erect hairs that protrude from the dense pubescence on the dorsal surface of body (hairs present in P. longmenense , but relatively sparsely, especially on head). All other species ( P. bruelheidei , P. itoi , P. kepingmai , P. malesianum ) have also such hairs on the scapes (absent on scapes in P. longmenense ). In addition to hairs, which may be worn down in old specimens, P. longmenense is unique by the relatively long scapes (SI 68) combined with the relatively narrow head (CI 85). Among the other Chinese P. itoi clade species, it differs furthermore from P. zhaoi in size (WL 0.97; WL<80 in P. zhaoi ), from P. itoi by the shape of the posterodorsal corners of the propodeum (broadly angular; rounded in P. itoi ), and from P. bruelheidei , P. itoi , and P. kepingmai by the lamellae of the frontal carinae (touching each other at their anteriormost level; separated in the other three species).