Tetragonoderus elegans Andrewes
Creators: name: Kavanaugh, David H.
name: Cueva-Dabkoski, Mollie
name: Liang, Hongbin
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Tetragonoderus
Tetragonoderus elegans

description: Tetragonoderus elegans Andrewes
Figures 5, 6, 10, 13C, 14C, 15C, 16C, 17C, 19A-B, 21, and 23.
Tetragonoderus elegans Andrewes, 1931:524. HOLOTYPE, a female, in NHMUK. Type locality: India, Uttarakhand, Dehradun, Bindal River. Csiki (1932:1296).
Cyclicus elegans (Andrewes), Lorenz 2005:453.
Diagnosis. Adults of T. elegans can be distinguished from those of other cyclosomine species in the study area by the following combination of character states: Body size medium for genus, BL males = 4.4 to 5.2 mm, females 4.6 to 5.6 mm; pronotum dark, black or piceous, with distinct greenish or bronze metallic reflection, slightly narrowed basally (ratio PWM/PWB =1.13 to 1.20); elytral color pattern as in Fig. 10A, with dark areas more expansive; connection between medial portion of the basal dark band and humeral portion broader, at least one-quarter length of the humeral portion; middle band with portion between anterior and posterior dark edges distinctly darker (orange-brown) than remainder of pale elytral areas; femora pale tan; pronotum widest at or anterior to middle, slightly narrowed basally (ratio PWM/PWB =1.13 to 1.20); elytra slightly to distinctly and obliquely truncate apically; front tarsomeres 1 to 3 without lateral expansions (Figs. 14 CA, 15C); male with middle tarsomeres 1 to 4 (Fig. 16C) distinctly wider than in female and with pads of adhesive setae ventrally (Fig. 17C); median lobe of male genitalia (Fig. 19A,B) with apical lamella long and bent ventrally, internal sac with several large and conspicuous spines.
In the study area, specimens of T. elegans (Fig. 10A) might be confused with those of T. punctatus (Fig. 12A) and also those of T. microthorax (Fig. 20), although the latter has not yet been recorded from the study area. Refer to the key for features distinguishing members of these three species and the Diagnosis section for T. punctatus below for further discussion of these differences.
Habitat distribution. Within the study area, members of this species have been found only on open sandy shores of medium- to large-sized rivers, where they remain buried in the sand or under cover during daylight hours and are active on the sand surface in moist areas at night. A few specimens have been collected during the day from under small stones and drift debris in the same habitat. At night, these beetles are active in upper beach areas, where zones of slightly moist and dry sand meet (Fig. 21). Members of this species were found at night together with T. punctatus adults at two localities along the Longchuan River and in daytime under stones in the same habitat with T. parviculus adults. Within the Gaoligong Shan region, this species occurs at relatively low elevations, below 2000 m, with our records documenting its occurrence in the 1185 to 1890 m range.
Geographical distribution within the Gaoligong Shan. Fig. 10B. We examined a total of 107 specimens (42 males and 65 females) from the following localities: Fugong County: Shangpa Township (west bank of Nu Jiang, 26.90668°/98.86339°, 1185 m, 13 October 2002, D.H. Kavanaugh, P.E. Marek, H.B. Liang & D.Z. Dong collectors [1 female; CAS]). Gongshan County: Cikai Township (Nu Jiang at Dashada, 27.73845°/98.67092°, 1430 m, 8-9 October 2002, D.H. Kavanaugh, P.E. Marek & H.B. Liang collectors [6 males and 13 females; CAS, IOZ]); Dulongjiang Township (Bapo, Mulangdang, 27.75256°/98.34745°, 1355 m, 4 November 2004, H.B. Liang collector [3 males and 11 females; CAS, IOZ]), (south edge of Dizhengdang village along Silalong He, 28.07654°/98.32603°, 1890 m, 30 October 2004, D.H. Kavanaugh, G. Tang & D.Z. Dong collectors [2 males and 3 females; CAS, IOZ]), (Kongdang, 27.89791°/98.33843°, 1581 m, 30 May 2021, H.B Liang & Y. Xu Y. collectors [8 males, 5 females, IOZ]), (Pukawang, on road / 27.84016°/98.32233, 1458 m, 2021.5.29 N, H.B Liang & Y. Xu collectors [1 female, IOZ]). Tengchong County: Wuhe Township (Longchuan Jiang just below bridge at Menglian village, 24.89176°/98.67551°, 1230 m, 3 June 2006, D.H. Kavanaugh, R. L. Brett, H.B. Liang & D.Z. Dong collectors [30 males and 35 females; CAS, IOZ]), (Longchuan Jiang at Longjiang Bridge, 24.89889°/98.66667°, 1215 m, 28 October 2003, H.B. Liang & X.C. Shi collectors [1 male and 2 females; CAS, IOZ].
Members of this species were collected from the northern to the southern parts of the study area (Core Areas 1, 2, 3 and 6), on both sides of mountain range in the north, only on the eastern side in the central part (Core Area 3) and only on the western side in the southern part (Core Area 6). This distribution pattern is most likely an artifact of inadequate sampling on the western slope of the mountain range, much of which is in Myanmar, and in the small southeastern part of the study area.
Overall geographical distribution. (Fig. 23). This species has been known previously only from a few localities on the southern slope of the Himalaya in northcentral India (Uttarakhand). Records of its occurrence in the study area represent the first for China and the easternmost limit of its known distribution. Other new records from China are within Tibet (Medog County: Ximohe bridge, 29.3519 / 95.3417 °, 707 m, 25 August 2015, H.B. Liang collector [5 males, 5 females, IOZ]; Zha-Mo road Km 62, light trap, 29.7086°/95.5775°, 2787 m, 30 August 2015, H.B. Liang collector [1 male, IOZ]. Zayu County: Xia Zayu, 28.50760°/97.00965°, 1651 m, 4 July 2011, Y. Liu collector [9 males, 4 females, IOZ]). It is likely that T. elegans occurs also in suitable habitats in the intervening region, including northern Myanmar (Kachin State), northeasternmost India, Bhutan, and Nepal, at elevations between 400 and 2000 m along rivers draining the southern slopes of the Himalayan ranges in these areas.
Geographical relationships with other Tetragonoderus species. In the study area, members of this species have been found synotopic with those of T. parviculus and T. punctatus. The distributional range also overlaps that of T. arcuatus in the study area, but the two species have not yet been found syntopic. As noted above for T. arcuatus, the range of T. elegans broadly overlaps that of T. microthorax, but the latter species has not yet been recorded from the study area. Tetragonoderus elegans is also likely sympatric with T. arcuatus, T. microthorax, T. punctatus, and Tetragonoderus taeniatus (Wiedemann, 1823), in suitable habitats in at least some localities along the southern slope of the Himalaya between Uttarakhan and western Yunnan.
description: Published as part of Kavanaugh, David H., Cueva-Dabkoski, Mollie & Liang, Hongbin, 2023, Inventory of the Carabid Beetle Fauna of the Gaoligong Mountains, western Yunnan Province, China: Species of the Tribe Cyclosomini Laporte, 1934 (Coleoptera: Carabidae), with Descriptions of Two New Species., pp. 451-491 in Proceedings of the California Academy of Sciences 67 (20) on pages 466-468, DOI: 10.5281/zenodo.11067293