Tetragonoderus punctatus
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 punctatus

description: Tetragonoderus punctatus (Wiedemann)
Figures 12, 13E, 14E, 15E, 16E, 17E, 19 C-D, 21, and 23.
Bembidium punctatum Wiedemann, 1823:61. LECTOTYPE, here designated, a male, in ZMUC, labeled: “TYPE” [red label]/ “Bengala Westermann Punctatus Wied. ” [handwritten]/ “ZMUC 00027869”/ “ LECTOTYPE Bembidium punctatum Wiedemann, 1823 design. by D.H. Kavanaugh & M. Cueva-Dabkoski 2022” [red label]. Paralectotypes examined: 1 female, in ZMUC, labeled: “Mus. Westerm.”/ “TYPE” [red label]/ “Bengal Maj. 1808. Punctatus Wied. ” [handwritten]/ “ZMUC 00027868” [label upside down]/ “ PARALECTOTYPE Bembidium punctatum Wiedemann, 1823 design. by D.H. Kavanaugh & M. Cueva-Dabkoski 2022” [yellow label]. Type locality: “Bengalia” [area which now includes West Bengal (eastern India) and Bangladesh].
Tetragonoderus punctatus (Wiedemann), Dejean (1829:505); Schmidt-Göbel (1846:92); Chaudoir (1876:48); Andrewes (1921:174); Csiki (1932:1298); Lorenz (2005:453).
Diagnosis. Adults of T. punctatus 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 = 4.5 to 4.8 mm, females = 4.6 to 5.4 mm; pronotum piceous or rufopiceous, with or without faint greenish metallic reflection; elytral color pattern as in Fig. 12A, with dark areas less expansive, connection between medial portion of the basal dark band and humeral portion absent or very narrow, less than one-fifth the length of humeral portion, middle discal band with portion between anterior and posterior dark edges not or only slightly darker than remainder of pale elytral areas; femora pale tan; pronotum (Fig. 13E) widest near mid-length and posterior to insertion of midlateral seta, not or only very slightly narrowed basally (ratio PWB/PWA = 1.15 to 1.25), lateral margins slightly and evenly convex or straight or very slightly sinuate anterior to basal angles; elytra slightly to distinctly truncate apically; front tarsomeres 1 to 3 without lateral expansions (Figs. 14E, 15E); male with middle mesotarsomeres (Fig. 16E) only slightly wider than in female and with only tarsomeres 1 to 3 with pads of adhesive setae ventrally (i.e., tarsomere 4 without adhesive setae ventrally) (Fig. 17E); median lobe of male genitalia (Figs. 19C,D) with apical lamella short and broad, internal sac without spines.
In the study area, specimens of T. punctatus (Fig. 12A) might be confused with those of T. elegans (Fig. 10A) and also with those of T. microthorax (Figs. 13F, 14F, 15F, 16F, 17F, 19 E-F, and 20), although the latter has not yet been recorded from the Gaoligong Shan region. Tetragonoderus punctatus members differ from those of T. elegans in having the forebody slightly lighter in color (i.e., less heavily pigmented) and the elytral pattern of dark areas less extensive, with connection between medial portion of the basal dark band and humeral portion absent or very narrow, less than one-fifth the length of the humeral portion (at least one-fourth the length of the humeral portion in T. elegans), the middle discal band with the area between anterior and posterior dark edges not or only very slightly darker than remainder of pale elytral areas (distinctly darker tan-orange in T. elegans), and with a less distinct and discontinuous preapical dark band. Also the pronotum is proportionally slightly wider (ratio PWM/EW = 0.55 to 0.57; in T. elegans = 0.51 to 0.55), widest at or near midlength, posterior to the insertion of the midlateral seta (widest more anteriad and at or near the insertion of the midlateral seta in T. elegans), less distinctly narrowed basally (ratio PWM/PWB = 1.06 to 1.13; in T. elegans = 1.13 to 1.20), and the lateral margins are not at all or only very slightly sinuate anterior to the basal angles (distinctly sinuate in T. elegans). Males differ in several additional features. In T. punctatus males, the middle tarsi are only slightly wider than those in females and middle tarsomere 4 lacks a pad of adhesive setae ventrally (Figs. 16E, 17E), whereas middle tarsomeres 1 to 4 are distinctly wider than in females and bear adhesive setae ventrally in T. elegans males (Figs. 16C, 17C). Males also differ in the form of their genitalia, with the median lobe (Figs. 19C,D) slightly shorter and distinctly thicker, the apical lamella shorter and broader, and the internal sac without distinct spines in T. punctatus. In contrast, the median lobe of T. elegans males (Figs. 19A,B) is longer and more slender, the apical lamella is much longer, narrower, and distinctly curved ventrad, and the internal sac is armed with five or more large and distinct spines.
Members of T. punctatus are extremely similar to those of T. microthorax and these two species are no doubt confused in collections. Most specimens of T. punctatus are slightly larger (BL males = 4.5 to 4.8 mm, females = 4.6 to 5.4 mm) than those of T. microthorax (BL males = 3.9 to 4.6 mm, females = 4.2 to 4.7 mm). They have the pronotum (Fig. 13E) slightly shorter and wider (ratio PWM/PL = 1.52 to 1.70), widest at or near midlength and posterior to insertion of midlateral seta and not or only very slightly narrowed basally (ratio PWB/PWA = 1.15 to 1.25), and with the lateral margins slightly and evenly convex or straight or very slightly sinuate anterior to the basal angles. In T. microthorax, the pronotum (Fig. 13F) is slightly longer and narrower (ratio PWM/PL = 1.48 to 1.57), widest anterior to mid-length at or near insertion of midlateral seta, slightly to moderately narrowed basally (ratio PWB/PWA = 1.04 to 1.14), and with the lateral margins slightly to moderately sinuate anterior to the basal angles. Unfortunately, the ranges in size and pronotal proportions (except for ratio PWB/PWA) seen among specimens of these two species overlap slightly, so measurements alone cannot distinguish all specimens of the two. The male genitalia are also very similar, except that the apical lamella of the median lobe is slightly shorter and broader in T. punctatus males (Figs. 19C,D) than in T. microthorax (Figs. E,F) males. There are also subtle differences in the convexity of the elytral intervals (flat in T. punctatus and slightly convex in T. microthorax) and depth of impression of the striae (moderately deep in T. punctatus, even deeper in T. microthorax).
Habitat distribution. Members of this species were found at night, running on the surface of the open sandy shores of the Longchuan River (Fig. 21), a medium-sized stream, at two sites (at elevations of 1215 and 1230 m, respectively). They were running on the same beaches with adults of T. elegans, which were much more abundant. They appear to prefer upper beach areas, where zones of slightly moist and dry sand meet.
Geographical distribution within the Gaoligong Shan. Fig. 12B. We examined a total of five specimens (one male and four females) from the following localities: 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 [one male and three 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 female; CAS].
At present, this species has been recorded only from the southwestern part of the study area (Core Area 6).
Overall geographical distribution. Fig. 23. We have examined specimens of this species only from “Bengala” (i.e., West Bengal (India) and/or Bangladesh) and the localities in the Gaoligong Shan as listed above. Its occurrence in the study area represents the eastern limit of its known geographical range and also a first record for China. It is likely that this species occurs also in northern Myanmar and northeastern India along rivers draining the western slope of the Gaoligong Shan and the southern slope of the eastern part of the Himalaya Mountains, respectively, at low elevations (1000 to 1300 m).
Geographical relationships with other Tetragonoderus species. Members of this species have been found synotopic with those of T. elegans and T. parviculus in the study area. The range of this species also overlaps that of T. arcuatus in the study area, but these two species have not yet been found syntopic. Also, the range of T. microthorax broadly overlaps that of T. punctatus, but the former species has not yet been recorded from the study area. We note that all current records of T. microthorax are from localities well below 1000 m in elevation and such elevations are absent from all but the extreme southwesternmost part of the study area, which we were unable to sample.
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 472-474, DOI: 10.5281/zenodo.11067293