Mochtherus tetraspilotus (MacLeay)

Hunting, Wesley & Yang, Man-Miao, 2019, A taxonomic review of the pericaline ground-beetles in Taiwan, with descriptions of new species (Coleoptera, Carabidae, Lebiini), ZooKeys 816, pp. 1-164 : 134-138

Mochtherus tetraspilotus (MacLeay) Figs 100, 101 A–D, 102C, 103

Dromius tetraspilotus MacLeay, 1825: 25.

Thyreopterus tetrasemus Dejan, 1831: 448.

Mochtherus angulatus Schmidt-Goebel, 1846: 76; Schaum 1860:187; Redtenbacher 1868: 7; Andrewes 1933: 461.

Panagaeus retractus Walker, 1858: 203.

Cyrtopterus quadrinolatus Motschulsky, 1861: 106.

Mochtherus tetraspilotus MacLeay: Chaudoir, 1869; Bates 1886: 203; 1892: 412; Andrewes 1919: 163; 164, 189; Andrewes 1923: 45; Andrewes 1927: 12; Andrewes 1929: 313; Andrewes 1930; 336; Andrewes 1933: 2; Heller 1919: 273; Csiki 1932: 1382; Shibata 1962: 18; Jedlička 1963: 353; Kisrchenhofer 1994: 1048; Lorenz 2005: 460.

Types and other material examined.

62 specimens of M. tetraspilotus : 28 males and 34 females. For further details see EH Strickland Virtual Entomology Museum Database.

Type locality.

Java.

Diagnosis.

Specimens of this species are easily distinguished from other species of Mochtherus by the smaller size (less than 7.5 mm) and baso-medial half of elytra with setae and associated punctures not distinctively differing from remainder of disc.

Redescription.

OBL 6.17 - 7.00 mm. Length (n = ten males, ten females): head 0.72 - 0.76, pronotum 1.08 - 1.20, elytra 3.67 - 4.17, metepisternum 0.84 - 0.96 mm; width: head 1.36 - 1.52, pronotum 1.60 - 1.88, elytra 2.67 - 3.17, metepisternum 0.52 - 0.56 mm.

Body proportions. HW/HL 1.89 - 2.11; PWM/PL 1.41 - 1.63; EL/EW 1.25 - 1.44; ML/MW 1.40 - 171 mm.

Color. Fig. 100. Dorsum of head rufo-brunneous to piceous, clypeus rufo-brunneous to brunneo-piceous, lighter than head, labrum brunneous, brunneo-piceous to piceous centrally; palpi and antennae brunneo-testaceous to brunneous; pronotum brunneous to brunneo-piceous, margins somewhat lighter; elytral disc brunneo-piceous to piceous, suture and margins brunneous to brunneo-piceous, somewhat lighter than disc, with four testaceous to rufo-testaceous maculae, two anterior and two posterior, anterior macula ovoid, from stria 4 (sometimes diffusely into interval 4) to interval 8, nearest to base at interval 7, closest to apex in interval 5 or 6, posterior macula circular to ovoid, from stria 1 to stria 5 (sometimes stria 4), closest to base in interval 4, nearest to apex in interval 3-4; ventral surface of head, pronotum and thoracic sclerites brunneous, abdominal sclerites testaceous to brunneo-testaceous; legs testaceous to brunneous.

Microsculpture. Dorsum of head with mesh pattern somewhat granulated, isodiametric, labrum with sculpticells shallow, stretched longitudinally; pronotum with microsculpture transverse; elytra with sculpticells slightly wider than long, almost isodia metric; metepisternum with microsculpture almost isodiametric to isodiametric; other ventral surfaces with microsculpture transverse.

Macrosculpture and pilosity. Dorsum of head faintly and longitudinally rugulose, with scattered setigerous punctures, setae short and fine, clypeus rugulose, with several scattered setigerous punctures, labrum relatively smooth, with several short setae in apical half; scrobe of mandible setose at base; pronotum faintly rugulose transversely, punctate and densely setose; elytra with intervals punctate and setose, setae longer and more dense medially in basal half, striae faintly punctate, setae hardly visible at 50 ×; ventral surface with randomly scattered setigerous punctures, setae relatively dense and easily visible in lateral view.

Fixed setae. Elytra with two setae in interval 2, one seta just back from mid-length, one seta in apical 1/6.

Luster. Dorsal surface moderately dull; ventral thoracic sterna and abdominal sterna moderately glossy.

Head. Mandibles with wide base, short, mostly concealed by labrum in resting position; labrum longer than wide, rectangular; mentum with shallow tooth; eyes convex.

Pronotum. Anterior transverse impression very shallow; posterior transverse impression moderately deep; median longitudinal impression moderately deep; Disc convex, apical edge slightly emarginate, basal angles obtuse; lateral margins broadly rounded in apical portion, markedly sinuate from lateral seta to base.

Elytra. Lateral margin smooth, parallel along length.

Legs. Tarsal claws pectinate, three to four denticles per claw, apical denticles rather long.

Male genitalia. Fig. 101 A–D. Length 0.84 - 0.92 mm. Phallus uniform width along length, apex bluntly rounded and somewhat triangular in ventral view, more constricted and pointed in lateral view; endophallus relatively short, one basal microtrichial field (mtf), microtrichia distinctively long, two distinctive endophallic lobes (el), one near base and one medially.

Female genitalia. Fig. 102C. Width 0.84 - 0.88 mm. Two lateral ensiform setae (les), rather long. One spermatheca (sp1), cylindrical, elongate and narrowing towards apex with markedly elongate apical end; ring sclerite (srs) separating spermatheca duct from spermatheca; one spermathecal accessory gland (sg), spermathecal gland duct (sgd) attachment site on right side of ring sclerite when viewed from ventral aspect.

Habitat, habits, and seasonal occurrence.

The known elevational range of M. tetraspilotus in Taiwan is from 480 to 1300 meters. Only one specimen is known from over 725 meters. Adults are crepuscular or nocturnal and are found in mixed primary and secondary forest of montane areas, as well as disturbed areas. The vast majority of known specimens (54) were collected within a week of each other in 2013 on two nights in late November and early December. They were collected from the underside of fallen trees and deadwood. A single specimen is known from July and another from September. Known methods of collecting this species are sweep netting and hand collecting.

Geographical distribution.

Mochtherus tetraspilotus is widespread and known from Japan, Burma, Philippines, Laos, Borneo, Java, Ceylon, India, USA, and Taiwan. For additional Taiwan collecting localities, see Figure 103.