Mecyclothorax reidi, Baehr & Reid, 2017

Baehr, Martin & Reid, Chris A. M., 2017, On a Collection of Carabidae from Timor Leste, with Descriptions of Nine New Species (Insecta: Coleoptera, Carabidae), Records of the Australian Museum 69 (6), pp. 421-450 : 425-427

Mecyclothorax reidi sp. nov. Baehr

Figs 2 , 12

Holotype ♂, “ TIMOR LESTE Ramelau 8°54'28"S 125°30'10"E stunted eucs/vaccinium gully 2300–2400m 28.v.2012 C.Reid TL2012/092/577 grass tufts” K402541 ( AMS) . Paratypes (4): 2♂♂, 1♀, “ TIMOR LESTE Ramelau 8°54'45"S 125°29'58"E stunted eucs/vaccinium/open grass 2450–2550m 28.v.2012 C.Reid TL2012/091/576” K402540, K402542 (1♂, 1♀ AMS); K402544 (1♂ CBM) ; 1♀, “ TIMOR LESTE Hatubuilico Rd 11.5km W t’off h’way 8°53'12"S 125°32'49"E E urophylla /Vacc pasture/ gully 2050m 28.v.2012 C.Reid TL2012/080/762” K402555 ( AMS) .

Etymology. The name, proposed by MB, acknowledges coauthor and collaborator Dr Chris Reid, who collected this material.

Diagnosis. Small, unicolourous dark species with short, ovalshaped elytra and wide, cordiform, near base slightly excised pronotum. Elytra with four setiferous punctures. Aedeagus with compressed, not securiform apex. From M. timorensis distinguished by the larger number of elytral setae and the shape of the apex of the aedeagus.

Description. Measurements. Length: 4.4–4.7 mm; width: 1.20–1.33 mm; ratios: width/length of pronotum: 1.21–1.28; width base/apex of pronotum: 1.0–1.04; width pronotum/ head: 1.43–1.48; length/width of elytra: 1.40–1.45; width elytra/pronotum: 1.46–1.53.

Colour ( Fig. 2 ). Unicolourous very dark piceous to black, the lateral margin of the elytra barely paler. Labrum and mandibles reddish-brown, palpi yellow, 1st–3rd antennomeres and legs pale red, rest of antenna darker, more or less dark piceous. Lower surface more or less piceous, elytral epipleurae pale reddish.

Head ( Fig. 2 ). Rather narrow in relation to prothorax. Eye moderately large, slightly convex, laterad little protruded, orbit fairly large, oblique-convex, c. 1/3 of length of eye. Frontal furrows deep, elongate, oblique, attaining about the middle of the eye, laterally bordered by a narrow ridge. Parafrontal sulcus almost encircling the eye. Frons convex, usually without a median pit. Clypeal suture well impressed. Labrum transverse, truncate, 6-setose. Mandibles moderately elongate, apically suddenly curved. Mentum with distinct, apically rounded tooth. Submentum with very elongate setae. Posterior supraorbital seta situated about at posterior margin of eye bur slightly removed mediad. Antenna short, just surpassing the basal angle of the pronotum, median antennomeres slightly longer than wide. Surface impunctate, with faint, irregular transverse strioles, with very faint, superficial, about isodimetric microreticulation, glossY.

Pronotum ( Fig. 2 ). Moderately large, fairly wide but somewhat variable, considerably wider than long, disk fairly convex; lateral margin evenly convex, with a faint excision in front of the basal angle. Widest diameter slightly in front of middle. Base moderately wide, about as wide as the apex. Apex straight, apical angle slightly projected but rounded. Base slightly convex. Basal angle distinct, about rectangular. Marginal channel narrow, barely widened towards angle. Both, apex and base not margined.Anterior transverse sulcus shallow, little impressed, v-shaped, posterior transverse sulcus deep. Median line well impressed, anteriorly and posteriorly abbreviated. Basal groove short, irregularly circular, fairly deep. Basal area coarsely punctate-corrugate. Anterior marginal seta situated slightly in front of middle, in the marginal channel, posterior marginal seta situated at basal angle. Surface impunctate, on disk with only traces of extremelY superficial, slightlY transverse microreticulation, lateral parts and basal area more distinctly microreticulate, surface glossy.

Elytra ( Fig. 2 ). Moderately short and wide, dorsally convex, not widened apicad, widest diameter about at middle. Humerus obtusely rounded, lateral margin evenly convex. Basal margin distinct, oblique, slightly sinuate, connected to scutellary striole. Five or even six median striae well impressed and very coarsely punctate, slightly abbreviated at base, lateral striae less distinct; three median striae almost attaining the apex, the external striae increasingly abbreviated in front of apex. Five median intervals in basal half distinctly convex. Scutellary striole short, deep, situated mediad of the outturned sutural stria. Marginal channel narrow. 3rd interval with four setiferous punctures attached to the 3rd stria, the anterior puncture situated in basal third, the 2nd puncture about at middle, the 3rd puncture slightly behind middle, and the 4th puncture near the posterior third of the elytra. Punctures distinct, setae extremely short. Near apex with a single setiferous puncture at the end of the 3rd stria. Marginal punctures moderately conspicuous, 15–16 in a row that is slightly interrupted in middle, marginal setae elongate if not broken. Intervals impunctate, with faint, more or less superficial microreticulation consisting of transverse meshes. Surface fairly glossy, not iridescent. Metathoracic wings absent.

Lower surface. Largely impunctate. Metepisternum slightly longer than wide. Sternum VII in male bisetose, in female quadrisetose.

Legs. Without striking features. Three basal tarsomeres of male anterior tarsus expanded and biseriately squamose.

Male genitalia ( Fig. 12). In shape and structure quite similar to those of M. timorensis Genital ring slightly wider, asymmetric, with narrow base and wide, oblique apex. Aedeagus of same size and general shape, but apex on upper surface only obtusely raised, and the denticle at apex of orificum extremelY small or even absent. Orificium and internal sac quite similar. Left paramere slightly shorter and more compact, bisetose at apex , without setae at lower margin. Right paramere also considerably more compact, with a not sclerotized narrow rim along upper border, bisetose at apex and with about 11–12 elongate setae at lower margin.

Female gonocoxites. Similar to those of M. timorensis sp. nov.

Variation. Little variation noted.

Distribution. Western part of Timor Leste, on the highest mountain in Timor (Ramelau) and associated ridges.

Collecting circumstances. Collected on the ground in open eucalypt woodland with grass and Vaccinium , between 2050 and 2550 m altitude.

Remarks. The two new species described in the present paper are the first records of the genus Mecyclothorax from the island of Timor. TheY partlY fill the distribution gap of the genus between northern Australia and New Guinea in the south-east, and Java and Borneo in the north-west.

Apparently both species are closely related, because body shape, structure of the surface, and shape and structure of the aedeagus are verY similar. TheY differ onlY in the number of tactile elytral setae and in the shape of the apex of the aedeagus. According to the shape of the aedeagus, particularly of the apex, both species seem to belong to the ambiguus -group of species which is widely distributed in southern and eastern Australia and in New Zealand. The aedeagus of M. timorensis is particularly similar to that of M. rotundicollis (White, 1846) from New Zealand. However, body shape, size of the antenna, and surface structure of both species from Timor differ from those of the ambiguus -lineage.

Apparently, the species from Timor do not have closely related species in New Guinea, as far as the mecyclothoracine fauna of this island is known, whereas the Oriental species, particularly those from Java, have not been studied recently, so that the structure of their male genitalia is not known in detail. Therefore, the relationships of the species from Timor to species from Java are uncertain.

Because the genus Mecyclothorax certainly has originated in Australia, where, in terms of their phylogenetic status, the apparently most plesiotypic species occur, even the few Oriental species are an Australian faunal element.

Thus far, the species are only known from a restricted area in the western part of Timor Leste where they have been sampled in montane areas above 1800 m. At some localities both species have been collected together. Sampling records suggest that both species are ground living and occur in open eucalypt woodland with Vaccinium , grass, and moss, where they have been mostly collected from tufts of grass or in pitfall traps. This is also the plesiotypic habitat in Hawaii ( Liebherr, 2015).

Figures

Figure 2. Mecyclothorax reidi sp. nov. (body length 4.7 mm).