Trirammatus torqueotrochantus, Will, 2004

Will, Kipling W., 2004, A remarkable new species of Trirammatus Chaudoir (Coleoptera: Carabidae: Pterostichini) from the Valdivian Forest of Chile, Zootaxa 758, pp. 1-9 : 4-6

Trirammatus torqueotrochantus NEW SPECIES

Holotype. Male­ verbatim label data: “Caramavida Arauco Prov. XII­25/31 ­53 CHILE Pena” [approximate coordinates 37°41' 00" S / 073° 21' 00" W]

Paratypes. 1 male, same data as holotype. 1 Male and 1 Female­ verbatim label data “Alto Caicupil AraucoProvI­7­54 1200/1300 M., CHILE Pena” [approximate coordinates 37° 51' 00" S 073° 16' 00" W]. All specimens deposited Museum Comparative Zoology, Harvard ( MCZ).

DESCRIPTION. Small sized, overall length of type 8.5 mm, range of series 7–8.5 mm. Dorsal surface deep brunneous with a distinct aeneous luster. Ventral body surface, base of legs up to middle of femora, and tibiae brunneous; mouthparts and antennae paler rufobrunneous; middle of femura pale nearly flavous.

Head.— Two supraorbital setae. Ocular ratio (width over eyes/ width between eyes at level of anterior supraorbital setae) of type 1.16, range of series 1.16–1.37. Mentum tooth broad and blunt at apex. Epilobes of mentum divergent; mentum transverse form. Suture between mentum and submentum distinct and entire. Submentum tumescent. Glossal sclerite with two apical setae. Paraglossae glabrous. Maxillary and labial palpi fusiform. Penultimate labial palpi with two prominent setae. Microsculpture of head effaced on disc, except for scattered micro­punctulae. Frontal impressions deeply impressed, well defined, divergent to anterior supraorbital setae. Clypeus with large setae at each apicolateral corner, slightly emarginate along anterior edge.

Thorax.— Pronotal form quadrate ( Fig. 1 ); two pair lateral setae; lateral margin with narrow bead; margins slightly sinuate and nearly straight to the hind angles, which are slightly obtuse; basal margin medially emarginate; front angles slightly produced; basal margin not bordered; basal foveae broad shallow, distinctly punctulate. Microsculpture on disc nearly effaced and surface relatively shiny. Microsculpture of elytra with slightly more evident microlines forming mesh; surface shiny; basal section of stria 1 absent; parascutellar striae present; intervals nearly equal width on disc, intervals flat except laterally and apically on elytra where they are slightly convex; striae very shallow especially on elytral disc and laterally in middle third; elytral humeral tooth very large, positioned anterad interval 8. Elytra with notable depressed regions laterally in basal third of length. Metathoracic flight wings completely reduced. Legs ( Fig. 2 ). Procoxae globose and glabrous. Protrochanters with one setae. Profemora robust, ventral surface in male type with prominent posterioventral denticle ( Fig. 2 B); female paratype more slightly built, without denticle; one posterioventral and one posterioapical setae. Protibiae slightly expanded at apex, few small spinose setae laterally in male type and other males, setae notably larger and heavier built in female paratype. Three protarsi expanded and ventrally with pad of articulo­setae ( Stork 1980) in male; female paratype with small compact protarsi. Mesocoxae globose with two setae, one lateral, one medial. Mesotrochanters with one seta.

Mesofemora robust nearly rectangular in form with two setea on anterior face, four­five setae on dorsal face. Mesotibiae in male type arcuate, with lateral row of heavy setae and denser brush of fine setae medially; female paratype with mesotibiae nearly straight and same setal pattern as male; mesotibial apex with prominent spine; apical ctenidium well developed. Mesotarsi small and compact. Metacoxae with two setae; margin pointed posteriorly; metacoxal sulcus straight and appressed to anterior margin. Metatrochanter in male exceptionally elongate, apex extending to apex of femora; apex slightly twisted, pointed falcate; in female paratype metatrochanter moderately elongate, extending to middle of femora, rounded at apex. Metafemora robust with two setae on anterior face. Metatibiae somewhat arcuate in male type, straight in female paratype; setal pattern as in mesotibiae. Metatarsi slightly more elongate than mesotarsi, dorsally smooth.

Abdomen.— Shallowly and very irregularly depressed laterally on sterna V–VII; in some specimens nearly forming rudimentary sulci. Sterna V–VI with medial pair of setae, VII with two setae in male and four in female. Male median lobe of aedeagus simple, straight, evenly rounded at apex; ostium large, covering most of the dorsal surface; endophallus evenly covered with minute spinules, without large spines. Female reproductive tract typical for euhcroine taxa, bursa bent to left, spermatheca large with appended gland and gland duct diverticulum.

GENERIC PLACEMENT. Although the overall phylogeny of South American pterostichines is still not settled, T. torqueotrochantus does share the presumed synapomorphic female reproductive tract form with other euchroines and shares the characteristic two setae at the base of each tarsal claw, known within pterostichines only in Trirammatus species. Outside of the obvious modifications of the trochanters and elytra, T. torqueotrochantus appears to be quite similar to other Trirammatus species and so is placed in this genus.

HABITAT. The specimen label data suggest that this species was likely collected in araucarian and deciduous forest, i.e., “bosque caducifolio” and within an altitude range of 100­ 500 m.

IDENTIFICATION. This species will trace through Straneo’s key to genera (Straneo 1979,350) to couplet 38. This couplet distinguishes between Parhypates s. lat. Motschulsky and Trirammatus s. lat. based on the relative length of the metepisternum. The shortening of the metepisternum is tied to flight­wing loss throughout carabids and T. torqueotrochantus is a flightless species, unlike the other taxa described in Trirammatus . Additional and adjusted couplets can be inserted to accommodate flightless Trirammatus species with short metepisterna and other genera considered herein. The second half of couplet 44 is missing in Straneo’s key and is altered here. Couplet 45 can be eliminated.

38(37) Metepisternum short, anterior and lateral margins subequal........................... 38a 38' Metepisternum elongate, lateral margin longer than width at anterior margin .... .............................................. Trirammatus Chaudoir (sensu latiore, in part)...43 38a (38) One setae at the base of the tarsal claws ............................................................... ................................................................ Parhypates (sensu latiore) Motschulsky 38a’ Two setae at the base of the tarsal claws .............................................................. ....................................................... Trirammatus (sensu stricto, in part) Chaudoir 43 (38´) Elytron with parascutellar stria joined to stria one and angular base of stria one absent; two setae at the base of tarsal claw ........................ Trirammatus (in part) 43´Elytron with both parascutellar stria and angular base of stria one impressed; stria one continuous with angular base of stria and/or parascutellar stria; one setae at the base of tarsal claw........................................................................... 44 44 (43´) Stria one continuous with angular base of stria one and separate from parascutellar stria ........................................................................................... Pachymorphus 44' Prosternal process with apex margined ............................................. Plagioplatys

Figures

FIGURE 1. Dorsal habitus of Trirammatus torqueotrochantus new species. Male holotype.

FIGURE 2. Anterior face of legs of Trirammatus torqueotrochantus new species. A, C and E = Female pro, meso and meta legs respectively. B, D and E = Male pro, meso and meta legs respectively.