Mecyclothorax jameswalkeri, Liebherr, James K., 2018

Liebherr, James K., 2018, Taxonomic review of Australian Mecyclothorax Sharp (Coleoptera, Carabidae, Moriomorphini) with special emphasis on the M. lophoides (Chaudoir) species complex, Deutsche Entomologische Zeitschrift 65 (2), pp. 177-224 : 177

Mecyclothorax jameswalkeri sp. n. Figures 4B, 11C

Diagnosis

(n = 1). This, the second of two Australian species of subgenus Eucyclothorax - with M. darlingtoni -characterized by the absence of basal pronotal setae, can be diagnosed by aspects of the narrow body, including: 1, a narrow, basally constricted pronotum, MPW/PL = 1.28, MPW/BPW = 1.88; and 2, narrow, subparallel elytra, MEW/EL = 0.64. Like M. darlingtoni , the prosternum of this species has a punctate medial depression anterad the prosternal process, in this instance lined with 7 punctures. The prosternal anteapical groove is continuous and distinctly punctate laterally, more irregular and smoother ventrally. The eyes are large and moderately convex, and they cover much of the ocular lobe; EyL/OLL = 0.95. The parascutellar striole is composed of 7-8 deep, isolated pits. Standardized body length 4.9 mm. Setal formula ++/+‒/+2++.

Description.

Head elongate with large eyes (Fig. 4B), vertex broadly convex between deep, sinuously convergent frontal grooves that continue anterolaterally onto clypeus, anterior supraorbital seta in deep depression behind frontolateral callous; labrum broadly, slightly emarginate; mandibles elongate, overall length 1.9 × distance from anterior condyle to lateroapical labral margin; mentum tooth with obtuse side, apex shallowly bifid; mentum breadth/length across lateral lobes = 2.57. Pronotum with lateral setal articulatory socket within associated expansion of lateral marginal depression, the lateral marginal depression otherwise broad enough to observe microsculpture at its deepest part, its margin beaded; hind angle obtusely rounded, the lateral margin slightly sinuate before angle; medial base unmargined inside marginal bead that extends only slightly inside hind angle, convex, with ~10 small punctures each side from midline to laterobasal depression; laterobasal depression a narrow oblique groove extended from mesad sinuate lateral margin toward middle of disc; median longitudinal impression very fine and shallow, occluded by broad, shallow transverse wrinkles, deepest between arms of anterior transverse impression; anterior transverse impression smooth, continuous from near midline to rounded, slightly protruded front angles; marginal bead of procoxal cavity lined anteriorly with 3 small isolated punctures: proepisternum impunctate. Mesepisternum punctate at its deepest portion, about 9 deep punctures in 2-3 dorsoventral rows. Elytra with serially punctate striae 1-6, stria 7 absent except near subapical seta; elytral punctures round with distinct center point, separated by their diameter on disc, smaller in stria 6 where separated by 2 punctural diameters; sutural stria distinctly punctate basally, becoming smoother toward apical 1/4 of length, but sutural interval slightly convex (teneral condition?), the transition from punctate to smooth as in Fig. 12A; stria 8 deep, punctate and bordering lateral marginal depression anteriorly, deeper, smooth and distinct mesad posterior series of lateral elytral setae; lateral elytral setae arrayed as 7 + 6 (anterior series setae and posterior series setae); subapical sinuation evident, abruptly curved anteriorly, but elytral plica covered by margin in dorsal view. Metepisternum moderately elongate, maximum width/lateral length = 0.44; metasternal process acute, apex knob-like, margins upraised, twice at broad at apex; metathoracic flight wing macropterous, veins evident in folded condition under teneral elytra, apex reflexed. Abdomen with linear wrinkles laterally on visible ventrites 1-3, shallow rounded depressions laterally on ventrites 3-6; suture between ventrites 1 and 2 slightly sinuate, deep midway along suture; female with 2 marginal setae each side of apical ventrite plus a trapezoidal patch of 4 smaller medial setae. Microsculpture of frons indistinct, surface glossy, vertex with indistinct transverse mesh in parts; pronotal disc and median base with shallow transverse mesh, sculpticell breadth 3 –4× length, sculpticells irregularly swirling in laterobasal depressions; elytral disc with transverse lines loosely connected into mesh, the surface subiridescent; elytral apex with transverse lines in a loose mesh, the convex, estriate surface iridescent. Coloration (assessed on single teneral specimen) of vertex rufous with brunneous cast; antennomeres 1-3 rufoflavous, 4-11 with piceous cast; pronotal disc dark rufous, margins paler, flavobrunneous; elytral disc rufobrunneous, sutural interval concolorous, lateral marginal depression rufoflavous, translucent; elytral apex broadly flavobrunneous; proepipleuron rufoflavous, proepisternum rufobrunneous; abdomen rufobrunneous, apical half of apical visible ventrite paler, rufoflavous; femora and tibiae flavous with brunneous cast.

Female reproductive tract (n = 1). The single teneral female specimen of this species was not dissected.

Holotype.

Holotype female (BMNH): Albany / W. Australia / J.J. Walker // G. C. Champion Coll. / B. M. 1927-09 // HOLOTYPE / Mecyclothorax / jameswalkeri / J.K. Liebherr 2018 [black-bordered red label].

Etymology.

This species commemorates James John Walker, Commander and Fleet Engineer, Royal Navy, active member and officer in many scientific societies–including President of the Linnean Society of New South Wales ( Walker 1921)-and in retirement, an editor of the Entomologistʼs Monthly Magazine ( Poulton 1939). Walkerʼs collections from Australia and New Zealand were passed to George C. Champion, his brother-in-law, and then bequeathed by Champion to The Natural History Museum, London. Walkerʼs collections were as far flung as the British Empire, with his naval duties taking him to places where he could collect. Among many other species, carabid beetles named after him include: Protopaussus walkeri Waterhouse (1897) from China; Calosoma walkeri Waterhouse (1898), junior synonym of C. oceanicum Perroud, from Australia; Rhaebolestes walkeri Sloane (1903) from New South Wales; Duvaliomimus walkeri ( Broun 1903), Megadromus walkeri (Broun, 1903), and Mecodema walkeri Broun (1903), the last a junior synonym of Mecodema howitti ( Castelnau 1867), all from South Island, New Zealand; and Trirammatus walkeri ( Andrewes 1931) from Juan Fernandez Island. Walkerʼs collecting acumen can be attested to by his discovery of this broad assortment of carabid diversity.

Distribution and habitat.

The lone specimen of this species is from Albany, W.A. (Fig. 11C). We know nothing specific about the habitat in which this beetle was discovered. The specimen is macropterous with the wings bearing well-developed venation and a reflexed apex, the wing structures being visible through the very translucent elytra of the teneral specimen. Thus occupation of a riparian habitat requiring recolonization of habitat patches may be predicted ( Darlington 1936, 1943).