Mecyclothorax flavipes, Liebherr, 2009

Liebherr, James K., 2009, Native And Alien Carabidae (Coleoptera) Share Lanai, An Ecologically Devastated Island, The Coleopterists Bulletin 63 (4), pp. 383-411 : 389-391

Mecyclothorax flavipes , new species

( Figs. 2A , 3A–B , 4A–B , 5A )

Diagnosis. Beetles with glossy, rufopiceous head, pronotum and elytra, contrasted with the flavous antennae and legs. The glabrous pronotum is convex with very narrow lateral margins that are only slightly paler in color than the disc, the basolateral margins briefly sinuate anterad the bluntly angulate, obtuse hind angles ( Fig. 2A ). The anterior supraorbital seta is absent, and the posterior seta is situated just laterad the dorsal terminus of the postocular groove. This species is most similar in body shape to M. simiolus (Blackburn) of Oahu, however, beetles of this species are larger—standardized body length 4.9–5.2 mm versus 4.0– 4.6 mm for M. simiolus —and the eyes are more convex in this species than in M. simiolus , with an ocular ratio 1.50–1.54 versus 1.40–1.43 in the latter. Moreover, M. simiolus individuals have the second elytral stria absent from the elytral apex with that character aiding the species’ placement in the M. scaritoides species group (Liebherr 2009), whereas in M. flavipes individuals stria 2, though shallow, can be traced to the elytral apex.

Description. Vertex and frons slightly convex between the shallow, finely incised frontal grooves, clypeo-ocular region laterad grooves raised into elongate callus, frontal groove nearly meeting postocular groove; mentum tooth flattened apically, lateral margins divergent resulting in rhomboid shape. Pronotal disc convex; median base convex between very small and deep laterobasal depressions located just mesad bluntly angled hind angles, base with 15–20 small, isolated punctures each side of midline, basal margin with very narrow bead medially, the bead extended laterally to mesal margin of laterobasal depression; median longitudinal impression with several isolated punctures near median base, obsolete on disc; anterior transverse impression finely incised though shallow, smooth, deepest laterally at juncture with narrowly rounded, non-protruded front angles; lateral margin beaded, lateral marginal depression mesad bead obsolete; prosternal projection unmargined ventrally, posterior face slightly convex between procoxae. Elytra convex, suborbicular ( Fig. 2A ), the base somewhat extended laterally mesad humeral angle; striae 1–3 continuous and punctate on disc, stria 4 shallower though still punctate and continuous, stria 5 represented by a discontinuous series of punctures, striae 6 and 7 obsolete; stria 1 consisting of four isolated punctures laterad parascutellar striole that is also 4-punctate; elytral apex with sutural stria 1 deep and continuous, stria 2 very shallow though traceable, striae 3–6 obsolete, only stria 7 evident for short distance before apex; parascutellar seta present; two dorsal elytral setae present each side; lateral elytral setae configured as 7(6) + 6; no apical seta present near apex of stria 2. Fourth metatarsomere emarginate apically, the outer apical lobe 0.5 3 mediodorsal tarsomere length; tarsomeres relatively short, robust. Metepisternum appearing slightly elongate, though mesal margin length is only 1.1 3 length of anterior margin. Microsculpture of head an intermittent transverse mesh, interspersed with glossy portions of cuticle; pronotal disc glossy, microsculpture obsolete; elytra with shallow transverse-mesh microsculpture, sculpticell breadth 2–4 3 length; thoracic ventrites glossy, smooth, the metepisternum and metepimeron covered with isodiametric sculpticells; abdominal ventrites with transverse mesh microsculpture medially, an isodiametric mesh laterally.

Coloration. In addition to diagnosis, palpomeres flavous with diffuse smoky cast; elytral lateral marginal depression narrowly flavous anteriorly, flavous border expanded posteriorly to cover 7th and 8th intervals anterad subapical sinuation, somewhat broader at apex, sutural interval rufous; pro- and elytral epipleura rufoflavous, concolorous with lateral reaches of visible ventrites 3–5 and apical margin of ventrite 6, median portions of ventrites and abdominal sternites piceous; legs including trochanters flavous, coxae rufopiceous.

Male genitalia (n 5 1). Aedeagal median lobe robust, median dorsoventral breadth 0.25 3 distance from tip to distal margin of sagittal crest ( Fig. 3A ), median lobe ventral surface curved in apical half of length; lobe apex extended for short distance apicad ostial opening, the tip tightly rounded and apical face slightly convex; based on one uneverted specimen, the dorsal plate is elongate, its length 0.37 3 distance from basal lobe sagittal crest to median lobe apex, and the sac is covered with a well-developed field of microspicules.

Female reproductive tract (n 5 1). Female bursa copulatrix with accessory dorsal lobe attached to dorsal surface of a distinct ventral lobe ( Fig. 4A ), the dorsal lobe juncture distinctly apicad the junction of common oviduct and ventral lobe; spermathecal duct short, spermatheca just extended beyond lateral margin of bursa; spermathecal gland duct short, the duct about half length of spermathecal duct; basal gonocoxite 1 with apical fringe of three setae ( Fig. 4B ), and a small seta on mesal margin near medioapical angle (not considered homologous with apicomedial seta, see Fig. 4D ); apical gonocoxite 2 broad basally, with basolateral margin recurved anterad, lateral margin of apical gonocoxite strongly curved, apex tightly rounded; lateral ensiform setae of apical gonocoxite small, dorsal ensiform seta and two apical nematiform setae also present.

Types. Holotype male (BPBM), dissected and card mounted, genitalia in polyethylene genitalia vial on pin: HAWAIIAN IS: Lanai I. Monroe [sic Munro] Rd.; nr. Lanai-hale, 1,000 m, 10.i.1987 / on live Casuarina bark / G. Paulay and S. Montgomery, Coll. BISHOP MUSEUM Acc. # 1987.027 / Mecyclothorax n. sp. variipes male 1 det. J. Liebherr / HOLOTYPE Mecyclothorax flavipes det. J.K. Liebherr 2009 (black-margined red label). Paratypes. HI: Lanai, Munro Tr. near Lanaihale, 1,000 m el., on live Casuarina bark, 10-I-1987, Paulay and Montgomery (BPBM, 1), on dead Eucalyptus trunk, 10-I-1987, Paulay and Montgomery (BPBM, 1); Waiakeakua, 990 m el., on tree trunks and beating vegetation at night, 2-V-1993, Liebherr (CUIC, 1).

Etymology. The epithet flavipes signifies the distinctive yellow legs and tarsi of this species, and is to be treated as a noun in apposition.

Distribution. Recorded from the summit ridge of Lanai at Lanaihale and Waiakeakua ( Fig. 5A ), two localities near 1,000 m elevation and separated by 1.75 km.

Habitat. Three of the four specimens are recorded from the trunks of nonnative trees, either Casuarina or Eucalyptus , within the native cloud forest community ( Fig. 1 ). Thus it appears this species includes arboreal microhabitats within its ecological preferences, though whether that substrate comprises native or non-native plant species is of lesser importance. The 1993 specimen was collected during a nighttime stop, along with Blackburnia depressa (Sharp) , B. filipes (Sharp) , and M. filipes .

Figures

Fig. 2. Mecyclothorax spp. (vignettes represent actual body size). A. M. flavipes. B. M. mundanus. C. M. filipes.

Fig. 3. Male median lobe and parameres of Mecyclothorax spp. A. M. flavipes, right lateral view. B. M. flavipes, ventral view. C. M. filipes, right lateral view. D. M. filipes, ventral view. E. M. filipes, right lateral view, internal sac everted. Abbreviations: af, apical face of tip; dop, dorsal ostial microtrichial patch; dp, dorsal plate; sc, sagittal crest of basal bulb.

Fig. 4. Female reproductive tracts (A, C) and gonocoxa (B, D) of Mecyclothorax spp. A, B. M. flavipes. C, D. M. filipes. Abbreviations: alf, apicolateral fringe setae; am, apicomedial seta; an, apical nematiform setae; bc, bursa copulatrix, co, common oviduct; de, dorsal ensiform seta; dl, dorsal lobe of bursa copulatrix; gc1, basal gonocoxite 1; gc2, apical gonocoxite 2; le, lateral ensiform setae; sg, spermathecal gland; sp, spermatheca; vl, ventral lobe of bursa copulatrix.

Fig. 5. Known distributions of carabid beetle species on Lanai. A. Mecyclothorax flavipes. B. M. mundanus. C. M. filipes. D. Bembidion ignicola. E. Blackburnia lanaiensis. F. Bl. lucipetens.

Fig. 1. Pre-Polynesian vegetation communities on the island of Lanai (after Hobdy 1993): 1) cloud forest; 2) mesic forest; 3) dry forest; 4) arid grassland and shrubland; 5) coast and strand.