Mecyclothorax mundanus (Sharp)

Liebherr, James K., 2009, Native And Alien Carabidae (Coleoptera) Share Lanai, An Ecologically Devastated Island, The Coleopterists Bulletin 63 (4), pp. 383-411 : 394-395

Mecyclothorax mundanus (Sharp) ( Figs. 2B , 5B )

Thriscothorax mundanus Sharp, 1903: 261 .

Mecyclothorax mundanus: Britton 1948: 137 .

Diagnosis. The only species on Lanai with elytral stria 2 nearly as deep and broad apically as the sutural stria. The pronotum has broadly reflexed lateral margins that are distinctly sinuate before the nearly right hind angles, and the base is relatively narrow, with the ratio of maximum pronotal width to basal pronotal width 1.59 ( Fig. 2B ). Mecyclothorax mundanus appears most similar to M. joni Liebherr of Molokai— M. mundanus specimens will key to M. joni in Liebherr (2006 b) —sharing the pronotal proportions, setation, and body size, however specimens of M. mundanus have: 1) less developed eyes (ocular ratio 1.51 versus 1.57–1.58); 2) broader pronotal lateral margins; 3) more transverse microsculpture without any tendency to form an isodiametric mesh; and 4) less developed elytral striation, with only stria 1–5 impressed, versus 1–6 plus a shallowly traceable stria 7 present in M. joni . Standardized body length 4.0– 4.5 mm.

Female reproductive tract. I did not dissect the lone female paratype that I was able to study intensively.

Types. Lectotype female ( BMNH) card mounted, labeled: Type D.S. Lanai Perkins 135 / Type / Hawaiian Is. Perkins 1904-336 / Lanaihale Lanai summit Perkins VII 1894 / Lectotype Thriscothorax mundanus Sharp J.K. Liebherr 1998 (black-margined red label). A single female paralectotype ( BMNH) with left protarsomeres broken off ( Fig. 2B ) has been so labeled . Lectotype designation establishes a single complete specimen as arbiter of the type concept for this species.

Distribution. Known only from the summit of Lanaihale, which sits at 1,030 m above sea level ( Fig. 5B ).

Habitat. At the time Perkins collected this species, Lanaihale summit would have been largely populated by native trees such as ohia ( Metrosideros polymorpha Gaudichaux-Beaupre´); any reforestation efforts with non-native species still being in the future. The forest he visited was disturbed by foraging pigs: ‘‘On July 5th I moved camp to Halepaakai [Haalelepaakai immediately SE of Lanaihale], it had taken up for me on a mule by Macfarlane, as far as the animal could go, about 6 or 8 gallons of water, there being no standing water on the top except in some pig wallows’’ (Perkins in Evenhuis 2007: 236). These feral pigs would have been from the first introduction of European hogs to the island in the late 1880’s, before their descendants were killed off by a ‘‘virulent hog cholera epidemic’’ ( Hobdy 1993: 206). During this July stay on the summit, Perkins collected M. mundanus , M. filipes , B. depressa , and B. filipes (Liebherr 2000) .

Mecyclothorax palustris species-group

Diagnosis. Species of this group have the inner 1–3 to 1–5 striae evident on the elytral disc, but with striae more reduced both laterally and apically. The sutural stria is deep and smooth on the elytral apex, but the second stria is much shallower, though it may be traceable to the apex. Additionally this group is diagnosed by: 1) pronotum basally sinuate with beaded to broader and upturned lateral margins, and distinct hind angles; 2) pronotum setose with either lateral seta present, or both lateral and basal setae present; 3) eyes moderately convex to well developed, but not hemispherical and highly convex; 4) elytra with distinct, well-developed isodiametric or transverse microsculpture; and 5) body size moderate, standardized body length 4.0–6.0 mm. In addition to the single Lanai species, the group includes a single species from Oahu (Liebherr 2009), three species from Molokai ( Liebherr 2006 b), one described species from Maui ( Britton 1948), and four species from Hawaii Island ( Liebherr 2008 b).

Figures

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

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.