Mecyclothorax filipes: Britton 1948: 136

Liebherr, James K., 2009, Native And Alien Carabidae (Coleoptera) Share Lanai, An Ecologically Devastated Island, The Coleopterists Bulletin 63 (4), pp. 383-411 : 396-397

Mecyclothorax filipes: Britton 1948: 136 .

Diagnosis. In the M. palustris group, this species stands out from all others based on the very well-developed isodiametric elytral microsculpture that produces a roughened surface on the elytral disc ( Fig. 2C ). In contrast to the granulate elytra, the pronotal disc and head are glossy, with only intermittent areas of transverse mesh microsculpture visible on the pronotal disc, though the areas between the distinct punctures on the pronotal median base are covered with isodiametric sculpticells. The pronotal base is narrow between the sinuate laterobasal margins and sharply angulate hind angles, with the ratio of maximum pronotal width to basal pronotal width 1.58–1.62. Only the first elytral stria is well-developed in all observed individuals, with striae 2–4 or 2–5 progressively shallower laterally on disc, indistinctly punctate in some individuals to smooth in others, and striae 5–7 or 6–7 marked only by series of indistinct punctures (not visible at all in some individuals). The male aedeagal median lobe apex sinuously extends past the ostial opening approximately half the length of the internal sac ( Fig. 3C–E ), a conformation shared with M. annae Liebherr (2006 b : Fig. 69) of Molokai. However, M. annae exhibits the elytral strial conformation of the M. ovipennis group—stria 1 and 2 subequally developed apically—and also differs by: 1) smaller body size (standardized body length 3.8–4.5 mm versus 4.5–5.5 in M. filipes ); 2) very narrow body ( Liebherr 2006 b: Fig. 15); and 3) smaller eyes (ocular ratio 1.45–1.49 versus 1.50–1.55 in M. filipes ).

Male genitalia (n 5 20). Aedeagal median lobe gracile, median dorsoventral breadth 0.17 3 distance from tip to distal margin of sagittal crest ( Fig. 3C ); median lobe apex sinuously extended, the apex recurved basad the evenly downturned tip ( Fig. 3C, E ); lobe apex in ventral view extended from right side of lobe, with small constriction of right side from body of lobe to attenuate apex ( Fig. 3D ); median lobe internal sac indistinctly spiculated, a small, lightly sclerotized dorsal ostial microtrichial patch present ( Fig. 3C–E ); dorsal plate of sac small, lightly sclerotized, sac length 0.21 3 distance from tip to distal margin of sagittal crest.

Female reproductive tract (n 5 4). Bursa copulatrix elongate, bursal length from line between bases of gonocoxae to apex 2.8–4.0 3 greatest width (pressed flat under coverslip), ( Fig. 4C ); bursal surface membranous, staining with Chlorazol Black less intensely than base of common oviduct, suggesting oviduct base is thicker; spermathecal duct relatively short, length about twice that of gonocoxa; spermathecal gland duct relatively short, length less than that of apical gland reservoir; gonocoxite 1 with apical fringe of three to four setae (bilaterally variable), an apicomedial seta, and approximately five setae along mesal margin ( Fig. 4D ); gonocoxite 2 robust, broad basally, with basolateral margin recurved anteriorly; two lateral ensiform setae broad and relatively long, one dorsal ensiform seta and two apical nematiform setae also present.

Type. Lectotype male ( BMNH) card mounted, and labeled: Type D.S. Lanai Perkins (on obverse), 134 (on reverse) / Type / Hawaiian Is. Perkins 1904-336 / Halepaakai Lanai Perkins VII 1894 / Lectotype Thriscothorax filipes Sharp J.K. Liebherr 1998 (black-bordered red label). This lectotype is designated because the syntype series is divided between BMNH and BPBM ( Manning 1986) and nearly all other lectotypes of Fauna Hawaiiensis Carabidae are deposited at BMNH.

Distribution. This species is recorded from numerous localities along Lanai’s summit ridge ( Fig. 5C ), including from northwest to southeast: Kaiholena Gulch and above, Waialala Gulch, Puu Aalii, Hauola Ridge, Lanaihale, Haalelepaakai, Lehua and Waiakeakua, all of these within the cloud forest community ( Fig. 1 ). The sole locality in the mesic forest zone is in Kaiholena Gulch, where Perkins collected it at about 600 m el. (lots 78 and 87, both cited as‘‘Lanai, behind Koele II. ’94’’; Anonymous N.D.). During his trip, Giffard found the species only at Haalelepaakai ( Giffard 1908). Records from 1987 to the present are from collecting sites 750–1,030 m elevation.

Habitat. This is by far the most abundant Mecyclothorax species collected during all periods on Lanai, with 286 specimens recorded versus a sum of 6 for the other two species. This species is also known from a variety of plant substrates. Beetles have been beaten from ferns including Cibotium glaucum (Smith) , Sadleria Kaulfuss sp. , and Dicranopteris linearis (Burm. F.) or uluhe fern ( Palmer 2003), plus a variety of unidentified soft understory ferns. Native plant taxa recorded as substrates for beetles include Antidesma L., under rotten bark of Cheirodendron Nuttall , Clermontia arborescens (H. Mann) , Dubautia Gaudichaud-Beaupre´, Gouldia A. Gray , Melicope J. R. and G. Forster, under moss and lichens on ohia, in moss on Straussia A. P. de Candolle , and from Tetraplasandra A. Gray. One beetle was collected on the bark of non-native Casuarina in the company of M. flavipes . On 13 May 2004 (lot 01, CUIC), M. filipes was collected by beating uluhe fern near Haalelepaakai (CUIC) in the company of the native B. depressa and the non-native platynine Metacolpodes buchanani (Hope) . That same day and locality, four species were beaten from soft understory ferns (lot 02, CUIC): the natives M. filipes , B. depressa , and B. filipes and the non-native Gnathaphanus picipes (MacLeay) .

Native Carabid Beetle Species

Tribe Bembidiini

Diagnosis. Within the Hawaiian carabid beetle fauna, members of this tribe are diagnosed by: 1) conjunct mesocoxal cavities; 2) presence of a seta in the mandibular scrobe; and 3) subulate ultimate labial and maxillary palpomeres that are narrower and shorter than the penultimate palpomeres (Liebherr and Zimmerman 2000). The Hawaiian bembidiine fauna includes species placed in Bembidion (subtribe Bembidiina ), Elaphropus Motschulsky , Lymnastis Motschulsky , and Tachys Dejean (subtribe Tachyina ), and Typhlonesiotes Jeannel (subtribe Anillina ). Species of Bembidion can be diagnosed from taxa in Tachyina by the lack of a recurrent sutural stria on the elytral apex, and from taxa in Anillina by the restriction of the lateral elytral setae to laterad the depressed eighth stria, not more loosely associated with each other and distributed across the outer two to three intervals as in Anillina ( Jeannel 1941) . Liebherr (2008 a) taxonomically revised all Hawaiian Bembidion species.

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.