Mecyclothorax laterosinuatus Liebherr, 2018
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publication ID |
https://dx.doi.org/10.3897/dez.65.21000 |
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publication LSID |
lsid:zoobank.org:pub:73DEE0F3-2BB0-4A21-B445-5E168FE50F54 |
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persistent identifier |
https://treatment.plazi.org/id/BC6BAC70-3131-45CD-B8DE-0D72BB0D70A3 |
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taxon LSID |
lsid:zoobank.org:act:BC6BAC70-3131-45CD-B8DE-0D72BB0D70A3 |
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treatment provided by |
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scientific name |
Mecyclothorax laterosinuatus Liebherr |
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sp. n. |
2. Mecyclothorax laterosinuatus Liebherr sp. n. Figures 9B View Figure 9 , 10C-E View Figure 10 , 11A View Figure 11 , 12B View Figure 12 , 13B View Figure 13 , 14 View Figure 14
Diagnosis.
These beetles are very similar in external appearance to those of M. laterorectus (Fig. 9B-C View Figure 9 ) below, sharing the moderately robust body form and cordate pronotum, though the pronotal base is slightly broader relative to the maximal pronotal width in this species: MPW/BPW = 1.28-1.33. This species also differs from M. laterorectus in the very shallow second elytral stria contrasted to the deeper sutural stria and striae 3-6. Like the preceding M. laterobustus , the pronotal hind angles protrude, with the pronotal lateral margin concave before the angle, but in this species and the following, the pronotal lateral seta is present. Also, this and the following species exhibit both anterior and posterior supraorbital setae. Standardized body length 3.7-4.3 mm. Chaetotaxy +/+//+/-//+/2/+/+.
Description
(n = 5). Head capsule broad, eyes convex, ocular lobe meeting gena at obtuse angle very close to eye posterior margin; 12-14 ommatidia along horizontal diameter of eye; ocular ratio 1.43-1.50, ocular lobe ratio 0.84-0.89, EyL/EyD = 2.50-2.65; frontal grooves nearly straight from posterior terminus inside anterior supraorbital seta to deepest point just posterad clypeus, briefly and shallowly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.8; ligular anterior margin narrowly rounded to ligular seta, concave between setae, the two setae separated by two setal diameters; paraglossae thin, extended as far beyond ligular margin as their basal length to margin; antennae elongate, antennomere 9 length 2.25 × maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum distinctly constricted basally, cordate, hind angles obtuse rounded, lateral pronotal margins subparallel anterad hind angles, then distinctly divergent anteriorly (Fig. 9B View Figure 9 ); MPW/BPW = 1.37-1.40, MPW/PL = 1.24-1.27; front angles protruded, obtusely angulate, APW/BPW = 0.75-0.78; basal margin slightly convex, nearly straight between broadly upraised hind margins posterad broad laterobasal depressions; laterobasal depression with longitudinal tubercle inside hind angle, and broad furrowlike longitudinal extension onto disc; median longitudinal impression fine and shallow on disc, with deep longitudinal pitlike depression anterad median base, absent anterad very broad and shallow anterior transverse impression; proepisternum separated anteriorly from prosternum by fine shallow groove, distinctly separated ventrally by smooth, deep groove; prosternal process deeply, narrowly between procoxae, that deep depression extended 1/3 distance toward anterior prothoracic margin. Elytra broadly ellipsoid, humeri extended laterally, humeral angle obtusely rounded outside pronotal hind angles; MEW/EL = 0.81-0.86; basal groove evenly arcuate from scutellum to humeral angles, with depressions at bases of sutural and elytral striae 3-5; sutural stria deep throughout length, stria 2 shallow, obsolete on disc, striae 3-5 deep, stria 6 shallow, and stria 7 obsolete in basal half; striae 1-2, 7 and 8 evident apically, elytra appressed and conjoined apically, sutural intervals narrower and upraised at apex. Pterothoracic mesepisternal anterior furrow with five broad depressions in one to two vertical rows; metepisternum maximum width/lateral length = 1.1; mesosternal-mesepisternal suture complete (as in Fig. 3A View Figure 3 ); metepisternal-metepimeral suture incomplete, shallower and incomplete laterally. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, second ventrite depressed within crescent; suture between second and third ventrites reduced, incomplete laterally; ventrites 2-6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons an evident transverse mesh, transverse sculpticells mixed with isodiametric sculpticells on vertex; pronotal disc and base covered with elongate transverse mesh plus transverse lines, surface iridescent; elytra iridescent, disc with loose elongate transverse mesh, apex with very elongate transverse mesh, sculpticell breadth 3-4 × length. Femora rufobrunneous basally, with a broad flavous band in apical third.
Male genitalia (n = 5). Antecostal margin of abdominal mediotergite IX angulate distally, an elongate distal extension present (Fig. 10E View Figure 10 ); right paramere very elongate, apical half narrowed into a whiplike extension (Fig. 11A View Figure 11 ), with 10 setae on ventral surface complementing the two apical setae, dorsal surface with four small setae; left paramere narrow basally, evenly extended to whiplike apex, surfaces glabrous except for two apical setae; aedeagal median lobe robust, broad dorsoapically, apex broadly curved ventrally with tip rounded (Fig. 10C-D View Figure 10 ); aedeagal median lobe internal sac with flagellum, flagellar sheath, and dorsal plate, the former two structures curved dorsad apically. The median lobes of the two figured males-Col d’Amieu (Fig. 10C View Figure 10 ) and Touho TV Tower (Fig. 10D View Figure 10 ) - differ about 10% in length, whereas the males themselves are nearly identical in standardized body length; 4.0 versus 4.05 mm. As the internal sac structures do not appear to differ except in the basal shape of the dorsal plate (differing orientation inside median lobe?), these two populations are considered conspecific.
Female reproductive tract (n = 2). Bursa copulatrix elongate, length about twice circumference, surface translucent, membranous (Fig. 12B View Figure 12 ); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct as long as spermathecal reservoir; an elongate laminar helminthoid sclerite present at base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present near base of common oviduct; basal gonocoxite 1 with apical fringe of one to two short setae laterally on apical margin, smaller microsetae scattered along apical margin, and a series of small setae lining medial margin (Fig. 13B View Figure 13 ); gonocoxite 2 broad basally, basal width slightly more than half medial length; two short, gracile lateral ensiform setae present.
Types - Holotype male (MNHN): NEW CALEDONIA / Aoupinie top camp / 2-3Nov 2001 / G.B.Monteith // QM Berlesate 1060 / 21°11 ’Sx165°18’ / Rainforest, 850m / Sieved litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // New Caledonia Mecyclothorax revision / measured specimen 2 / J.K. Liebherr 2016 // HOLOTYPE / Mecyclothorax / Mecyclothorax laterosinuatus / J.K.Liebherr 2017 (black-bordered red label).
Paratypes (83 specimens; BPBM, MNHW, PMGC, QMB): see Suppl. material 2.
Etymology.
Like the preceding and immediately following species, beetles of this species exhibit a basally broad pronotum (Fig. 9A-C View Figure 9 ). In this species, the distinctly sinuate lateral pronotal margin leads to the compound adjectival species epithet Mecyclothorax laterosinuatus .
Distribution and habitat.
This species is broadly distributed along mid-latitudinal Grand Terre, from Touho TV tower on the north to Mt. Rembai on the south (Fig. 14 View Figure 14 ), with beetles found from 400 m elevation to the summits of the occupied uplands. Of the 76 known specimens, 67 have been collected from sieved litter, indicating occupation of the ground-level microhabitat. Exceptions with situational label data include a singleton found via headlamp search at night (Will, EMEC), and two beetles collected from two flight-intercept traps (Monteith, QMB; Théry, MNMH), no doubt after crawling into the collecting tray.
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