Mecodema haunoho Seldon & Leschen, 2011

Seldon, David S. & Buckley, Thomas R., 2019, The genus Mecodema Blanchard 1853 (Coleoptera: Carabidae: Broscini) from the North Island, New Zealand, Zootaxa 4598 (1), pp. 1-148 : 53-55

Mecodema haunoho Seldon & Leschen, 2011 .

Figures 4 , 15B and 30 .

Diagnosis: Distinguished from other North Island Mecodema species by having: 1, the prothoracic carina narrow the entire length, moderately crenulated with 3 setae along each side (curviden s species group); 2, distinctive shape of the penis lobe ( Fig. 30 PL).

Description: Length 20.5–24.1 mm, pronotal width 5.1–5.9 mm, elytral width 6.3–6.8 mm. Colour of entire body matte to glossy black.

Head: Narrow and flat ( Fig. 14C ). Vertex with very fine wrinkles forming an isodiametric pattern (may be indistinct); vertexal groove narrow and well-defined the entire length; small supraorbital puncture bearing 2–3 setae; 1–2 well-defined supraorbital grooves (especially the one that encompasses the supraorbital puncture); frons with a large and shallow depression each side of midline ( Fig. 30 ); frontoclypeal suture well-defined, tentorial pits absent; anterior area of clypeus ( Fig. 9 ) with shallow and narrow grooves, very faint in some specimens; clypeus with 1 setose puncture each side bearing 2 setae. Labrum rectangular, anterior edge outwardly curved with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes squared ( Fig. 12G ), median process short and narrow, slightly angled upward (15°), notched indentation ( Fig. 12D ); mentum setae variably present or absent. Submentum sclerite constriction narrow with 6–8 setae, medial setae pair distantly spaced, 2 lateral setae pairs anterad the others. Stipes with 2 basal setae. Gula pits ( Fig. 8 ) large, suture poorly defined, gula flat and smooth. Gena with fine wrinkles forming an isodiametric pattern across entire area.

Prothorax: Prothoracic carina narrow the entire length, moderately crenulated with 3–4 setae along each side ( Fig. 30 ), extended beyond anterior angle; posterior lateral sinuation evidently carinate, slightly angled inward; pronotum broad and laterally deflected, overall shape squared; midline weakly impressed, medial impressions absent, disc with very fine wrinkles laterally; pronotal foveae shallow and narrow; anterior edge slightly inwardly curved, posterior edge slightly inwardly curved medially. Prosternum ( Fig. 2 ) flat and smooth; proepisternum with indistinct wrinkles. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Narrow and slightly deflected; humeral angle evenly convex ( Fig. 6B ), basal margin slightly curved and bevelled to base, interval 1 extended to margin; lateral carina narrow the entire length, extended to humeral angle; humerus with 2 setose punctures within angle ( Fig. 30 ); suture impressed but no more so than striae; striae with small, regularly spaced asetose punctures; intervals 1–4 slightly convex, 5–8 moderately convex, interval 9 strongly convex; interval microsculpture absent; 7 th strial setal pattern with 0–1 setose puncture in anterior ½, 4 setose punctures in posterior ½ ( Fig. 30 ), setose punctures small.

Ventral surface: Mesepisternum and metepisternum with corrugose wrinkles; setose punctures of mesocoxae ( Fig. 2 ) and metacoxae absent. All abdominal ventrites finely lineate; ventrites 3–5 setose punctures absent each side of midline; ventrite 6 setae present: ♂ with 2 setose punctures each side of straight portion of apical edge, ♀ with 2 setose punctures each side, distantly spaced at edge of bluntly rounded apical edge; lateral foveae absent. Anterior metaventrite process a short rounded triangle with a very broad (apically) and distinctly defined carina.

Male genitalia: Apical portion of penis lobe symmetrically rounded with a moderate deflection to right of vertical axis (VV) ( Fig. 15B ), dorsal process slightly more flattened than ventral apical curve ( Fig. 30 PL); overall length of penis lobe shaft with curve to right absent (VV); overall length of penis lobe shaft short and broad, moderately curved ventrally (LV) ( Fig. 16B ). Structures of the endophallus ( Fig. 4 ): lateral form of the apex of the central spicule pointed; dorsal form of the apex of the central spicule short and narrow; setal (scales) coverage of the apical plate moderate (26–75%); size of left setose flange small; size of right setose flange large. Left paramere basal lobe a very slender rectangle (only slightly broader than right paramere), short slope to arm ( Fig. 30 LP); arm relatively long and broad, gradually narrowed to terminal lobe; short and narrow terminal lobe with a tuft of medium length setae ( Fig. 30 LP); sparse shorter setae extend along apical ¾ of ventral edge; ventral edge straight. Right paramere narrow and triangular with setae extending along apical ¾ of ventral edge ( Fig. 30 RP).

Female genitalia: Basal gonocoxite 1 short and broad, apically flattened with a few grooves present on ventral surface, internal dorso-lateral carina with 1 seta. Gonocoxite 2 ( Fig. 5 ) a short, broadly rounded triangle, apical edge strongly reflexed. Ramus long and relatively broad.

Comments: Mecodema haunoho is endemic to Te Hauturu-o-Toi/Little Barrier Island, and its very close sister taxa, M. aoteanoho is endemic to Aotea.

Distribution: New Zealand, North Island, Coromandel, Te Hauturu-o-Toi/Little Barrier Island (only).

Holotype: NZAC, male labelled: NEW ZEALAND CL, Little Barrier Island , Tirikakawa Stream, 2005, D.S. Seldon ♂ / HOLOTYPE Mecodema haunoho n. sp. design. by Seldon & Leschen 2010 [red label].

Paratypes: (see Seldon & Leschen 2011).

Material examined: 1♀, NEW ZEALAND CL, Little Barrier Is., Awaroa Stream PTs 22.11.06 – 22.1.07, D.S. Seldon / NZAC04127983 .

Figures

FIGURE 2. Ventral view of a Mecodema specimen showing specific morphological structures, excluding taxonomic structures indicated in detail figures, used in the species descriptions. ƑLF = ventrite lateral foveae; ƑSP = ventrite setose punctures; MTC = metacoxa; MTƑP = metaventrite process; MSC = mesocoxa; PC = procoxa; PS = prosternum; G = gena; PES = proepisternum; MSE = mesepisternum; MTE = metepisternum; Ƒ1–Ƒ6 = ventrites 1-6 (ventrites 1-3 may be fused); M = midline (dashed line, not a taxonomic structure).

FIGURE 4. An Environmental Scanning Electron Microscope (ESEM) photograph of the four main structures of the apical plate of the endophallus within the penis lobe. This is an example from Mecodema haunoho showing the central spicule (c.s), left (l.s.f) and the right setose flange (r.s.f), and microtrichial field (m.f). These structures are variable among species but within a species, they are very consistent, even over distant geographical ranges. The microtrichial field can be covered in flattened scales as in photo above, or with elongated setae-like scales.

FIGURE 5. The entire female reproductive tract (ventral view) including taxonomic structures (for all other abbreviated structure names see Seldon et al. 2012). However, for this revision only the following structures are important: HS = helminthoid sclerite; G1 = gonocoxite 1; G2 = gonocoxite 2; TDC = transverse dorsal carina; R = ramus.

FIGURE 6. Detail of the three different forms of the elytral humeral angle: (A) = anteriorly convergent (M. parataiko), (B) = evenly convex (M. oconnori), (C) = subangulate (M. atuanui).

FIGURE 8. Detail of the ventral head with the taxonomic structures used in the species descriptions. SBMS = submentum setae; SBM = submentum sclerite; ML = mentum lobe; MP = mentum process (with indentation); MPW = mentum process width; SBS = stipes basal setae; MPL = mentum process length; MPS = mentum process setae; SBMC = submentum sclerite constriction; GP = gula pits; GS = gula suture.

FIGURE 9. Dorsal view of head with detail of the morphological structures used in the species descriptions. Ƒ = vertex; SPS = supraorbital puncture setae; SP = supraorbital puncture; F = frons area; FCS = frontoclypeal suture; C = clypeus; M = mandible; LS = labrum setae; L = labrum; ACM = anterior clypeal microsculpture; CSP = clypeal setose puncture; TP = tentorial pit; SG = supraorbital grooves; E = eye; ƑG = vertexal groove.

FIGURE 10. The protibia form is a character used mainly to determine between genera, except for one species in Mecodema where the difference between (A) greatly distally expanded (M. antarctica) and (B) expanded distally (all other Mecodema species) is used.

FIGURE 12. Ventral view of the mentum with a number of different character states. Illustrations A–D are the different forms of the indentation in the apex of the median process: (A) distinctly indentate (M. manaia); (B) moderately indentate (M. pluto); (C) slightly indentate (M. infimate); (D) indentation notched (M. parataiko). Illustrations E–G are the three general forms (i.e., hashed lines) of the mentum lobes: (E) triangular; (F) rounded; (G) squared.

FIGURE 14. Diagrammatic cross sections that represent the width and convexity of head or deflection of pronotum (frontal view): (A) broad and flat; (B) broad and convex; (C) narrow and flat; (D) narrow and convex.

FIGURE 15. The penis lobe in ventral view showing the relative deflection to right of vertical: (A) distinctly deflected (M. regulus); (B) moderately deflected (M. haunoho); (C) slightly deflected (M. oregoides). Scale bars = 1 mm. Structures of penis lobe indicated are: base (B); lateral edge (LE); apical portion (AP); ventral edge (ƑE).

FIGURE 16. Relative strength of the ventral curve over the length of the penis lobe (lateral view): (A) slightly curved (M. oblongum); (B) moderately curved (M. ponaiti); (C) distinctly curved (M. manaia). Scale bar = 1 mm.

FIGURE 30. Mecodema haunoho plate with half habitus (left) and the three (detached) structures of the male aedeagus: the right (RP) and left parameres (LP), plus the penis lobe (PL). The bottom scale bar is the width across the widest point of the pronotum of the specimen used for this habitus and top scale bar equates to the half the length of the penis lobe.