Mecodema teroroa, Seldon & Buckley, 2019

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 : 119-121

Mecodema teroroa sp. n.

Figure 58 .

Diagnosis: Distinguishable from other North Island Mecodema by: 1, a raised ridge with corrugose wrinkles anterad vertexal groove, punctures along entire length; 2, humeral angle subangulate; 3, basal margin slightly curved and shortened (½ length), bevelled to base; 4, the unique distribution of setae along the ventral edge of the left paramere ( Fig. 58 LP).

Description: Length 28–32.4 mm, pronotal width 6.6–8.9 mm, elytral width 8–10.8 mm. Colour of entire body brown to black, ventrally dark reddish-brown to matte black.

Head: Broad and flat ( Fig. 14A ). Vertex with very fine lines forming an isodiametric pattern laterally, otherwise smooth; vertexal groove well-defined, broadened laterally, punctured entire length ( Fig. 58 ); corrugate wrinkles anterad groove; large supraorbital puncture bearing 4–6 setae; 3–4 well-defined supraorbital grooves; frons with small, rounded and shallow depressions laterally, grooves may be present antero-laterally; frontoclypeal suture poorly defined, tentorial pits small to indistinct; anterior area of clypeus ( Fig. 9 ) medially convex between punctures, poorly defined grooves, 1 setose puncture each side and 1 medial setose puncture, all bearing 2 setae ( Fig. 58 ). Labrum lobate, anterior edge strongly emarginated medially with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded ( Fig. 12F ), median process short and broad, moderately angled upward (30°), moderately indentate ( Fig. 12B ); mentum setae ( Fig. 8 ) absent. Submentum sclerite constriction broad with 3 evenly spaced setae each side. Stipes with 2 basal setae. Gula pits small, suture well-defined but not deep the entire length, gula flat with fine transverse lines. Gena ( Fig. 8 ) with fine wrinkles forming an isodiametric pattern across entire area but more impressed laterally.

Prothorax: Prothoracic carina broad the entire length, especially anterior ⅓, crenulations absent with 8–12 setae each side ( Fig. 58 ), extended beyond anterior angle; posterior lateral sinuation ( Fig. 11 ) evidently carinate, slightly angled inward; pronotum broad and flattened, overall shape broadly cordate; midline well-defined, anterior medial triangular depression and posterior medial diamond-shaped impression present, disc covered with very fine transverse wrinkles ( Fig. 58 ), very shallow, small and round depression present each side of midline anterad foveae; pronotal foveae very shallow and broad; anterior edge inwardly curved, posterior edge straight. Prosternum ( Fig. 2 ) flat with very fine, well-spaced transverse lines; proepisternum without microsculpture. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Broad and flat, slightly deflected laterally; humeral angle subangulate ( Fig. 6C ); basal margin slightly curved, truncated (½ length) and bevelled to base, interval 1 extended to margin; lateral carina relatively broad, gradually broadened to meet humerus and apex, extended beyond humeral angle; humerus with 2–3 setose punctures, proximate the angle ( Fig. 58 ); suture moderately impressed; striae 1–4 with indistinct asetose punctures, striae 5–8 with setose punctures more defined, all asetose punctures small and regularly spaced; intervals wide and flat, convexity increased laterally (slightly convex); interval microsculpture present as fine transverse lines; 7 th strial setal pattern with 2–3 setose punctures in anterior ½, 4–5 setose punctures in posterior ½ ( Fig. 58 ), setose punctures small.

Ventral surface: Mesepisternum with a few grooves and obsolescent punctures; metepisternum ( Fig. 2 ) without microsculpture (some specimens very faintly micropunctate); setose punctures present on mesocoxa (2) and metacoxa (2–3). All abdominal ventrites lineate laterally; ventrites 3–5 ( Fig. 2 ) with 1 setose puncture each side of midline, ventrite 6 setae present: ♂ with 1 setose puncture each side located wide at junction of straight apical edge and curve anterad, ♀ with 2 setose punctures each side evenly-spaced along bluntly rounded apical edge; ventrites foveate laterally. Anterior metaventrite process a short triangle with carina apically broad to laterally narrowed.

Male genitalia: Apical portion of penis lobe asymmetrically hooked with distinct deflection to right of vertical axis (VV) ( Fig. 15A ); ventral process short and pointed ( Fig. 58 PL), apex asymmetrically curved upward to form dorsal process (Trounson specimens with ventral portion of asymmetrical curve more pronounced), dorsal process long (slightly longer in Trounson population) and narrow, moderately recurved (more pronounced in Waipoua population), then briefly curved to shaft ( Fig. 58 PL); ventral edge of penis lobe straight (VV), shaft of penis lobe narrow the entire length; overall length of penis lobe definitely curved ventrally (LV) ( Fig. 16C ). Structures of the endophallus ( Fig. 4 ): lateral form of the apex of the central spicule rounded; dorsal form of the apex of the central spicule greatly expanded with projection; setal (scales) coverage of the apical plate moderate (26–75%); size of left setose flange small; size of right setose flange very long. Left paramere basal lobe articulated at right angle to penis lobe, rectangular with moderate dorsal hump forming a steep (60°) slope to arm ( Fig. 58 LP); arm short and narrow (ventral edge of arm curved anterad); terminal lobe indistinct from arm with an apical tuft of long setae, comb of long setae in curvature of arm ( Fig. 58 LP), ventral edge straight. Right paramere broadly rectangular ( Fig. 58 RP) with a double row of long setae extended along apical ½ of ventral edge, apical portion distinctly inwardly curved across penis lobe.

Female genitalia: Basal gonocoxite 1 short and broad, ventral surface smooth, internal dorso-lateral carina with 2 setae. Gonocoxite 2 ( Fig. 5 ) broadly triangular, apical edge recurved upward. Ramus long and broad.

Comments: Mecodema teroroa is found from the Hokianga Harbour to the Tutamoe Range, but does not extend eastward further than foothills of the Parataiko Range.

Distribution: New Zealand, North Island, Northland, Parataiko Range, Waipoua Forest, Trounson Forest.

Holotype: LUNZ male labelled. NEW ZEALAND ND, Trounson Kauri Park , 21.viii.1996, G.L.F. Carlin, pitfall traps in kauri forest / HOLOTYPE Mecodema teroroa n. sp. design. DS Seldon, TR Buckley 2018 [red label].

Paratypes: 1♀, NEW ZEALAND ND, Waipoua F., Yakas tk, 6-11.II.1995, Larivière. Larochelle / pittraps taraire-kauri for., wet soil ( NZAC); 1, NEW ZEALAND, ND, Waipoua Forest , 4 Nov 1998, AM Booth / NZMS 260 Q06 653 138, on ground / AMNZ 40703 [green label]; 1, Waimatenui , 22-10-32, E. Fairburn / C.E. Clarke Collection / AMNZ 40752 [green label]; 1, Waimatenui / C.E. Clarke Collection / AMNZ 40749 [green label]; 1, Waimatenui , 11-10-32, C.E. Clarke / C.E. Clarke Collection / AMNZ 40753 [green label]; 1, Waipoua, 2.5 miles S.W. of Waimatenui, Cranfield, RS #97 31.v.69 roadside bush / 2007.163.10894 ( CMNZ) ; 1♂, 2496 Waipoua, Waimatenui, Waioko road, Johns, PM 22.iii.99 logs, etc / 2007.163.10865 ( CMNZ) ; 1♂, Waipoua Forest Sanctuary Kathleen Smith, Oct 1984 pittraps in kauri forest / 2007.163.10892 ( CMNZ) .

Etymology: Mecodema teroroa is named after Waipoua Forest’s traditional guardians, Te Iwi o Te Roroa.

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 11. Detail of pronotum showing the taxonomic structures used in the species descriptions. PPC = posterior pronotum constriction; PS = pronotal setae; PAA = pronotum anterior angle; AE = anterior edge; PC = pronotal carina; ML = midline; PF= pronotal foveae; PPS = pronotum posterior sinuation; PE = posterior edge.

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 58. Mecodema teroroa 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.