Mecodema parataiko 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 : 88-90

Mecodema parataiko Seldon & Leschen, 2011 .

Figures 6A , 12D and 45 .

Diagnosis: Distinguishable from other North Island Mecodema species by having: 1, 4–6 setae along the prothoracic carina ( curvidens species group); 2, elytral humerus without setose punctures; 3, all elytral striae with large, irregularly spaced asetose punctures ( Fig. 45 ).

Description: Length 19.3–22 mm, pronotal width 5–5.7 mm, elytral width 5.8–6.9 mm. Colour of entire body matte to glossy black, coxae may be dark red.

Head: Narrow and flat, deflected laterally ( Fig. 14C ). Vertex with a few rugose wrinkles laterally; vertexal groove narrow and well-defined medially, shallowly impressed laterally; large supraorbital puncture bearing 3–4 setae; 2–3 well-defined supraorbital grooves; frons ( Fig. 9 ) convex medially with a small and shallow depression each side, shallow grooves may be present laterally; frontoclypeal suture defined, tentorial pits small; anterior area of clypeus with indistinct broad grooves, 1 deep setose puncture each side bearing 2 setae ( Fig. 45 ). Labrum rounded, anterior edge straight with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes squared ( Fig. 12G ), median process long and narrow, upward angle absent, notched indentation ( Fig. 12D ); mentum setae present. Submentum sclerite constriction broad with 3 setae clustered laterally (very wide gap medially). Stipes with 2 basal setae. Gula pits small, suture poorly defined, gula flat and smooth. Gena ( Fig. 8 ) with rugose wrinkles forming an isodiametric pattern laterally.

Prothorax: Prothoracic carina broad the entire length, moderately crenulated with 4–6 setae each side ( Fig. 45 ), extended to anterior angle; posterior lateral sinuation evidently carinate, inwardly angled; pronotum broad and moderately deflected laterally, overall shape squared ( Fig. 45 ); midline impressed, anterior medial and posterior medial impressions absent, disc with transverse wrinkles laterally ( Fig. 45 ); pronotal foveae deep and narrow; anterior edge distinctly inwardly curved, posterior edge straight. Prosternum flat and smooth; proepisternum with corrugose ridges. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Narrow and moderately deflected; humeral angle anteriorly convergent ( Fig. 6A ); basal margin moderately curved and bevelled to base, interval 1 extended to scutellum; lateral carina narrow the entire length but broadened in posterior ⅓, extended to humeral angle; humerus without setose punctures ( Fig. 45 ); suture welldefined; all striae with large, asetose punctures, irregularly spaced and of confused distribution; intervals 1–4 weakly convex, intervals 5–9 moderately convex; interval without microsculpture; 7 th strial setal pattern ( Fig. 1 ) without setose punctures in anterior ½, 2–3 setose punctures in posterior ½, setose punctures large.

Ventral surface: Mesepisternum and metepisternum with wrinkles; setose punctures absent on mesocoxa and metacoxa. All abdominal ventrites ( Fig. 2 ) lineate; ventrites 3–5 without setose punctures each side of midline; ventrite 6 setae present: ♂ and ♀ with 1–3 setae each side of midline along a bluntly rounded apical edge; ventrites foveate laterally (very small and shallow). Anterior metaventrite process a short triangle with a broad carina the entire length.

Male genitalia: Apical portion of penis lobe symmetrically rounded with a strong deflection to right of vertical axis (VV) ( Fig. 15A ), apex is a slightly flattened curve ( Fig. 45 PL), shaft of penis lobe straight (VV), shaft of penis lobe narrowed apically but gradually broadened toward base, overall length of the penis lobe slightly curved ventrally (LV) ( Fig. 16A ). 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; seta (scales) coverage of the apical plate extensive (76–100%); size of left setose flange small; size of right setose flange large. Left paramere basal lobe narrowly rectangular with a small dorsal hump, short slope to arm ( Fig. 45 LP); arm short and broad, gradually narrowed to terminus; apical tuft of very long setae; setae extended along apical ½ (just past arm junction) of ventral edge; ventral edge moderately curved. Right paramere narrowly triangular, gradually narrowed to terminus with a double row of long setae extended along apical ¾ of ventral edge ( Fig. 45 RP).

Female genitalia: Basal gonocoxite 1 short and broad apically, ventral surface smooth, internal dorso-lateral carina with 1 seta near edge of gonocoxite 2. Gonocoxite 2 short and rounded triangle, slightly reflexed along apical edge. Ramus ( Fig. 5 ) long and narrow.

Comments: Mecodema parataiko is the most geographically widespread species of the curvidens species group found in Northland.

Distribution: New Zealand, North Island, Northland, Parataiko Range, Warawara Forest, Tangihua Range, Omahuta-Puketi F.P., Mangamuka S.R., Herekino Forest and Ahipara Plateau.

Holotype: NZAC male labelled. NEW ZEALAND ND Mangamuka Gorge Wkwy 350m 351140S/1732725E 17.IX.–16.X.1999 Larivière. Larochelle / wet broadleaf forest pit traps / HOLOTYPE Mecodema parataiko n. sp. design. Seldon & Leschen 2010 [red label].

Paratypes: (see Seldon & Leschen 2011).

Material examined: 1♀, NEW ZEALAND ND, Maungataniwha Range , Mangamuka River S.R., PTs 13–21 Jan 2010 D.S. Seldon, T.R. Buckley / Kauri-broadleaf forest, pitfall traps ( NZAC) ; 1♂, 1, NEW ZEALAND ND, Herekino Forest Saddle Tk , PTs, 14–21 Jan 2010, D.S. Seldon, T.R. Buckley / 35°12.393, 173°11.487 223 m, CAR39B ( NZAC) .

Figures

FIGURE 1. Dorsal view of a Mecodema specimen showing taxonomic structures used in the species descriptions. H =head; P = pronotum; E = elytra; S = striae; I1 = interval 1; A = apex; 7S = 7 th strial setae; HSP = humerus setose puncture; HA = humeral angle; BM = basal margin; P = protibia.

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 45. Mecodema parataiko 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.