Mecodema kipjac, 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 : 60-62

Mecodema kipjac sp. n.

Figure 33 .

Diagnosis: Distinguished from other Mecodema species in the North Island by: 1, the small foveae situated directly behind the eye; 2, anterad pronotal foveae on the disc a distinctive shallow depression with scattered pits and short wrinkles mesad foveae; 3, distinct shape of the apical portion of the penis lobe ( Fig. 33 PL).

Description: Length 33.1 mm, pronotal width 9.4 mm, elytral width 10.8 mm. Colour of entire body dark reddish-brown, head matte black.

Head: Broad and flat ( Fig. 14A ). Vertex with very fine wrinkles forming an isodiametric pattern laterally; vertexal groove narrow and defined by punctures medially ( Fig. 33 ), punctures absent laterally; large supraorbital puncture bearing 4 setae, small foveae behind eye and below supraorbital puncture; 2–3 indistinctly impressed supraorbital grooves extended onto frons; frons with a triangular depression each side of midline surrounded by grooves, medially convex anterad frons, extended posterad clypeus; frontoclypeal suture ( Fig. 9 ) poorly defined, tentorial pits very small; anterior area of clypeus with distinctly impressed grooves in front of raised area, 1 large setose puncture each side bearing 2 setae, 2 small punctures medially bearing 1 seta each. Labrum lobate, anterior edge rounded and strongly emarginated medially with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded ( Fig. 12F ), median process very broad (especially at base), slightly angled upward (15°), distinctlyly indentate ( Fig. 12A ); mentum setae absent. Submentum sclerite constriction narrow, broadened laterally with 3 evenly spaced setae each side. Stipes with 2 basal setae. Gula pits small, suture well-defined, gula flat with rugose lines. Gena ( Fig. 8 ) with a fine isodiametric pattern across entire area.

Prothorax: Prothoracic carina narrow the entire length but broadened at anterior angle, very slightly crenulated with 8–10 setae each side ( Fig. 33 ), extended to anterior angle; posterior lateral sinuation evidently carinate, slightly angled inward; pronotum broad and flat, overall shape cordate ( Fig. 33 ); midline impressed, anterior medial triangular impression (with wings that narrowed toward anterior lateral margin) and posterior medial diamond-shaped impression present, disc with fine transverse wrinkles laterally, anterad of foveae a distinctive shallow depression, sparsely pitted and short wrinkles mesad foveae; pronotal foveae shallow and broad; anterior edge moderately inwardly curved, posterior edge relatively straight ( Fig. 33 ). Prosternum flat with deep grooves laterally; proepisternum without microsculpture. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Broad and slightly deflected laterally; humerus anteriorly convergent (elytra look narrower) ( Fig. 6A ); basal margin slighty curved and gently sloped to base, interval 1 extended to scutellum, other intervals and striae extended to margin but not abruptly so; lateral carina narrow the entire length, extended to humeral angle; humerus with 4 equally-spaced setae (right side) ( Fig. 33 ); suture impressed; striae 1–6 asetose punctures small, regularly spaced, striae 7 and 8 asetose punctures slightly increased in size ( Fig. 33 ); intervals 1–5 flat, intervals 6–8 weakly convex, interval 9 strongly convex and terminated posterad humerus; interval microsculpture absent; 7 th strial setal ( Fig. 1 ) pattern with 3 setose punctures anterior ½, 4 setose punctures posterior ½, setose punctures small.

Ventral surface: Mesepisternum with sparse punctures present; metepisternum lineate; setose punctures present on mesocoxa (1) and metacoxa (2). Abdominal ventrites 1– 6 may be finely lineate; ventrites 3–5 with 1 setose puncture each side of midline; ventrite 6 setae present: ♂ with 1 setose puncture distantly spaced each side of straight ventral edge, (no ♀ specimen available); lateral foveae absent. Anterior metaventrite process ( Fig. 2 ) a short and broad triangle with a very broad carina the entire length.

Male genitalia: Apical portion of penis lobe asymmetrically hooked with a distinct deflection to right of vertical axis (VV) ( Fig. 15A ); a short curve down from shaft forms a bluntly rounded ventral process ( Fig. 33 PL) that is pushed forward of vertical axis ( Fig. 3 ), apex with a symmetrical and slightly flattened curve dorsad forming the short and broadly rounded (hammer-like) dorsal process, hook slightly recurved to shaft ( Fig. 33 PL); penis lobe shaft with ventral edge slightly curved to right (VV), shaft of penis lobe narrow, more narrowed prior to apex ( Fig. 33 PL), broadened toward base, overall length of penis lobe 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 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 large. Left paramere basal lobe rectangular without dorsal hump, moderately angled (45°) to arm; arm narrow the entire length with terminal lobe indistinct from arm, ventral edge of arm curved apically reducing width; longer setae bunched at apex, long setae extended to junction of arm and basal lobe ( Fig. 33 LP); ventral edge of basal lobe very straight, with setae absent. Right paramere narrow and triangular (½ width of left paramere), long narrow arm with double row of long setae extended along apical ¾ of ventral edge ( Fig. 33 RP); apical ½ of arm inwardly curved across dorsad area of penis lobe.

Female genitalia: no female specimen available.

Comments: This species has been described from a single specimen collected in Kirikopuni, situated to the northwest of the Tangihua Range across the Wairoa River, and near the southeastern flanks of the Maungaru Range, between Whangarei and Dargaville.

Distribution: New Zealand, North Island, Northland, Kirikopuni.

Holotype: AMNZ male labelled. N.Kirikopuni Wairoa R. 10 Feb 1942 [hw] / C.E. Clarke Collection / HOLOTYPE Mecodema kipjac n. sp. design. DS Seldon, TR Buckley 2018 [red label] / AMNZ 84331 [green label] .

Etymology: This species epithet is an amalgamation of my (DSS) two main supporters and the sacrifices (e.g., collecting trips instead of holidays) they have made in pursuit of my doctorate, Kipling Seldon and Jaclyn Druitt.

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 3. Detail of the apical portion of aedeagus (male genitalia) with parameres removed showing taxonomic structures, vertical and horizontal planes that are referred to in the species descriptions and redescriptions: aedeagus shaft width (ASW); vertical central line (ƑCL) [dashed line, not a structure]; horizontal central line (HCL) [dashed line, not a 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 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 33. Mecodema kipjac 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.