Mecodema kokoroiho, 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 : 62-63

Mecodema kokoroiho sp. n.

Figure 34 .

Diagnosis: Distinguished from other North Island Mecodema species by: 1, vertexal groove broad and shallow with a few scattered, obsolescent punctures and rugose wrinkles laterally; 2, the pronotal foveae deep and narrow (distinctly formed by posterior sinuation); 3, intervals 1 and 7 continued to base; 4, distinctive shape of the apical portion of the penis lobe ( Fig. 34 PL).

Description: Length 27–34 mm, pronotal width 6.5–9 mm, elytral width 8–11 mm. Colour of body matte to glossy black, coxae and femur dark reddish-brown, tibiae black.

Head: Broad and flat ( Fig. 14A ). Vertex with very fine wrinkles forming an isodiametric pattern; vertexal groove well-defined, broad and shallow laterally with a few scattered obsolescent punctures and rugose wrinkles laterally; small supraorbital puncture ( Fig. 9 ) bearing 3–4 setae; 4–5 well-defined supraorbital grooves extended onto frons; frons with shallow grooves laterally, medially convex, a broad and shallow depression each side (extended to frontoclypeal area) of midline; frontoclypeal suture ( Fig. 9 ) indistinct with indistinct to small tentorial pits within a larger depression; anterior area of clypeus medially convex posterad with 3 shallow grooves; 1 clypeal puncture each side bearing 1–2 setae. Labrum lobate, anterior edge strongly emarginated 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°), strongly indentate ( Fig. 12A ); mentum setae absent. Submentum sclerite constriction broad with 6 evenly spaced setae. Stipes with 2 basal setae. Gula pits small, suture defined, gula flat and smooth. Gena with a finely wrinkled isodiametric pattern across entire area.

Prothorax: Prothoracic carina ( Fig. 11 ) narrow the entire length, crenulations absent with 8–12 setae each side, extended beyond anterior angle; posterior sinuation indistinctly carinate, angled slightly inward; pronotum broad and flat, deflected laterally, overall shape cordate ( Fig. 34 ); disc with very fine transverse wrinkles laterally; midline well-defined, anterior medial triangular impression and posterior medial diamond-shaped impression present; pronotal foveae deep and narrow (distinctly formed by posterior sinuation); anterior edge inwardly curved, posterior edge straight ( Fig. 34 ). Prosternum concave with very fine 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 evenly convex ( Fig. 6B ); basal margin slightly curved and gently sloped to base, intervals 1 and 7 continued to base; lateral carina narrow the entire length ( Fig. 34 ), extended beyond humeral angle; humerus with 3 proximate setose punctures and 1 double-spaced posterad; suture indistinctly impressed; striae with small, regularly spaced asetose punctures, indistinct near suture to more visible laterally; intervals 1–6 weakly convex, intervals 7–9 moderately convex, interval 9 truncated anterad prior to humerus; interval microsculpture present in form of fine transverse lines; 7 th strial setal pattern with 3 setose punctures in anterior ½, 5 setose punctures in posterior ½ ( Fig. 34 ), setose punctures small.

Ventral surface: Mesepisternum with obsolescent punctures and a few lines, metepisternum without microsculpture; setose punctures present on mesocoxae (2) and metacoxae (2). All abdominal ventrites ( Fig. 2 ) finely lineate; ventrites 3–5 with 1–2 setose punctures each side of midline; ventrite 6 setae present: ♂ with a pair of closely spaced setae at the junction of squared apical edge and curve anterad, ♀ with 3 setae each side, 1 proximate medially, 2 clustered together distantly from midline, apical edge obtuse rounded; ventrites foveate laterally (very shallow depressions). Anterior metaventrite process ( Fig. 2 ) a short triangle with a well-defined narrow carina the entire length.

Male genitalia: Apical portion of penis lobe asymmetrically hooked and width broad with a moderate deflection to right of vertical axis (VV) ( Fig. 15B ); ventral process a very short point at centre, apex symmetrically curved upward to form a distinctly recurved, rounded dorsal process (looks like a dolphin fin) with a brief and sharp returned curve to shaft ( Fig. 34 PL); penis lobe shaft narrow but broadened at apex and towards base; penis lobe ventral edge with a moderate curve to right (VV); 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 extensive (76–100%); size of left setose flange small; size of right setose flange very long. Left paramere basal lobe articulated at right angle, broad and short with moderate dorsal hump forming steep slope (60°) to truncated arm ( Fig. 34 LP); arm narrow and short; terminal lobe distinctly short and broad; apical tuft of sparse medium-lengthed setae, very short setae continued to medium-lengthed setae form a comb at junction of arm and basal lobe ( Fig. 34 LP); setae extended along along ½ of ventral edge; ventral edge straight. Right paramere a narrow, humped triangle with a double row of long setae along apical ¾ of ventral edge ( Fig. 34 RP).

Female genitalia: Basal gonocoxite 1 short and broad, broadened apically, branched grooves on ventral surface; internal dorso-lateral carina ( Fig. 5 ) without setae. Gonocoxite 2 ovate in shape. Ramus short and relatively broad, rounded apically.

Comments. The description of Mecodema kokoroiho is based on 46 specimens caught during three trapping events (2007, 2008, 2009), from several locations within Warawara Forest Park, northwest Northland. This species has been found along forest edge near clearings and within 50 m of streams in cut-over broadleaf forest, but no specimens have been caught in areas of Warawara Forest where kauri ( Agathis australis ) trees are dominant.

Distribution. New Zealand, North Island, Northland, Warawara Forest.

Holotype: NZAC male labelled. NEW ZEALAND ND Warawara Forest Hauturu Stream 7–21 Nov 2009 pitfall traps D.S. Seldon / HOLOTYPE Mecodema kokoroiho n. sp. design. DS Seldon, TR Buckley 2018 [red label].

Paratypes: 3, NEW ZEALAND ND Warawara Forest Hauturu Stream 16-18 Dec 2007 pitfall traps D.S. Seldon & T.R. Buckley ( NZAC) ; 13, 1♀, NEW ZEALAND ND Warawara Forest Hauturu Stream 8–13 Dec 2008 pitfall traps D.S. Seldon, T.R. Buckley & R.A.B. Leschen ( NZAC) ; 15, NEW ZEALAND ND Warawara Forest Hauturu Stream 7–21 Nov 2009 pitfall traps D.S. Seldon 35°22.131 173°17.081 ( NZAC) ; 10, NEW ZEALAND ND Warawara Forest clay bank edge 7–21 Nov 2009 pitfall traps D.S. Seldon 35°22.309 173°17.139 ( AMNZ) ; 3, NEW ZEALAND ND Warawara Forest Kauri Plateau camp 7–21 Nov 2009 pitfall traps D.S. Seldon ( MONZ) .

Etymology: The species name, kokoroiho, means ‘a beetle found with the fern root’, was provided by Te Rarawa kaumātua Joseph Cooper, Waipuna Marae, Panguru, Northland. Being Te Reo Māori, the name is to be treated as a noun.

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 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 34. Mecodema kokoroiho 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.