Mecodema manaia 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 : 69-71

Mecodema manaia Seldon & Leschen, 2011 .

Figures 12A , 15B , 16C and 37 .

Diagnosis: Distinguished from other North Island Mecodema species by having: 1, the pronotal carina with 3–4 setae along each side ( curvidens species group); 2, pronotum overall shape squared, midline poorly defined, medial impressions and microsculpture absent; 3, elytral interval 7 curved inwardly to parallel humeral angle; 4, ventrites 3 and 4 without setose punctures, ventrite 5 with 1 setose puncture each side of midline.

Description: Length 24.5–28.7 mm, pronotal width 6.5–7.7 mm, elytral width 7.8–9.2 mm. Colour of entire body matte to glossy black.

Head: Broad and convex ( Fig. 14B ). Vertex smooth; vertexal groove narrow, well-defined the entire length, curved posterad at midpoint; small supraorbital puncture bearing 3 setae; 3 moderately impressed supraorbital grooves; frons with a large and shallow depression each side of midline; frontoclypeal suture ( Fig. 9 ) well-defined, tentorial pits large; anterior area of clypeus with broad and shallow grooves, 1 setose puncture each side bearing 2 setae ( Fig. 37 ). Labrum rounded, anterior edge outwardly curved with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded ( Fig. 12F ), median process narrow and short, slightly angled upward (15°), moderately indentate ( Fig. 12B ); mentum setae present. Submentum sclerite constriction narrow with 4–6 evenly spaced setae. Stipes with 2 basal setae. Gula pits large, suture indistinct, gula flat with transverse lines present. Gena ( Fig. 8 ) with very fine lines forming an isodiametric pattern across entire area.

Prothorax: Prothoracic carina narrow the entire length, slightly crenulated with 3–4 setae each side ( Fig. 37 ), extended to anterior angle; posterior lateral sinuation indistinctly carinate, parallel; pronotum broad and laterally deflected, overall shape squared; midline poorly defined, medial impressions and microsculpture absent; pronotal foveae deep and narrow; anterior edge ( Fig. 11 ) inwardly curved, posterior edge curved, emarginated medially. Prosternum flat with fine transverse lines; proepisternum without microsculpture. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Broad and moderately deflected; humeral angle evenly convex ( Fig. 6B ); basal margin moderately curved and bevelled to base, interval 1 extended to margin; lateral carina narrow the entire length, extended to humeral angle; humerus with 2–3 setose punctures ( Fig. 37 ); suture poorly impressed; striae with small, regularly distributed, asetose punctures that slightly increased in size laterally; intervals 1–4 weakly convex, intervals 5–9 moderately convex, interval 7 curved inwardly to parallel humeral angle; interval microsculpture absent; 7 th strial setal pattern with 2 setose punctures in anterior ½, 5 setose punctures in posterior ½ ( Fig. 37 ), setose punctures large.

Ventral surface: Mesepisternum and metepisternum ( Fig. 2 ) without microsculpture; setose punctures present on mesocoxa (1) and metacoxa (1). All abdominal ventrites finely lineate laterally, ventrites 3 and 4 without setose punctures, ventrite 5 ( Fig. 2 ) with 1 setose puncture each side of midline; ventrite 6 setae present: ♂ with 2 evenly spaced setose punctures each side, most lateral pair at junction of straight apical edge and curve anterad, ♀ with 2–3 setose punctures proximate, but distantly separated on bluntly rounded apical edge; lateral foveae absent. Anterior metaventrite process ( Fig. 2 ) a bluntly rounded triangle with a well-defined, narrow carina the entire length.

Male genitalia: Apical portion of penis lobe symmetrically rounded ( Fig. 37 PL) with a distinct deflection to right of vertical axis (VV) ( Fig. 15A ); shaft of penis lobe straight and relatively broad entire (VV), overall lenght of penis lobe without curve ventrally (LV). 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 short and narrow; relative extent of setae (scales) of the apical plate sparse (1–25%); size of left setose flange small; size of right setose flange large. Left paramere basal lobe narrowly rectangular, short slope to arm; arm long and relatively broad, gradually narrowed to terminal lobe; terminal lobe indistinct from arm, apical tuft of long setae; medium-lengthed setae continued along apical ¾ of ventral edge ( Fig. 37 LP); ventral edge slightly curved. Right paramere narrowly rectangular, gradually narrowed apically with medium to long setae extended along apical ¾ ventral edge ( Fig. 37 RP).

Female genitalia: Basal gonocoxite 1 ( Fig. 5 ) long and broad, flattened apically, internal dorso-lateral carina with 2 relatively long setae, ventral surface smooth. Gonocoxite 2 bluntly rounded and triangular. Ramus short and narrow.

Comments: Mecodema manaia shares similar morphological characters with M. tenaki (Cape Reinga) and M. regulus (Three Kings Islands) , and although there is suitable forest habitat along the eastern coastline to the north, no specimens have been collected from these areas.

Distribution: New Zealand, North Island, Northland, Whangarei Head’s area.

Holotype: NZAC male labelled. NEW ZEALAND ND Whangarei Heads Mt Lion 2005 F. Brook / HOLOTYPE Mecodema manaia n. sp. design. by Seldon & Leschen 2010 [red label].

Paratypes: (see Seldon & Leschen 2011).

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 37. Mecodema manaia 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.