Mecyclothorax andersoni Liebherr, 2017

Liebherr, James K., 2017, Review of Mecyclothorax Sharp (Coleoptera: Carabidae: Moriomorphini) from Papua New Guinea, with Descriptions of Five New Species, The Coleopterists Bulletin 71 (4), pp. 679-703 : 688-691

5. Mecyclothorax andersoni Liebherr , new species

( Figs. 4 , 11–14 , 17–22 , 25 , 29 , 32 )

Diagnosis. This species is the only one from Papua New Guinea with glabrous, convexly rounded pronotal hind angles. The lateral pronotal margin is only slightly concave anterad the rounded angles. The pronotal median base is rugosely punctate, with the deepest parts of punctures irregularly joined by longitudinal depressions producing a strigose appearance. There are two dorsal elytral setae in the third interval, and one seta, the apical seta, is present at the elytral apex. The eyes are small in diameter and protuberant ( Fig. 4 ). The ocular ratio is 1.38–1.50 (n = 10), with 13–17 ommatidia present along the horizontal eye diameter. Standardized body length is 4.0– 4.4 mm.

Description. Head: Broadly convex on frons between deep, arcuately approaching frontal grooves, posterior portion of groove directed toward anterior supraorbital seta, anterior terminus a deep pit just posterad a very shallow frontoclypeal suture; eyes small, moderately convex on broadly protruding ocular lobe, ocular lobe ratio = 0.74–0.83, posterior portion of ocular lobe very obtusely meeting gena at broad, shallow groove; antennomere 3 largely glabrous with a few fine setae just basad apical setal ring; antenna robust, antennomere 9 length 2.0–2.1X maximal breadth; anterior labral margin broadly, moderately convex; mandibles robust, moderately long, distance from dorsal condyle to apex 1.7–1.8X distance from condyle to anterolateral margin of labrum; vertex flat behind eyes, not impressed; mentum tooth acute, apex narrowly rounded; ligular apex narrowly rounded, ligular setae separated by 2 setal diameters, paraglossae extended only slightly beyond ligular margin. Pronotum: Broad, constricted basally with hind angles rounded ( Fig. 4 ), MPW/BPW = 1.82–2.19 (large variation due to ambiguous assessment of hind angle position on convex curve), MPW/PL = 1.21–1.30; lateral setal position adjacent to lateral marginal depression; median base depressed relative to the convex disc, 16–18 broad shallow punctures each side, anterior juncture with disc a line of punctures, posterior margin beaded behind laterobasal depression, convex medially; median longitudinal impression foveate, broad at front of median base, fine and broadly depressed on disc; anterior transverse impression obsolete medially, anterior callosity broad and flat to smooth front margin, impression increasingly well defined in outer 1/4 of breadth inside front angle; front angles only slightly protruding, rounded; lateral marginal depression narrow throughout length, narrowly lined with microsculpture at depth, edge narrowly upraised to bead; laterobasal depression irregular, large punctures present inside hind angle; prosternum with deep, smooth anteapical furrow that extends from lateral reaches across ventral surface; prosternal process convex anterad procoxae, slightly depressed medially on ventral surface between coxae; proepimeron with anterior groove slightly irregular, about 7 punctulae along length, posterior groove smooth. Elytra: Broadly hemiovoid, foreshortened, convex with lateral intervals vertical, base broad across humeri, MEW/EL = 0.78–0.84; maximum width near midlength; parascutellar seta present; scutellum moderately broad, ratio of width at transverse groove/median length = 1.65; parascutellar striole a fine, continuous groove with 2–4 punctures; elytral basal groove broadly and distinctly recurved to broadly rounded humerus; striae 1–5 shallow though continuous, punctate on disc, punctures slightly elongate, stria 6 less continuous, its punctures smaller, stria 7 a series of small, isolated punctures; striae 2–7 reduced on apex, only the sutural stria fine and deep, stria 2 represented by short depression near apex, stria 7 present only on apex; sutural apex conjoined with sutural intervals narrowly raised each side of suture; stria 8 smooth and deeply impressed at midlength; lateral marginal depression moderately broad inside rounded humerus, narrower behind, margin upraised throughout length; subapical sinuation broadly, evenly concave front to back; lateral elytral setae 7 + 6; subapical elytral seta absent, apical seta in association with apex of stria 2 present. Mesepisternum: With 5–6 large punctures in 1–2 rows, mesosternum with 2–4 isolated punctures each side anterad mesocoxal articulations; metepisternum maximum width/lateral length = 0.79; metasternal process acute, apex extended as a parallel-sided knob, knob and lateral margins broadly convex; metathoracic wings vestigial, apex not extended beyond posterior margin of metanotum. Abdomen: Ventrites 1 and 2 separated by anteriorly sinuous suture laterally, surface of ventrite 2 only slightly depressed within convex sinuosity; suture between ventrites 2 and 3 shallow but traceable laterally; broad, shallow depressions present laterally on ventrites 3–6. Microsculpture: Reduced on head, frons glossy, vertex with shallow, transversely stretched sculpticells; pronotal disc covered with indistinct, shallow, elongate transverse mesh, sculpticell breadth 3–4X length; pronotal base with indistinct transverse sculpticells between punctures, breadth 3–4X length, laterobasal depression with transverse mesh among punctures; elytral disc with well-developed transverse mesh, sculpticell breadth 4X length, apex with indistinct transverse lines, surface of elytra subiridescent; metasternum with evident transverse mesh, sculpticell breadth 3–4X length; lateral portions of basal abdominal ventrites with swirling isodiametric and transverse sculpticells. Coloration: Head dark rufous, clypeus, labrum, and mouthparts brunneous; antennae flavobrunneous, antennomeres 4–11 with piceous cast; pronotal disc rufopiceous, lateral marginal depression narrowly translucent, rufoflavous, apex and base narrowly amber colored; elytral disc rufopiceous, sutural interval concolorous, lateral marginal depression rufoflavous, apex broadly paler, rufobrunneous; proepipleuron rufoflavous to rufobrunneous, proepisternum dark rufous; elytral epipleuron rufobrunneous dorsally, rufous ventrally; metepisternum rufous with piceous cast; abdomen rufobrunneous with piceous cast, posterior margins of ventrites 3–5 flavous, apical ventrite 6 with apical half flavous; femora rufobrunneous, tibiae rufobrunneous with piceous cast.

Male Genitalia. Male parameres with bases sclerotized and apices more membranous and flexible, the ventral (right) paramere broad basally, with the apical half translucent, membranous and flexible ( Figs. 11, 13 ), ventral margin with 15–21 setae in apical 2/3 of length, plus a pair of stouter apical setae; dorsal (left) paramere broader basally, with margins glabrous basally and variously sclerotized so that base is of varying breadth in different individuals, apex extended as a narrow, whiplike extension that is flexible ( Figs. 12, 14 ) and may be bent upon itself in situ (e.g., Fig. 18 ); antecostal margin of mediotergite IX rounded distally, broadly and irregularly sclerotized ( Figs. 19, 22 ); aedeagal median lobe robust, broad basally ( Figs. 17, 18, 20, 21 ); ostial triangle present at distal margin of ostial opening; internal sac membranous, about twice as long as broad, with a rounded, lightly sclerotized flagellar plate apically ( Figs. 17, 20 ).

There is considerable variation in the length and breadth of the median lobe apex. The apex may be: 1) very short and broad dorsoventrally ( VSB form, Fig. 17 ); 2) moderately elongate and broadly recurved apically ( MEB form, Fig. 18 ); 3) elongate and distinctly recurved, the apex slightly broader than the shaft just apicad the ostium ( EDR form, Fig. 20 ); or 4) very elongate and narrow with the apex distinctly broader than the narrow shaft apicad the ostium ( VEN form, Fig. 21 ). Given the sufficiently large paratype series, these configurations were assessed among nine dissected males, taking into account locality and elevation. Only one VSB individual ( Fig. 17 ) was observed, from Mt. Kaindi , 2,200 m elevation (sample RSA 2000-43B). That same Berlese extraction sample also included one MEB individual. Other MEB individuals were found at: 1) Mt. Kaindi , 2,300 m elevation (the holotype); and 2) Edie Creek , 2,150 m (sample RSA 2000-036AA, two individuals, Fig. 18 ). Four elongate aedeagal forms were derived from Berlese samples also taken on Mt. Kaindi , syntopically and synchronously with sample RSA 2000-43 B. These include sample RSA 2000-43A with one EDR male plus two VEN males ( Figs. 20–21 ) and sample RSA 2000-43C with one VEN male dissected. Thus, males from Edie Creek, 2,150 m elevation include the two shorter forms ( Figs. 17–18 ), and males from Mt. Kaindi, 2,200 m elevation, include both longer forms plus one of the shorter forms ( Figs. 18, 20–21 ). This pattern of variation in the aedeagal apex does not allow discrimination of aedeagal form by locality or elevation, as the forms overlap among samples representing these geographic parameters. Moreover, no external characters were found to delineate individuals with these different aedeagal configurations, and so this variation is considered to be infraspecific .

Female Reproductive Tract. Bursa copulatrix with common oviduct entering ventrobasally, and spermathecal duct entering dorsobasally ( Fig. 25 ); bursa copulatrix columnar, about twice as long as broad (compressed under microslide cover slip); spermatheca globose and larger than duct; spermathecal gland entering at base of spermathecal reservoir; basal gonocoxite 1 with 2–4 apical fringe setae ( Fig. 29 ), an apicomedial seta, and several medial setae along medial margin; apical gonocoxite 2 broad basally due to extended lateral apodeme, bearing 2 gracile lateral ensiform setae, a similarly shaped dorsal ensiform seta and 2 apical nematiform setae, those setae located in fossa and situated about 1/3 gonocoxite length from apex.

Holotype. Male with genitalia dissected and placed in polyethylene genitalia vial on pin ( BPBM): NEW GUINEA: ne / Mt. Kaindi, 2350 m / 3.vi.1970 // T. Tigner T-320 / collector #13 // Mecyclothorax / toxopei Darlington / det. G.E. Ball, 1989 // P. N. G. Mecyclothorax / revision measured / specimen 1 / J.K. Liebherr 2016 // HOLOTYPE / Mecyclothorax / andersoni / J.K. Liebherr 2017 [black-bordered red label].

Paratypes. Eighteen specimens: Papua New Guinea, Morobe Prov., 19 km NNW Wau, nr. Edie Creek, 7°24´S 146°40´E, montane forest litter, 2150 m el., 6-ii-2000, R. S. Anderson, lot RSA2000-036AA ( CUIC, 2; UASM, 2); 12 km NNW Wau, Mt. Kaindi, 7°24´S 146°41´E, elfin forest litter, 2200 m el., 10-ii-2000, R. S. Anderson, lot RSA 2000-43A ( BPBM, 3; UASM, 4); lot RSA2000-043B ( CUIC, 1; UASM, 3); lot RSA 2000-43C ( UASM, 3) .

Etymology. This species is named for Dr. Robert S. Anderson, noted weevil systematist, who collected the substantial series of paratype specimens during his field research at the Wau Ecological Institute ( Gressitt 1970).

Distribution and Habitat. This species is known only from localities at 2,150 –2,350 m elevation to the northwest of Wau, Morobe Province ( Fig. 32 ). Specimens recorded from montane forest litter and elfin forest litter by R. S. Anderson were collected via Berlese extraction of sifted litter. Thus, all specimens with known collecting circumstances were derived from terrestrial litter microhabitats in forest.

Figures

Figs. 1–4. Mecyclothorax species, dorsal habitus. 1) M. kavanaughi; 2) M. baehri; 3) M. medioconstrictus; 4) M. andersoni. Range of standardized body lengths (in mm) and setal formulae (see text) for number of supraorbital setae each side, number of pronotal setae each side, number of dorsal elytral setae each elytron, and number of setae at the apex of each elytron are indicated.

Figs. 9–16. Mecyclothorax species, parameres, anatomically dorsal margin upward, right parameres odd numbered, left parameres even numbered. 9–10) M. kavanaughi; 11–12) M. andersoni, short aedeagal form, male 02; 13–14) M. andersoni, long aedeagal form, male 06; 15–16) M. gressitti.

Figs. 17–24. Mecyclothorax andersoni: 17) Male 8, VSB form, aedeagal median lobe and parameres, internal sac everted, right view; 18) Male 2, MEB form, aedeagal median lobe and parameres, right view; 19) Male 2, mediotergite IX plus rounded antecostal apodeme, short apex form, dorsal view; 20) Male 9, EDR form, aedeagal median lobe and parameres, internal sac everted, right view; 21) Male 3, VEN form, aedeagal median lobe and parameres, right view; 22) Male 3, mediotergite IX plus rounded antecostal apodeme, long apex form, dorsal view. Mecyclothorax gressitti: 23) Male aedeagal median lobe and parameres, right view; 24) Male mediotergite IX plus rounded antecostal apodeme, dorsal view. Abbreviations are defined in Table 1.

Figs. 25–28. Mecyclothorax species, female gonocoxae, laterotergites VIII, and internal reproductive tract, ventral view. 25) M. andersoni; 26) M. brispex; 27) M. gressitti; 28) M. sedlaceki. Abbreviations are defined in Table 1; position of spermathecal duct dorsad bursa indicated by dashed lines; scale bars = 0.25 mm.

Figs. 29–31. Mecyclothorax species, female gonocoxae, right side, ventral view. 29) M. andersoni; 30) M. brispex; 31) M. gressitti. Abbreviations aredefined in Table 1; scale bars = 0.05 mm.

Fig. 32. Localities in Papua New Guinea from which Mecyclothorax spp. were collected and the particular species collected at each locality. 1 = Mt. Capella — M. baehri; 2 = Mt. Fugilil — M. brispex and M. medioconstrictus; 3 = Kubor Range — M. kubor; 4 = Mt. Wilhelm — M. sedlaceki; 5 = Finisterre Range — M. kavanaughi; 6 = Mt. Missim — M. gressitti; 7 = Mt. Kaindi, Edie Creek and Bulldog Road — M. andersoni, M. cuccodoroi, and M. loebli; 8 = Mt. Amungwiwa—M. amingwiwae.