Cotithene Voss

Franz, Nico M., 2008, Revision, phylogeny and natural history of Cotithene Vo s s (Coleoptera: Curculionidae), Zootaxa 1782, pp. 1-33 : 3-7

Cotithene Voss

Cotithene Voss 1940: 5 , type species: C. globulicollis Voss, 1940: 6 , by original designation. The name is derived from the Greek word tithene , meaning "nurse" ( Brown 1956), and feminine in gender.

Diagnosis. Cotithene has a general resemblance to other genera in the subtribe Phyllotrogina (see Franz 2006). Particularly the females may be difficult to distinguish from members of the related genus Terioltes and other cyclanth-associated taxa that are traditionally referred to as Phyllotrox Schoenherr , yet in actuality remain undescribed (see Franz 2003a). Nevertheless, Cotithene may be distinguished from all other derelomines by the following synapomorphic features: males with rostrum in lateral view submedially expanded, dorsolateral margins of rostrum carinate-expanded, ventral margin of head angulate, pronotum slightly expanded to globular, anterior margin of prosternum with row of long, anteriorly directed setae, aedeagus with separately arched rami projecting dorsally along subapical region, aedeagus with paired sclerites of internal sac explanate-triangular, vertically orientated; females lacking these modifications yet similarly fairly large (i.e., 2.7–5.9 mm) and with procoxal cavities subcontiguous to separated by about width of antennal club (i.e., not contiguous). Additional modifications of the head, prothorax and terminalia are associated with subgroups within Cotithene and provided, e.g., in the key to the species. Using the above characters, the males of Cotithene are easily distinguished from those of other genera. The females of the two relatively small species (see details below) are distinguishable from those of Terioltes by a slightly broader and less arcuate rostrum as well as an overall more robust and dorsoventrally depressed shape, and those of the five larger species from other related derelomines by their size alone, and by the unique color patterns present in some species (see key).

Redescription. Male. Length 2.8–6.1 mm, width 1.0– 2.8 mm; shape oval to elongate, l/w = 2.1–2.8, widest near humeri ( Fig. 1 ); in lateral view slightly depressed, dorsally slightly to distinctly convex (pronotum), ventrally slightly convex; color variously light yellowish-brown to reddish-brown to black (elytra); sculpture punctulate; vestiture sparse, short, fine, appressed-recurvate, aurate.

Mouthparts. Mandible ( Fig. 4 A) with 2 teeth; outer tooth longer and narrower, slightly superposed, outer margin with 2 small setae; inner tooth with narrow basal incision, inner margin rounded, explanate. Maxilla ( Fig. 4 B) with cardo arcuate, apically gradually expanded, with 2–4 small setae; stipes apically oblique, with 1 large seta; galea + lacinia + palpiger fused, with oblique suture, outer margin medially with 1 large seta and subapically with 1 small seta, inner third with densely arranged setae, inner margin with 4–6 lacinial teeth, subapically with 2 stout setae; maxillary palps 2–segmented; segment I slightly shorter than II, outer margin subapically with 1 small seta; segment II apically papillate. Labium ( Fig. 4 C) with prementum subquadrate, with 1 large seta medially along each lateral margin, apical margin irregularly undulate; median tendon of ligula with densely arranged setae; labial palps 3–segmented; segment I longer than II, outer margin medially with 1 large seta; segment II longer than 2x length of III, outer margin apically with large, triangular, acute projection extending beyond III; segment III globular, apically papillate.

Rostrum. Length 0.6–1.7 mm, shorter than pronotum, r/p = 0.5–0.9, reddish-brown, dorsally and ventrally variously slightly arcuate to angulate, expanded near middle; subparallel to apically slightly narrowed; in cross-section subrectangular; dorsally slightly impressed and/or rugulose near base, dorsolateral margins slightly carinate (cf. Voss 1940: 6, "Rüssel seitlich auf der ganzen Länge ziemlich scharf gekantet"), undulate, more prominent near antennal insertion; ventrally with 2 median sulci extending along apical half, glabrate; antennal insertion near apical third to basal 2/5; scrobe extending to eye, straight, basally gradually broadened, vaguely defined, dorsal margin acutely carinulate, position lateral throughout.

Antenna. 11–segmented, extending beyond anterior margin of pronotum (in repose), slender; scape extending to base of rostrum (nearly reaching eye), slightly shorter than funicle + club, slightly arcuate, clavate; funicle 7–segmented; segment I as long as II–IV or II–V, elongate, clavate; II–VII small, subequal in length, gradually progressing from elongate to transverse, clavate; club 3–segmented, similar in length to IV– VII of funicle, oval; segments subequal in length; I slightly separated; II+III light brown, with densely arranged, short pubescence.

Eye. Small, subcircular to elliptical (along vertical axis), protruded, distant from anterolateral margin of pronotum by nearly 0.25x its length, interocular distance slightly larger than apex of rostrum, aurate-argentate, often with obscure subcircular maculations.

Head. Small, globular, color light to dark-reddish brown; frons with more or less distinct, variously sculptured (rugulose), broad elevation, laterally and/or posteriorly with or without 1 to 3 small to fairly large, triangular projections, frontal disk setose, with sparse, short, recurvate to dense, very long, suberect, anteriorly directed, aurate setae; region adjacent to posterior margin of eye slightly impressed, thereafter carinate, with apparent short, aurate setation; head not evenly convex; ventrally angulate: with distinct, transverse impression separating anterior and posterior halves, each region subplane, glabrate.

Prothorax. Slightly to distinctly globular (in the latter case with apparent positive allometry), l/w = 1.0– 1.1; pronotum with anterior margin nearly 0.6x as wide as posterior margin, widest near posterior 2/5; in dorsal view anteriorly gradually narrowed, with or without obscure anterolateral impression, lateral margins rounded, anterior margin medially slightly emarginate; densely punctulate throughout, with dark reddishbrown punctate maculations throughout anterior 1/6 to 1/4; posterior margin bisinuate, medially slightly projected; prothorax in lateral view widely tumescent above procoxal cavities; anterolateral margin undulate, roundly projecting towards posterior margin of eye.

Mesepisternum trapezoidal. Mesepimeron pentagonal, dorsally projecting to pronotum + elytron. Metepisternum pentagonal, anteriorly abruptly broadened, posteriorly gradually narrowed, acute; sclerolepidia absent (see Lyal et al. 2006). Metepimeron triangular, extending above posterior third of metepisternum.

Thoracic ventrites. Proventrite (including prosternum and hypomera) nearly 2x as long as mesoventrite, anterior margin anteroventrally projected, medially emarginate, with row of long, anteriorly directed, aurate setae, anterior half variously impressed or tumescent to tuberculate, with densely arranged pubescence, posterior margin (hypomera) medially slightly emarginate, with row of posteriorly directed setae; procoxal cavities at posterior third of length (anterior region nearly 4x as long as posterior region), separated by about width of antennal club. Mesoventrite nearly half as long as metaventrite, transverse, slightly convex, retracted from ventral plane (inflected); mesocoxal cavities separated by about width of mesocoxa. Metaventrite transverse, medially subplane to slightly concave, laterally convex, medially sulcate throughout length, anterior margin projecting between mesocoxae, slightly emarginate, posterior margin with obtuse triangular projection near inner margin of each metacoxa; metacoxal cavities separated by distance nearly 0.6x as wide as metacoxa.

Metendosternite. Stalk shorter than furcal arms; ventral flange broader than stalk, lateral margins emarginate, dorsally gradually converging; lamina nearly 0.25x as long as median sclerotization; lateral projections apically clavate; anterior tendons inserted near base of furcal arms, converging; furcal arms straight to slightly angulate, dorsally diverging, apically gradually narrowed, bifurcate, apices acute.

Legs. Front legs slightly longer than middle legs, slender, yellowish- to reddish-brown; coxa large, conical, inner margin with 1 subapical foveola; trochanter apically expanded, oblique; femur 0.6–0.8x as long as pronotum, fairly slender, sinuate, compressed, widest near apical 2/5; tibia 0.7–1.0x as long as femur, slender, straight to sinuate, slightly compressed, apically expanded, angulate, ventrally with densely arranged vestiture in apical half, apical margin with row of 35–45 spines, with additional row of long setae, unarmed; tarsus nearly 0.6x as long as tibia; tarsites I–III dorsally with slightly darker, median stripe; I longer than II; II nearly half as long as III; III similar in length to I+II, bilobed, lobes slender, apically slightly diverging; IV nearly half as long as II; V similar in length to II+III; tarsal claws nearly 0.4x as long as V, paired, simple. Middle legs slightly shorter than hind legs; mesocoxa globular; mesotibia and metatibia lacking distinct ventral vestiture.

Scutellum. Exposed to nearly covered by elytra, small, triangular, posteriorly acute, light to dark reddishbrown.

Elytra. Elongate, l/w = 1.3–1.6, widest near humeri to anterior third, anteriorly slightly wider than posterior margin of pronotum; anterior margins bisinuate, humeri slightly projected, subrectangular; lateral margins subparallel throughout anterior third to half, gradually converging (attenuate or evenly rounded) throughout posterior two-thirds to half, apices rounded to truncate, contiguous; in lateral view dorsally evenly convex, with or without additional slightly convex elevation along anterior 1/5, lateral margins sinuate; 10–striate, striae narrower to slightly broader than intervals, I–VII shallow, VIII–X deeper, III+VI+VIII merging towards apex, IX slightly ascending along anterior third, X along lateral margin; strial punctures dark reddish-brown, subcircular to subrectangular, slightly separated; intervals reddish-brown to dark brown to black, anterior 1/5 of intervals VIII–IX + IX–X slightly elevated, vestiture short, sparse, directed posteriad, recurvate.

Wings. 1.1–1.2x longer than body, l/w = 3.2–3.3; anal lobe distinct, small; C + Sc merging near base, R basally ascending (thereafter merging), Cu, Cu1 and 2A present, 1A and 4A absent; with 1 large, elongate, apically rounded maculation in radial field and 2 large, elongate maculations in apical field, posterior one nearly 2x as long as anterior, darker one, extending to apex of wing; with 2 radial sclerites + 1 radiomedial sclerotization present; long macrosetae along basal 1/6 of posterior margin (anal lobe), short macrosetae sparse along C, dense along posterior margin, microsetae throughout surface.

Abdominal ventrites. Jointly shorter than 2x length of lateral margin of metaventrite, medially subplane, posterior edges of ventrites II, III and IV visible in posterior view; I+II fused; I longer than II; II slightly shorter than or similar in length to III+IV; V slightly shorter to slightly longer than II, posterior margin straight, medially slightly projected.

Pygidium (tergum VII). Anterior half covered by elytra, slightly longer than ventrite V; in dorsal view subcircular to trapezoidal, slightly transverse, medially subplane, posterior margin straight to rounded, distinctly plicate, medioventrally broadly and deeply emarginate; in lateral view broad, perpendicular to orientation of venter.

Terminalia. Tergum VIII 0.5–0.85x as long as spiculum gastrale, posterior margin rounded, strongly plicate, medioventrally broadly to deeply emarginate; posterior 3/5 setose, with short, arcuate, bifid or trifid setae. Sternum VIII (each sclerite) posteriorly with 4–8 large, unifid setae. Spiculum gastrale (sternum IX) slightly to distinctly shorter than aedeagus, slender, posteriorly bifurcate (Y-shaped), furcal arms slightly arcuate to sinuate or straight, gradually narrowed, acute. Tegmen 0.25–0.6x as long as aedeagus, slender, Yshaped; apodeme distinctly shorter to longer than lateral arms, with or without small anterior expansion. Aedeagus l/w = 3.0–4.5, basidorsal margin deeply triangularly emarginate, basiventral margin slightly emarginate to slightly rounded, ventrally slightly plicate, lateral margins with or without slight subapical constriction, apex variously rounded and explanate to spatulate or narrowly projected, acute, surface along apical half to two-thirds porose; in lateral view widest near middle, subapical region dorsally distinctly expanded in region corresponding to internal sclerotizations; each side with an inner, separately arched ramus projecting beyond dorsal margins along subapical region; in lateral view deflexed to slightly recurved; internal sac with densely arranged, small denticuli; subapically in region of ostium with more or less complex, paired, symmetrical, variously elongate to triangular, V-shaped, plicate sclerotizations; ostium large; aedeagal apodemes distinctly shorter to similar in length to aedeagus, slender, apically slightly angulate, expanded.

Female. Length 2.7–5.9 mm, width 1.1–2.8 mm, l/w = 2.0–2.6, widest near anterior third of elytra; lacking darker punctate maculations along anterior margin of pronotum. Rostrum 0.8–3.8 mm in length, 0.8–2.1x as long as pronotum, slightly arcuate, lacking mediodorsal expansion, apically slightly depressed; narrow to very narrow, subparallel to apically slightly expanded; in cross-section subrectangular to elliptical, dorsolateral margins evenly convex, lacking dorsal impression or rugulosity, outline contiguous with head and evenly convex or slightly depressed at base from dorsal margin of head; antennal insertion near middle; scrobe reaching eye or nearly so (in repose), narrow, straight to arcuate. Antenna with scape reaching to base of rostrum or nearly so. Eyes distant from anterolateral margin of pronotum by nearly half their length (with head in normal position), dorsally separated by about width of rostral apex. Head evenly slightly convex, lacking sculptures, elevation, projections and setation as in male; region adjacent to posterior margin of eye less impressed or projected; head ventrally evenly convex, lacking distinct transverse angulation as present in male. Prothorax less expanded and without apparent allometry, slightly convex, l/w = 0.8–1.0, pronotum with anterior margin nearly half as wide as posterior margin, widest near middle; without anterolateral impressions, lateral margins slightly rounded, anteriorly gradually converging, anterior region lacking darker punctures; in lateral view conical, dorsally and ventrally slightly convex, tumescence above procoxal cavities less distinct, without anterior ventral angulation. Prosternum with anterior margin not ventrally projected, slightly emarginate, vestiture less distinct, anterior third subplane, lacking impressions or tumescences; procoxal cavities subcontiguous to separated by about width of antennal club; metaventrite medially slightly convex; metacoxal cavities separated by nearly 3/4 length of metacoxa. Front legs with femur 0.7–1.0x as long as pronotum, slender; tibia 0.9x as long as femur. Elytra in dorsal view not attenuate-triangular, l/w = 1.3–1.6, widest near anterior third; lateral margins subparallel to slightly diverging in anterior half, gradually roundly converging in posterior half; anterior elevation indistinct. Wings 1.2–1.3x as long as body, l/w = 3.2–3.3. Abdominal ventrites jointly nearly 2x as long as lateral margin of metaventrite; ventrite V slightly longer than II, transverse, posterior margin slightly rounded, explanate. Pygidium (tergum VII) entirely covered by elytra; in lateral view narrow, parallel to orientation of anterior terga.

Terminalia. Tergum VII 0.5–0.8x as long as sternum VIII, slightly convex; posterior margin straight to slightly rounded, explanate; with short, bi- to multifid setae throughout, with or without transverse region of 50–200 yet larger setae. Tergum VIII sclerotized, 0.3–0.5x as long as sternum VIII; posterior margin slightly rounded or emarginate, explanate; with small, evenly distributed denticuli throughout, posterior half with or without small, sparsely arranged bifid setae, posteriorly with 1–3 rows of larger, simple setae. Sternum VIII narrow, straight to slightly arcuate, anterior 3/5 to 2/3 stylate, posterior 2/5 to 1/3 bifurcate, Y-shaped; furcal arms elongate, explanate, straight to slightly arcuate, subparallel to posteriorly slightly converging or diverging, widest near or beyond middle, thereafter slightly narrowed; posterior third to half with sparse, very short setae, posterior margin with 2–10 longer, simple setae. Hemisternites 0.3–0.6x as long as sternum VIII, porose throughout, density of pores increasing posteriorly, styli large, elongate, narrow, apically with 2–4 simple setae. Bursa copulatrix small, elongate, slightly shorter than sternum VIII, with common oviduct. Spermatheca C-, J- or V-shaped, wide and short, abruptly deflexed by 80–90° near apical 3/5; slightly inflected near internal edge, with or without slight subapical constriction or small subapical projection along outer margin, apex acuminate to rounded, with or without slight deflection; gland reservoir inserted near outer edge of basal margin, large, elongate.

Variation. Size variation is significant particularly in the males of certain species, where numerous sexually dimorphic features on the rostrum, head, prothorax and elytra are either indistinct in the smallest males or strongly developed in the largest males, with intermediate states present as well (e.g., Fig. 3 ). Positively allometric size relationships are evident. Color variation is primarily related to the age of individuals at the time of capture, teneral individuals being more homogeneously lightly pigmented, pale to light reddish-brown. Intraspecific variation in the male and female genital complex appears insignificant in comparison with the external differences among species.

Figures

FIGURE 1. Dorsal habitus of Cotithene, males. A, C. dicranopygia; B, C. globulicollis.

FIGURE 3. Variation of rostrum and head in males of Cotithene stratiotricha. A, small male, lateral view; B, intermediate-sized male, lateral view; C, large male, lateral view; D, large male, dorsal view.

FIGURE 4. Mouthparts of Cotithene globulicollis. A, left mandible; B, right maxilla; C, labium. Scale bars 0.1 mm. For further detail see also Franz (2006).