Larinus capsulatus, Gültekin, Levent, 2008

Gültekin, Levent, 2008, Taxonomic review of the stem-inhabiting trehala-constructing Larinus Dejean, 1821 (Coleoptera: Curculionidae): New species, systematics and ecology, Zootaxa 1714, pp. 1-18 : 5-9

Larinus capsulatus sp. n. ( Figs. 1 , 8, 9, 11, 12 )

Description. Body length 9.7–13.0 mm. Black ( Fig. 1 ); apical margin of pronotum and basal 2/3 of antennal scape brownish black. Head with short bifid white scales on ventral surface and around latero-ventral margin of eyes, dorsal margin of eye with short narrow semi-erect hair-like scales. Dorsal surface clothed with similar but slightly longer scales. Pronotum with white spots, whitish scales concentrating pronotal sides, and constitute three narrow lines on the apical half. Ocular lobes bearing moderately long brownish white setae. Elytra with small white patches formed by irregularly scattered scales concentrated at base of interval 2, intervals 3 to 5, in the middle of intervals 8 to 10, and in apical part of intervals 2 to 4. Underside more or less densely clothed with whitish hair-like scales, apical margin of ventrites 2 to 4 bearing long tufts of hair-like scales. Outer apical margin of last visible ventrite bearing dense semi-erect whitish setae.

Male. Rostrum 2.30 times as long as wide, 0.72 times as long as pronotum, sub-cylindrical; rostrum weakly constricted before eyes in dorsal view, weakly narrowing in the middle, sides between eyes and antennal scrobe straight. Apical part of rostrum 1.30 times as wide as fore femur. Ventral margin of antennal scrobes clearly visible dorsally. Surface of rostrum shining, with double, coarse and fine punctation, finely wrinkled between punctures. Dorsum in basal half with two deep, more or less triangular foveae narrowing and becoming shallower toward antennal insertion. Narrow equilateral-triangular convex area between them beginning from frontal fovea and gradually widening toward apical half of rostrum.

Antennae inserted at 0.40 length of rostrum from apex. Funicle shorter than rostrum, moderately widening apically. First segment 1.64 times as long as second, 1.21 times as long as wide; second 0.88 times as long as wide, other segments gradually becoming more transverse. Club elongate, ovate, acuminate at apex. Eyes flat, transverse, with dorsal part wider than ventral one. Frons with small round, moderately deep fovea.

Pronotum 1.22 times as wide as long, widest in basal part, angularly narrowing apically, sharply constricted in apical fifth. Anterior margin slightly projecting over head. Base deeply bisinuate, prescutellar area V-shaped, with short median carina, and distinctly projecting toward scutellum. Ocular lobes moderately developed; apical margin of prothorax evenly curving ventrally, deeply emarginated below ocular lobes. Disc moderately convex, with coarse irregular punctation, shining and bearing a fine secondary punctation between larger punctures.

Elytra 1.49 times as long as wide, in greatest width 1.30 times as wide as pronotum, subparallel-sided in basal quarter, moderately narrowing toward apex. Base of each elytron projecting anteriorly, more strongly so in area of intervals 2 to 4, and weakly raised. Intervals of 3 and 5 at base twice as wide as intervals 2 and 4. Striae 1 and 2 deeply furrowed in basal quarter, converging toward elytral suture; striae 3 to 5 moderately deep, weakly curved toward suture, 6 and 7 very shallow. Striae 1 and 2 formed on disc by fused elongate punctures, thinning toward apex but remain complete; other striae moderately wide, formed by separate punctures. Striae 9 and 10 with enlarged punctures below apical prominences. Intervals of elytra subtly punctate and finely transversely wrinkled. Disc strongly convex and shining; sutural angles moderately divergent.

Fore femur 1.22 times as long as rostrum, 1.23 times as wide as middle one; middle and hind femora weakly swollen medially. Tibiae medium-long, fore tibia moderately curved outward medially, middle and hind tibiae straight. Fore unci larger than middle ones; uncus on hind tibia 2/3 as large as that on middle tibia. Fore tibia weakly widening apically, with inner surface deeply emarginate medially, bearing small blunt denticles except for basal sixth; two denticles closest to uncus being largest and longest. Apical comb of fore tibia hanging over base of uncus, with short, dense, partly connate basal spines. Middle tibia 0.78 times as long as fore tibia, with inner margin slightly emarginated medially and bearing very small blunt denticles; spines in apical comb twice as long as those on fore tibia. Inner margin of hind tibia weakly emarginated. Tarsal segment 1 triangular, slightly longer than wide; segment 2 moderately transverse, slightly widening apically. Fore tarsus wider than middle and hind ones. Onychium moderately widening apically, projecting from lobes of segment 3 by about 2/3 of its length. Claws connate, weakly diverging, with parallel outer margins.

Ventrite III with moderately deep median depression, ventrite IV weakly depressed. Ventrite V with posterior margin wide, semi-circular.

Aedeagus in dorsal view narrowing from base to apex, constricted before middle ( Fig. 8 ), then moderately swollen, mesophallus triangularly narrowing to apex, tip weakly blunted.

Female. Females have rostrum 2.85 times as long as wide at base, 0.78 times as long as pronotum, moderately narrowing from eyes toward antennal insertion, apical part of rostrum 1.26 times as wide as fore femur. In lateral view, apical part of rostrum very weakly curved. Two dorsal foveae deeper and longer than in male, densely clothed with short hairs, continuing apically as narrow and shallow depressions, slightly widened and depressed before apex. Antennal scrobe still visible near to apex. Dorsal margins of eyes with short bifid hairlike scales.

Antennae inserted near middle of rostrum. Frons with median fovea wider than in male. Vertex with short, narrow white stripe longer than in male. Antennal club more acuminate.

Pronotum 1.32 times as wide as long; anterior margin more projecting over head than in male; punctures on disc slightly more uniform, coarse and rounded.

Elytra 1.29 times as wide as pronotum, 1.48 times as long as wide. Intervals 2 to 5 moderately raised. Striae 1 and 2 very shallow in basal half. Punctures on underside of elytra rounded, separate, each with a point in the centre.

Fore femur 1.26 times as wide as middle one. Unci on tibiae slightly longer and stronger than in male. Uncus on fore tibia wide; long and sharp subuncus situated near base of uncus and concealed by tufts of long coarse setae; denticles on inner margin of tibia longer and broader than in male.

Ventrites as in male except that central area of ventrite III very shallowly depressed. Tergite VIII wide, 1.88 times as wide as long, semi-circular in form, its sides rounded; apical half more heavily sclerotized than basal half, sclerotized area with dense, short semi-erect hair-like setae ( Fig. 9 ). Sternite VIII trapeziform ( Fig. 12 ), apical margin bearing dense, semi-erect, short hair-like setae. Spermatheca with moderately blunt apex ( Fig. 11 ).

Diagnosis. The new species is closely related to Larinus rudicollis and Larinus inaequalicollis Capiomont, 1874 . L. capsulatus sp. n. is distinguished from L. rudicollis by a shorter and thicker rostrum, a medially weakly swollen aedeagus ( Fig. 7 ) without a very sharp apex, a wide semicircular tergite VIII ( Fig. 9 ), a wide trapeziform sternite VIII ( Fig. 12 ), a blunt apex of the spermatheca ( Fig. 11 ), and rounded separate punctures on the underside of the elytra, each with one point in the center. The pattern of pubescence on the upper side of L. capsulatus more resembles that of L. inaequalicollis , but the female rostrum of the latter species is distinctly longer and the size is larger. L. vulpes (Olivier, 1807) differs from the new species by its longer rostrum and yellowish-white vestiture of dense pubescence covering a wider area. The biology of L. vulpes and L. inaequalicollis is similar to that of many other Larinus which develop in flowerheads, in contrast with that of the new species building a capsule [trehala] on plant stems. Larinus capsulatus and L. inaequalicollis share the same host plant Echinops orientalis in northeastern Turkey.

Etymology. The name of the new species refers to the larval habit of making external capsules on the plant stems.

Type material. Holotype male. Northeastern Turkey, Kars Province: 21 km E of Horasan, 40° 06' 371" N 42° 24' 417" E, 1500 m, 2.VI.1999; leg. LG. Paratypes (24 males, 33 females): Northeastern Turkey, Kars Province: 21 km E of Horasan, 1500 m, 11.VI.1998; 4 males, 4 females, leg. LG; 15.VII.1998; 1 female, leg. LG; 2.VI.1999; 10 males, 11 females, leg. LG; 2.VIII.2001; 1 male, 1 female (reared), leg. LG; 1.VI.2002; 1 male, 1 female, leg. LG; 21.IX.2002; 1 female, leg. LG; 22.VII.2003; 1 female, leg. LG; 25.IX.2003; 1 female (reared), leg. LG; 22.VI.2007; 4 male, 7 female, leg. LG; 11 km W of Karakurt, 14.VII.1999; 1 male, leg. LG; Erzurum Province: 21 km SE of Horasan, along the Eleşkirt road, 1850 m, 3.VIII.2002; 1 male, 1 female, leg. LG; 11.VI.2002; 1 male, 3 females, leg. LG; Aras Valley, 16 km E of Horasan, 40°06'363" N 42°22'386" E, 1521 m, 1.VIII.2007; 2 males, 1 females (reared), leg. L.G. Holotype and 23 paratypes deposited in EMET; 8 paratypes in ZIN; two paratypes in the following institutions or collections: EC, SMTD, EMIT, HNHM, LEMT, MCZR, MNHN, MNCN, NHM, NHMD, NHRS, RBINS, USMN.

Figures

FIGURES 1 – 4. Dorsal habitas of trehala-building Larinus species. 1, Larinus capsulatus sp. n., male, holotype; 2, L. rudicollis, lectotype; 3, L. hedenborgi, lectotype; 4, L. nidificans, male.

FIGURES 5 – 14. 5 – 8. Dorsal aspect of aedeagus. 5, Larinus nidificans; 6, L. hedenborgi; 7, L. rudicollis; 8, L. capsulatus sp. n. 9 – 14. Female genitalia; 9, tergite VIII of L. capsulatus; 10, tergite VIII of L. rudicollis; 11, spermatheca of L. capsulatus; 12, sternite VIII of L. capsulatus; 13, sternite VIII of L. rudicollis; 14, spermatheca of L. rudicollis.