Phaelota variabilis (Jacoby)

Prathapan, K. D. & Konstantinov, A. S., 2009, Descriptions of eight new species of Phaelota (Coleoptera: Chrysomelidae) with a new generic synonymy and a key to species of Indian subcontinent, Zootaxa 1991, pp. 1-27 : 19-22

Phaelota variabilis (Jacoby) , status restored

( Figs 70 – 75)

Thrylaea variabilis Jacoby, 1887: 99 ( Sri Lanka, lectotype, designated here, examined, BMNH). Maulik, 1926: 308–309; Ogloblin, 1930: 98 (synonymy); Scherer, 1969: 234.

Distribution. Sri Lanka.

Host plants. Unknown.

Description. Total body length 2.3 mm, width 1.7 mm. Head, pronotum, legs, all ventrites, basal six antennomeres and scutellum brown ( Figs 70 – 73). Elytron dark brown with lighter apex, epipleuron, humerus and sutural area. Distal five antennomeres black, last with lighter apex.

Frons and vertex form slightly convex line in lateral view, frons being more convex than vertex. Vertex moderately flat, sparsely punctate ( Fig. 73). Antennal callus moderately raised, nearly transverse, high near supracallinal sulcus than near supraantennal sulcus, separated from each other by short midfrontal depression hardly entering into interantennal space. Midfrontal sulcus weak. Suprafrontal sulcus absent. Frontal ridge sparsely minutely punctate. Anterofrontal ridge without vertical carina medially. Maxillary palpus with preapical palpomere slightly longer than half of apical.

Second and third antennomeres subequal; fourth to sixth each progressively but slightly decrease in length; seventh about two times thicker and longer than sixth; eighth and ninth each slightly longer and thicker than seventh; tenth slightly shorter than ninth but as thick as ninth; eleventh slightly less than two times length of tenth. Width of tenth antennomere more than half of its length ( Fig. 75).

Pronotum slightly narrower anteriorly than posteriorly. Lateral margin weakly curved ( Fig. 71). Anterolateral callosity forming obtuse denticle at pore. Disc shiny, punctation fine with scattered moderate sized punctures besides a few strong punctures in antebasal transverse impression. Antebasal transverse impression distinct on either ends, indistinct in middle. Scutellum shiny, finely granulate, wider than long, apex narrowly rounded. Elytron with well developed humeral callus, with barely perceptible depression posteriorly, maximum width at proximal 1/3, interstices moderately convex with minute punctures. Width of interstices subequal to 2 – 5 times diameter of a puncture. Epipleuron subhorizontal, not reaching apex. Metasternum about two times as long as prosternum.

Metatibia straight in lateral view, slightly curved from dorsal view, dorsally convex in proximal 2/3, rest of surface flat ( Fig. 72). Metatibial spur much shorter than claw. Proximal margin of last abdominal sternite with setose emargination in middle.

Median lobe of aedeagus gently curved in lateral view ( Fig. 74). Ventral side convex, slightly narrowed in middle, apex gently depressed and bent ventrally with a pair of oblong abruptly ending depressions preapically ( Fig. 74); dorsal opening partially covered by lamina sclerotized along middle.

Female unknown.

Type material examined. Lectotype ♂. Labels : 1) Ceylon Lewis 2) 1 st Jacoby Coll. 3) Thrylaea variabilis Jac 4) Type 19040; 5 ) Lectotype Phaelota variabilis (Jacoby) des. Prathapan and Konsantinov, 2008 ( BMNH) .

Remarks. Ogloblin (1930) synonymized Phaelota variabilis with P. flavipennis (Motschulsky) . Comparison of the syntype of P. variabilis with P. flavipennis revealed important characters that reliably separate these two species (see the key below) and we therefore recognize P. variabilis as valid. In the key this species is in the same couplet with P. flavipennis , from which it can be easily differentiated by the median lobe of the aedeagus with two abruptly ending impressions basally ( Fig. 74). In P. flavipennis the impressions end gradually ( Fig. 12).