A New Species of Tetralonia (Thygatina) from India, with Notes on the Oriental Fauna (Hymenoptera: Apidae)

Abstract A new species of the bee genus Tetralonia subgenus Thygatina is described and figured from southern India. Tetralonia (Thygatina) macroceps, new species is particularly noteworthy for macrocephaly in males, among other characters. Previously the Oriental fauna of Thygatina was thought to consist of a single described species. Aside from T. (T.) fumida (Cockerell) and the new species proposed herein, the fauna also includes T. wickwari (Bingham), erroneously placed in Eucara (as a genus), and herein recognized as a species of Thygatina, which is thereby newly transferred to the genus Tetralonia (new combination). In addition, there remains at least one additional undescribed species, but owing to confusion surrounding the association of sexes for T. fumida and T. wickwari this material is left unnamed. The need for additional collecting in southern India and Sri Lanka is stressed in order to resolve this difficulty. Lectotypes and paralectotypes are designated for T. fumida and T. wickwari.


INTRODUCTION
Thygatina is a small group of eucerine bees confined to peninsular India and Africa south of the Sahara and presently considered a sub-genus of Tetralonia (Michener, 2000). Like other Tetralonia (i.e., Eucara and Tetralonia proper), species of Thygatina are small to medium-sized bees with relatively short antennae in the males and in the females sparse Copyright E American Museum of Natural History 2006 ISSN 0003-0082 2 Deceased 10 May 2004: Prior to his untimely passing, Dr. Baker had recognized as new the species described herein and prepared line illustrations, without having the opportunity to review the description prepared by the senior author. Thus, the description and text represents the efforts of the senior author, with whom Dr. Baker had been collaborating at the time of his death. Owing to his significant intellectual contribution as well as his preparation of the drawings, Dr. Baker is retained as co-author. scopae, adapted to carrying large pollen grains. Eucara is found only in Africa, with seven species extending as far north as Burkina Faso and Ethiopia, while Tetralonia proper is principally palearctic, with one widely distributed, polytypic species [Tetralonia (Tetralonia) malvae (Rossi): southern and central Europe, Levant, east to Iran and Central Asia] and a second in northeastern Africa [T. (T.) gossypii Cockerell]. The three groups are generally quite similar; indeed, the distinctions between Eucara and Thygatina are relatively minor, particularly given that the new species discussed herein is rather Eucaralike in character (vide infra). Known pollen sources for the genus include Malvaceae for Tetralonia s. str. (genera Gossypium, Lavatera, Malva) and Eucara (genus Gossypium), as well as Convolvulaceae (genera Ipomoea, Argyreia) and Malvaceae (genus Hibiscus) for Thygatina. Species of the genus have a sparse and distinctive metatibial scopa, presumably adapted for the collection of the large pollen grains typical for these plants.
The African species of Thygatina were treated by Eardley (1989: as Tetralonia), leaving only the Indian taxa unstudied. We herein provide a brief taxonomic summary of the known species of Thygatina (table 1), with a particular emphasis on the Indian fauna, and highlight where further collecting and work needs to be undertaken. The Indian species Tetralonia wickwari Cockerell was mistakenly referred to Eucara (Brooks, 1988) but is herein returned to Thygatina. Morphological terminology follows that of Michener (2000) and Engel (2001), while the format for the description generally follows that of Eardley (1989) . 4); antennae short (scarcely as long as twice compound eye length); mesonotal pubescence pale (figs. 1, 2); terminalia as figured (figs. 8-11). Females with head broad, inner orbits divergent ventrally (fig. 14); face with exclusively white pubescence (fig. 14); pale mesonotal pubescence ( fig. 13).
Vestiture of face white; mandible with ventral brush of long, white setae ( fig. 1); vestiture of mesosoma white except off-white dorsally (i.e., white tinged with faint infuscation, although still quite pale); vestiture of legs as on dorsum of mesosoma except infuscation stronger on hind legs, particularly inner surfaces of hind leg podites; vesiture of metasoma white except infuscated on setae of seventh metasomal tergum ( fig. 8); anterior-facing surface of T1 abundantly covered with elongate, plumose, white setae; metasomal terga II-V with white, tomentose bands in basal halves, such bands weaker on third and fourth terga ( fig. 2); fifth metasomal sternum with subapical, mediolateral patches of dense black setae.
Female. As described for the male aside from usual sexual differences and with the following minor emendations: total body length 11.6 mm (11-11.8 mm); forewing length 7.6 mm (6.9-7.8 mm). Head broad [width 3.9 mm (3.7-4.0 mm), length 2.6 mm (2.6-2.7 mm)]; lower distance between inner orbits of compound eyes greater than length of compound eye, upper distance between inner orbits of compound eyes about as long as length of compound eye. Mandible about as long as compound eye, outer apical half sometimes amber colored, apex minutely notched (appearing bluntly rounded in worn specimens). Intertegular distance 3.0 mm (2.9-3.2 mm). Pygidial plate acutely rounded at apex, lateral margins gently convex and tapering in apical half to apex; surface minutely and transversely striate.
Scopal setae fuscous; white, tomentose bands of metasomal terga II-V stronger than those of male (figs. 12, 13); apical fimbriae of fifth and sixth metasomal terga fuscous except laterally white on fifth tergum; sterna with transverse apical brushes of dense, fuscous setae. T. Wcislo''. All paratypes are in the Division of Entomology, University of Kansas Natural History Museum (the specimen collected by Nathan is in the Donald and Madge Baker Collection, the remainder is in the Snow Entomological Collection).
ETYMOLOGY: The specific epithet is a reference to the enlarged head, particularly of males, in this species.
FLORAL RECORDS: Males and females of this species have been collected at flowers of Argyreia cuneata Ker-Gawl. (Convolvulaceae).
COMMENTS: The head structure of T. macroceps is quite Eucara-like in character; i.e., the head is broad and the compound eyes are diverging ventrally (figs. 3, 5). Indeed, the overall shape of the head is quite similar to T. Tetralonia macroceps can be distinguished from T. wickwari (Bingham), the only other named Oriental species known in the male sex, by the following features (those of T. wickwari mentioned, with alternates for T. macroceps in parentheses): clypeus with narrow, submarginal yellow fascia (such fascia absent in T. macroceps: fig. 3); second flagellomere less than half length of third flagellomere (second and third flagellomeres of approximately equal lengths in T. macroceps: fig. 6); head strongly transverse, except inner orbits not conspicuously divergent ventrally (inner orbits divergent in T. macroceps: figs. 3, 5); mesofemur deeply, ventrally carinate, carina abruptly, arcuately contracted basally (mesofemur without ventral carina in T. macroceps); mesotibia expanded apically, with mesotibial spur unguiform (slender and unmodified, with mesotibial spur unmodified in T. macroceps); metafemur ventrally strongly dentate basally (metafemur unmodified, without ventral dentition in T. macroceps); metatibia at apex ventrally with strong, apically-truncate, dentiform process (such a process absent in T. macroceps); metabasitarsus slender basally, strongly expanded apically (metabasitarsus slender, parallel-sided through its entire length in T. macroceps); metatarsomeres II and III elongate, weakly pubescent (metatarsomeres II and III distinctly not elongate, similar in length to metatarsomere IV, with abundant pubescence as on surrounding tarsomeres in T. macroceps).
The female differs from T. fumida (Cockerell), known only in the female sex, by the divergent compound eyes (parallel in T. fumida); the supraclypeal area with exclusively white setae (strongly intermingled with black setae in T. fumida); the vertex with white setae, a few with slight infuscation (nearly all setae black on vertex in T. fumida); the wing membrane hyaline (strongly infuscated in T. fumida); and the tomentose bands strong and wide on the second through fifth metasomal terga (tomentose bands of metasoma weak on second through fourth metasomal terga, nearly absent on fifth metasomal tergum in T. fumida). PARALECTOTYPE: A male with identical labels as that of the lectotype (here designated). The paralectotype had been crudely dissected and is much broken (the labrum, mouthparts, and anterior legs are glued on a piece of card).

DISCUSSION
There is at least one additional species in the Oriental fauna that we have chosen not to describe. The dilemma rests on the fact that there are two undescribed males in this region-one from southern India, the other from Sri Lanka-and either could be the yet unknown male for T. fumida. Tetralonia fumida is known only from females occurring in southern India and Sri Lanka (table 1). The Sri Lankan species T. wickwari, known only from males (table 1), and an undescribed male from this same island agree well with T. fumida, yet each form of male is specifically distinct. Either T. wickwari is the male and thereby a senior synonym of T. fumida (leaving the other Sri Lankan male as an undescribed species), or the undescribed male is the unrecognized mate of T. fumida. The matter is further complicated in that a third, specifically distinct male is known from the mainland in southern India. Since T. fumida is known to occur in both Sri Lanka and southern India, this third form could alternatively be the long-lost male for the species. Should this scenario prove to be true, the female of T. wickwari would remain undiscovered and the second Sri Lankan male would represent an undescribed species. Regardless, there is either a new species in southern India or in Sri Lanka. That T. wickwari and T. fumida are synonyms and that both unassociated males are new is a remote possibility. Until males and females are captured together (ideally in copula), thereby revealing which is the new species and which is the male for T. fumida, it is prudent to hesitate naming these forms. More intensified collecting in the region is required to resolve this issue.
A specimen of the potentially new southern Indian male is in the Donald and Madge Baker Collection, Division of Entomology, University of Kansas Natural History Museum. The specimen is labeled ''South India: Nilgri Hills, Cherangode, 3500 ft, xi 1950, P.S. Nathan''. A specimen of the potentially new Sri Lankan male is in the Natural History Museum, London, labeled ''Colombo, Ceylon, O.S.W. 6.08'' // ''Ceylon, O.S.W. 6.08. O.S. Wickwar. 1912-189''. The Ceylonese male is similar to the peninsular male but differs by the inner orbits of the compound eyes being conspicuously divergent, the metatarsi less elongate and slender, and metatarsomeres II and III short and conspicuously pubescent, especially apically and dorsally. Additionally, the Ceylonese male has the metabasitarsus parallel-sided, the clypeus dark, the labrum testaceous, the second flagellomere half as long as the third flagellomere, and the fifth metsasomal sternum between the lateral tufts of setae being glossy and devoid of macrosculpture.