Camponotus tol, Ronald M. Clouse, Benjamin D. Blanchard, Rebecca Gibson, Ward C. Wheeler & Milan Janda, 2016

Ronald M. Clouse, Benjamin D. Blanchard, Rebecca Gibson, Ward C. Wheeler & Milan Janda, 2016, Taxonomic updates for some confusing Micronesian species of Camponotus (Hymenoptera: Formicidae: Formicinae), Myrmecological News 23, pp. 139-152 : 149-151

Camponotus tol sp.n. GIBSON& CLOUSE

( Figs. 30 ­ 35 )

Type material: Holotype major worker. Federated States of Micronesia: Chuuk, Tol Island at 120 m (7o 19' 27.3" N, 151o 36' 50.6" E), leg. R. Clouse, P. Sharma, and Techuo family. Paratypes, (3 major workers, 9 minor workers), same collection data as holotype. Twelve additional minors stored in 95% EtOH, as well as two minors each with one leg removed and used for DNA extraction, also same collection data as holotype. All specimens are deposited in the Museum of Comparative Zoology, Harvard University, Massachusetts, USA.

Description of holotype major worker ( Figs. 30 ­ 32 ): EL 0.48, EW 0.30, FCL 1.05, HL 2.05, HW 1.84, ML 2.51, MTL 1.54, PH 0.54, PL 0.60, SL 1.77; CI 90, SI 96.

Mandible outer margin gently curved to an apex of about 75 degrees, the masticatory margin straight in front view. Mandibles tightly closed, masticatory margin with five visible teeth that gradually diminish in size from apex. Clypeus continuing anteriorly past mandibular insertions a distance slightly less than length of apical tooth, then straight across. Posterior clypeus curved anteriorly forming bilobed appearance, antennal insertions separated from clypeus by a distance almost equal to the distance from nearest clypeal margin to clypeal midpoint. Head slightly longer than wide. Vertex weakly concave. In frontal view eyes located halfway between posterior clypeal margin and vertex; inner margins halfway between frontal lobes and sides of head; eyes not extending past lateral edge. Antennae 12­segmented. Antennal scape length extending past the vertex by a distance of 2 ­ 3 times the width of the scape at the apex. Mesosoma in profile gently sloping from anterior pronotum to dorsal propodeum, with moderate propodeal declivity.

Color: Distinct bicoloration: head mostly glossy brown, mesosoma uniform light yellow­brown, gaster glossy brown. Gradual lightening from vertex down to mandibles. Vertex to posterior clypeus same glossy brown as gaster. Black outlining along frontal carina. Anterior clypeus to mandibular insertions light yellow­brown. Mandibles lighter brown than vertex down to posterior clypeus. Teeth of mandibles, scrobes, sutures, and joints on the head darker than surrounding cuticle. Each gastral tergite with hyaline margin along posterior fifth.

Pilosity: Layer of short, recumbent, light hairs all over head. Long, yellow, standing hairs numerous on front, back, and sides of head. In frontal view, area between eyes and frontal carina with two rows of long, standing hairs extending from vertex to mid­clypeus. Row of long hairs extending across anterior clypeal edge. From dorsal view, mesosoma with two side­by­side groups of standing hairs on pronotum, four long hairs with some small hairs per group; one group of standing hairs on mesonotum, with three long hairs and some small hairs; two groups of standing hairs clustered on propodeum, with three long hairs per group; layer of short recumbent hairs all over each appendage, decreasing in length from trochanter to tarsus. Propleuron standing hairs indistinct but present. Each gastral tergite with 20 to 30 long, yellow, standing hairs encircling tergite immediately before hyaline margin along posterior edge; 10 to 20 longer standing hairs encircling tergite halfway between hyaline margin and posterior edge of previous tergite. Standing hairs on hind femur indistinct but present.

Sculpturing: Head and gaster surface glossy; genae weakly punctured. Mesosoma surface smooth and shiny, although not glossy.

Description of paratypes: Majors closely resembling holotype except vertex and mandibles more reddish­brown; overall slightly larger (ML 2.6 ­ 2.75 and HW 1.88 ­ 1.95); CI same (90) but SI smaller (87 ­ 92), indicating consistency in head shape and scape absolute length in larger specimens. Minors closely resembling majors in coloration and pilosity. Slightly smaller than majors (ML 2.00 ­ 2.25) and with significantly narrower heads and longer, more variable scapes (CI 76 ­ 80, SI 157 ­ 172). Scapes extending beyond vertex by a range of 25% ­ 50% of total scape length. Posterior clypeus lighter brown than holotype. Eyes extending past lateral outline of head. One minor with open mandibles has six visible teeth on masticatory margin that gradually diminish in size from the apex. Measurements of minor collected with holotype and pictured in Figures 33 ­ 35: EL 0.45, EW 0.33, FCL 0.82, HL 1.34, HW 1.05, ML 2.08, MTL 1.31, PH 0.45, PL 0.45, SL 1.73; CI 78, SI 165.

Differential diagnosis: The only specimens from Chuuk that might be mistaken for Camponotus tol sp.n. are very dark, small C. micronesicus sp.n., but C. tol sp.n. has hairs on the propleuron and hind femur, and C. micronesicus sp.n. does not. Among other similar species in Micronesia, C. tol sp.n. is not as starkly bicolorous as C. eperiamorum, and it is approximately 75% the overall size of C. kubaryi stat. rev.

Habitat: This species was collected from low­elevation, mixed agroforest (120 m a.s.l.) on Tol Island in Chuuk Lagoon. This island is the largest in the region, and reaches a maximum elevation of 439 m, but it shows evidence of agroforesty and agro­native mixed forest at all elevations. Specimens were collected from one colony and appeared to be less abundant on the island than Camponotus micronesicus sp.n.

Etymology: The specific epithet is a noun in apposition to the genus that refers to the type locality, Tol Island (pronounced " tōl ," as in the common word "toll"). Tol is the largest island inside the main atoll and island group of Chuuk State in the Federated States of Micronesia. The island is sometimes written as "Ton," as the phonemes "l" and "n" are not distinct in Chuukese.

Comments: Camponotus tol is part of a larger clade in the molecular phylogeny (Clade IV; Fig. 2) that includes C. chloroticus , C. kubaryi stat. rev., an undescribed species collected in Papua New Guinea and Indonesia, and an endemic species found on the nearby Micronesian island of Pohnpei, C. eperiamorum ( CLOUSE 2007b, CLOUSE & al. 2015). These species are all larger than C. tol , and they are also distinguished by their coloration: C. chloroticus and the unnamed species are lighter, C. kubaryi stat. rev. is darker, and C. eperiamorum contrasts more in shade among the mesosoma, head, and gaster. All of these species have the distinctive hairs on the propleuron and hind femur, but only C. tol sp.n. has such a distinctive double row of long hairs down the front of the head. Overall, C. tol sp.n. is distinct as a dusky, small, member of the Camponotus maculatus ­like species in the Pacific.

Figures

Figs. 30 ­ 35: Holotype of Camponotus tol sp. n. in frontal (30), dorsal (31), and lateral (32) views, and minor paratype from the same collection in frontal (33), dorsal (34), and lateral (35) views.