Camponotus eperiamorum

Camponotus eperiamorum appears to be a native Pohnpeian species from its habitat of high- to mid-elevation native forest.

Identification
Among species in Micronesia, Camponotus eperiamorum is most similar to Camponotus chloroticus Emery 1897, and it is thus a member of the difficult maculatus-group in the Pacific. (Camponotus maculatus was originally described by Fabricius in 1782, but see Wilson and Taylor [1967] and Clouse [in press] for more history.) Morphologically, the only difference I can find between eperiamorum and chloroticus is the dearth of long hairs on the sides of the head in eperiamorum. The coloration, however, is quite distinct and makes eperiamorum easy to identify in the field. Another close relative of chloroticus in the Pacific is Camponotus navigator (Wilson & Taylor 1967) in Polynesia. However, navigator differs from chloroticus (and thus, generally, eperiamorum) in several small but distinct morphological features, and its coloration (overall reddish to blackish brown) is very different from both chloroticus and eperiamorum. The bicoloration of eperiamorum resembles some forms in the C. maculatus group, especially Camponotus arrogans (Smith 1858). However, eperiamorum is unique in having an extremely light yellow mesosoma and displaying remarkable consistency in its coloration among various collections. Camponotus arrogans is more reddish, and its head is uniform in coloration, different from eperiamorum, which lacks red or orange and has a light clypeus and vertex. Moreover, other forms, including arrogans, have significant pilosity on the sides of the head, unlike eperiamorum, and they often have light markings on the gaster, absent in eperiamorum. (Clouse 2007)

Distribution based on Regional Taxon Lists
Indo-Australian Region: Micronesia (Federated States of).

Biology
Clouse (2007b) states the species is found in mid- to high-elevation forest and provides the following specimen label details: Holotype: FSM Pohnpei: Pohnpei I.: Mt. Nankep (1700-2000 ft., forest plants, Tw 10-VIII-1946 NMNH) Paratypes examined (37): Pohnpei I.: Mt. Nankep (1700-2000 ft., forest plants, Tw 10-VIII-1946 NMNH). Paratypes: FSM Pohnpei: Pohnpei I. (Awak: 4 queens and 1 male at light at residence; Ok; 9-VI-96); (Kitti: on dead fern branch in high elevation sakau clearing; Cs; 24-III-2000); (on road to Lehnpeinpohn Waterfall: under dead leaves on ivory nut tree; Ok&Cs; 26-XI-95); (upland forest camp near river at 300 m carrying food up tree; Cs; 5-III-95); (along river above Mahnd: large nest inside dead ivory nut branch at 200 m; Cs; 29-X-94); (0.5 mile up river from Mahnd: large nest in dead tree fern branch leaning on ivory nut tree; Cs; 29-X-95); (Malen Pahnpe above Keprohi Falls: on ivory nut along river at 350 m; Cs; 9-VII-94); (to Mt. Nahnalaud, upland forest camp near river at elevation 300m, carrying food up tree; Clouse; 5-III-1995); (to Mt. Nahnalaud from Kitti: walking on dead log at 300 m; Cs; 8-IX-95). Other specimens examined (3): FSM Pohnpei: Pohnpei I.: Mt. Nankep ([specimens on monocot midribs, possibly elephant grass, Pennisetum purpureum Schumach; clenching it with mandibles, covered with dried hyphae, large (max: 2.5 cm) fruiting body coming out of neck behind head] 1800 ft., Tw 13-VIII-46 NMNH)

The phylogeography of a group of Pacific Island Camponotus species, which included a number of species groups, was broadly examined by Clouse et al. (2015). They found Camponotus eperiamorum  is a member of a clade (Clade IV) that tenuously appears to have originated in the Australian wet tropics but has undoubtedly spread and speciated across the Pacific Islands.

Nomenclature

 *  eperiamorum. Camponotus eperiamorum Clouse, 2007a: 3, pl. 1A-C (w.q.m.) MICRONESIA (Pohnpei I.). [Also described as new by Clouse, 2007b: 202, 213.]

Worker
HOLOTYPE: TL 5.60, HL 2.15, HW 1.70, CI 79, SL 2.00, SI 118, PW 1.15, ML 0.95. Mandible outer margin gently curved to an apex of about 75 degrees, the masticatory margin straight in front view, leading to an angle of 100 degrees and a basal margin about half the length of the masticatory margin. Masticatory margin with six teeth, which gradually diminish in size from the apex (the basal tooth in some specimens broad or with a slight double point). Diastema between basal tooth and angle equal to half the width of basal tooth. Clypeus continuing anteriorly past mandibular insertions a distance slightly less than length of apical tooth, then straight across. Median clypeus curved away from vertex, antennal insertions separated from clypeus by a distance slightly more than distance from nearest clypeal margin to clypeal midpoint. Head longer than wide. In frontal view, eyes located vertically halfway between posterior clypeus and vertex; horizontally, inner margins halfway between frontal lobes and sides of the head, their width reaching halfway to the lateral edge of the head in larger workers and all the way in smaller ones. Antennae 12-segmented. Scape extending beyond the vertex by 2/5 its length. Mesosoma in profile gently sloping from anterior pronotum to dorsal propodeum, with moderate propodeal declivity. Petiolar node moderate height, anterior face half the height of posterior face and parallel. Color: Mesosoma yellow, gaster glossy black, head mostly deep orange-brown. Each gastral tergite with clear strip along posterior fifth. Head abruptly becomes same color as dorsal pronotum at vertex; border separating the coloration of vertex from remainder of the head located from the mid-vertex by a distance about as wide as width of the scape, dropping down to level of the eyes laterally. Mandibles darker than head and contrasting with clypeus. Clypeus similar in color to vertex, especially toward mandibles. Teeth of the mandibles, scrobes, sutures, and joints on the head darker than surrounding cuticle. Pilosity: On head, frontal area lateral to the eyes lacking long, standing hairs; with layer of small, recumbent, light hairs all over head; long, standing hairs numerous on front and back, frontal ones starting at clypeus and continuing to vertex, becoming less numerous but longer. Mesosoma with three pairs of long, standing hairs clustered on pronotum, two pairs clustered on mesonotum, and ten stout hairs of various lengths scattered on the propodeum. Each gastral tergite with 6–9 rather evenly spaced, short, standing hairs immediately before clear strip along posterior edge. Just after end of each tergite a row of four longer hairs on next tergite. Sculpturing: Surface smooth and shining, although not glossy.

PARATYPES: TL 5.10–6.50, HL 1.55–2.55, HW 1.05–2.30, CI 68–90, SL 1.95–2.20, SI 88–200, PW 0.85–1.30, ML 0.60–1.00. As in the holotype except head approaching square in larger workers, scape extending beyond the vertex by a range of 1/2 to 1/6 scape length in smaller to larger workers, some workers darker but retaining same contrast between body parts, area lacking long hairs lateral to the eyes extending around to the lateral back of head in smaller workers.

Queen
PARATYPES: TL 8.50–9.30, HL 2.20–2.40, HW 2.05–2.15, CI 88–93, SL 2.00–2.20, SI 95-107, PW 1.85–2.10, ML 0.90–1.10. Similar to workers except for larger mesosoma and sclerites associated with wings. Also, eyes larger and located more laterally than in major workers, their profile meeting the sides of the head in frontal view. Heads more square than those of largest workers. Mesosoma large, three times wider than workers and swollen between first and middle coxae. Metanotal tergite dark brown to black, contrasting sharply with yellow-orange mesosoma.

Male
PARATYPE: TL 6.00, HL 1.10, HW 1.20, CI 109, SL 1.40, SI 117, PW 1.45, ML 0.45. Mandible edentate, curving to a point at the apex, angle rounded, basal margin twice length of masticatory margin. Posterior clypeus bilobed, curving down from each side to a point medially. Frontal lobes reduced, interrupted by torulus. Compound eyes large, ocelli large and elevated. Antennae 13-segmented. Mesosoma large, pronotum and mesosternum swollen. Petiolar node short, anterior and posterior faces not distinctly parallel. Coloration of mandibles, clypeus, and between the antennal insertions light orange to yellow; rest of head dark orange ranging to near black between the ocelli. Metanotal tergite dark brown, as with female.

Type Material
Type locality: Pohnpei Island, Pohnpei State, Federated States of Micronesia, in mid-elevation forest.

Type series: Holotype worker and 2 paratype workers: FSM Pohnpei: Pohnpei I., Mt. Nankep [“Mt. Delennankap” on label] (1700–2000 ft., forest plants, Townes, 10-VIII-1946, NMNH). Other paratypes (85 workers, 4 queens, 1 male): FSM Pohnpei: Pohnpei I., Kitti (on dead fern branch in high-elevation sakau clearing, Clouse, 24-III-2000), Lehnpeinpohn Waterfall (on road to falls, under dead leaves on ivory nut tree, Okihiro and Clouse, 26-XI-1995), Mahnd (along river above village, elevation 200 m, large nest inside dead ivory nut branch, Clouse, 29-X-1994), Mahnd (0.5 mile up river from village, large nest in dead tree fern branch leaning on ivory nut tree, Clouse, 29-X-1995), Malen Pahnpe (above Keprohi Falls at elevation 350 m, on ivory nut along river, Clouse, 9-VII-1994), to Mt. Nahnalaud (upland forest camp near river at elevation 300 m, carrying food up tree, Clouse, 5-III-1995), to Mt. Nahnalaud from Kitti (walking on dead log at elevation 300 m, Clouse, 8-IX-1995), Mt. Nankep (“1660,” forest plants, Townes, 8-II-1946, NMNH), Awak (alates at light at residence, Okihiro, 9-VI-1996)

Etymology
This species is named in honor of the Eperiam family of Einpein Village in Kitti Municipality on Pohnpei Island. Emensio Eperiam has had a long career in environmental protection, historical preservation, and tourism on Pohnpei. His much-loved, late wife, Mercedes, and their family demonstrated extreme hospitality and generosity to those of us who wanted to hike to the interior. His sons Abram, Casandro, and Paulo guided me to remote areas and kept me from becoming lost while I collected.

References based on Global Ant Biodiversity Informatics

 * Clouse R. M. 2007. New ants (Hymenoptera: Formicidae) from Micronesia. Zootaxa 1475: 1-19.
 * Clouse R. M. 2007. The ants of Micronesia (Hymenoptera: Formicidae). Micronesica 39: 171-295
 * Clouse, R.M. 2007. The ants of Micronesia (Hymenoptera: Formicidae), Micronesica 39(2): 171-295.
 * Clouse, Ronald M. 2007. New Ants (Hymenoptera: Formicidae) from Micronesia. Zootaxa. 1475:1-19.