Eurhopalothrix procera

Longino (2013): A single alate queen from La Selva Biological Station in Costa Rica closely matches E. procera, based on literature descriptions and images on AntWeb. The specimen was obtained in a canopy fogging sample in October, 1994, as part of a large-scale arthropod survey project. In spite of intensive sampling for ants at this site (Longino et al., 2002), no other specimens were collected, and this single queen remains the only known specimen of E. procera from the New World. This is remarkable, because E. procera is a polytypic species found in New Guinea and multiple Pacific islands west of New Guinea (Brown and Kempf, 1960; Taylor, 1968, 1980; AntWeb, 2013), and related species also occur in this region (Taylor, 1968, 1970, 1980). Taylor (1980) describes E. procera as "Widespread in rain forest and marginal habitats; East Indies, Philippines, Melanesia, Polynesia east to the Samoan Islands, and Cape York Peninsula ..." Its occurrence on multiple oceanic islands and in marginal habitats suggests a high dispersal ability and raises the possibility that it is an adventive species in Costa Rica. Alternatively, it may be a relict lineage with a rare Neotropical representative.

Identification
Eurhopalothrix procera has the double tooth row found in Eurhopalothrix gravis and relatives. The double tooth row is visible on the La Selva queen and on the AntWeb image of a queen from the Philippines (Holotype of E. procera subdentatus [Donisthorpe, 1942], a junior synonym of E. procera). It is unknown whether other species in the procera group also have the double tooth row. Cursory examination of the three Old World species Eurhopalothrix australis, Eurhopalothrix dubia, and Eurhopalothrix omnivaga showed that these species lack the double tooth row.

The labrum of the La Selva queen is elongate, triangular, with two small lobes at the apex. The labrum is visible on the image of the E. procera subdentatus holotype, and appears similar. The La Selva queen is smaller and with narrower head than other known E. procera queens. Brown and Kempf (1960) report worker HW 0.98–1.35 and CI 106–111, with queens being the same as or slightly larger than workers. The La Selva queen has HW 0.91 and CI 95.

Key to New World Eurhopalothrix

Key to Australian Eurhopalothrix Species

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: Borneo, Indonesia, Palau, Papua New Guinea, Philippines, Samoa, Solomon Islands. Neotropical Region: Costa Rica.

Nomenclature

 *  procera. Rhopalothrix procera Emery, 1897c: 572, pl. 14, fig. 18 (w.q.) NEW GUINEA. Combination in Eurhopalothrix: Brown & Kempf, 1960: 225. Senior synonym of angulinodis, ballionii, borneensis, kokodensis, malua, manni, samoana, subdentatus and material of the unavailable name melanotica referred here: Brown & Kempf, 1960: 225.
 * ballionii. Rhopalothrix procera var. ballionii Forel, 1904d: 175 (w.) INDONESIA (Morotai I.). Junior synonym of procera: Brown & Kempf, 1960: 225.
 * borneensis. Rhopalothrix borneensis Wheeler, W.M. 1919e: 96 (q.) BORNEO. Junior synonym of procera: Brown & Kempf, 1960: 225.
 * malua. Rhopalothrix procera subsp. malua Mann, 1919: 358, figs. 36-38 (w.q.m.) SOLOMON IS. Junior synonym of procera: Brown & Kempf, 1960: 225.
 * manni. Rhopalothrix manni Menozzi, 1923b: 210, fig. 2 (w.) PHILIPPINES. Junior synonym of procera: Brown & Kempf, 1960: 225.
 * angulinodis. Rhopalothrix angulinodis Stitz, 1925: 122 (w.) PHILIPPINES (Palawan I.). Junior synonym of procera: Brown & Kempf, 1960: 225.
 * samoana. Rhopalothrix procera st. samoana Santschi, 1928a: 51, fig. 5 (w.m.) SAMOA. Junior synonym of procera: Brown & Kempf, 1960: 225.
 * kokodensis. Rhopalothrix (Rhopalothrix) kokodensis Donisthorpe, 1936e: 524 (q.m.) NEW GUINEA. Junior synonym of procera: Brown & Kempf, 1960: 225.
 * subdentatus. Rhopalothrix (Rhopalothrix) subdentatus Donisthorpe, 1942b: 67 (q.) PHILIPPINES. Junior synonym of procera: Brown & Kempf, 1960: 225.