Hospitalitermes nigriantennalis Syaukani & Thompson

Syaukani, Syaukani, Thompson, Graham J., Zettel, Herbert & Pribadi, Teguh, 2016, A new species of open-air processional column termite, Hospitalitermesnigriantennalis sp. n. (Termitidae), from Borneo, ZooKeys 554, pp. 27-36 : 28-31

Taxon classification Animalia Isoptera Termitidae

Hospitalitermes nigriantennalis Syaukani & Thompson sp. n. Figs 1-3, 4-5, 6-13, 14, 15

Description.

Imago. Unknown.

Soldier (Figs 1-5). Head capsule pale brown to orange with yellowish vertex and dark brown nasus; nasus paler in basal part and darker in apical part; antenna uniformly blackish, contrasting with head capsule. Pronotum in dorsal view as darker than head capsule. Abdominal tergites are gold orange to pale brown. Coxae are blackish brown; femora and tibiae pale to dark brown.

Head capsule in dorsal view strongly constricted behind antennal sockets, with anterior part excluding nasus much smaller than posterior part in size; median portion of its posterior margin nearly straight with a minute indentation in the middle; dorsal outline (including nasus) in profile weakly concave, while posterior part of head capsule fairly developed. Nasus in dorsal view more than half as long as receiving head capsule, basal part much wider than tip. Antenna with 14 segments; third segment longer than fourth, while fourth and fifth segment are nearly equal, 6 th– 14th gradually decreasing in length. Pronotum in dorsal view with anterior margin moderately indented in middle and posterior margin roundly convex.

Worker (Figs 6-13). Dimorphic. Largest workers. Head capsule dark brown to black; epicranial suture pale brown; fontanel brown to dark brown; labrum pale brown to dark brown; clypeus blackish brown to black; anteclypeus dark brown; antenna dark brown to blackish. Antenna consisting of 15 segments; third segment longer than fourth, while the fourth segment is slightly shorter than fifth, 6 th– 15th gradually increasing in length. Left mandible: apical tooth clearly shorter than first marginal tooth; anterior edge of first marginal tooth distinctly longer than posterior edge; second marginal tooth absent, incorporated into cutting edge between first and third marginal teeth; third marginal tooth smaller than first marginal tooth, weakly protruding from cutting edge and separated from molar prominence by a distinct gap; fourth marginal tooth retracted, completely hidden behind molar prominence. Right mandible: first marginal tooth with anterior edge down-curved; second marginal tooth weakly recognized and separated from much larger first marginal tooth; posterior edge of second marginal tooth straight; outline of molar plate weakly visible; cockroach notch of molar plate absent.

Comparisons.

Hospitalitermes nigriantennalis sp. n. is separated from the other species from Indo-Malayan and Austro-Malayan sub-regions by its peculiar coloration in the soldier. Specifically, Hospitalitermes nigriantennalis has prominent black antennae and palps that contrast with the pale head capsule. In other species, the head capsule is uniformly dark and does not contrast with the dark antennae. Further, by morphology Hospitalitermes nigriantennalis can be distinguished from other regional congeners Hospitalitermes rufus , Hospitalitermes hospitalis , Hospitalitermes medioflavus , Hospitalitermes moluccanus Ahmad, 1947, Hospitalitermes ferrugineus (John, 1925), Hospitalitermes lividiceps , Hospitalitermes diurnus Kemner, 1934, and Hospitalitermes seikii Syaukani, 2010 by comparing the head capsule; in dorsal view the posterior margin and the median portion of head capsule of Hospitalitermes nigriantennalis are elongated. In other species the head capsule is less elongated, rounded.

Likewise, in lateral view, the dorsal outline (including nasus) in profile weakly separate this new species from congeners (e.g., Hospitalitermes umbrinus , Hospitalitermes birmanicus (Snyder, 1934), Hospitalitermes bicolor (Haviland, 1898), Hospitalitermes monoceros (Koenig, 1779), Hospitalitermes papuanus Ahmad, 1947, Hospitalitermes jepsoni (Snyder, 1934) and Hospitalitermes krishnai Syaukani, 2011 by its elongate form.

Material examined.

Holotype: soldier collected from a mass processional column on the forest floor (leaving nest to feeding sites) in an undisturbed lowland rain forest (250 m in altitude), Pararawen Nature Reserve (0°38 ’13” S; 114°41 ’10” E), North Barito, Central Kalimantan, Borneo. The nest was located in soil at the base of a dead standing tree ( Shorea sp.), 6 m in height. Syaukani leg. 22.vi.2014. Colony code: SY-2014-Pararawen-0036. Other material from the same locality: SY-2014-Pararawen-C0045, C0051, C0052, C0059 (collected from nests at the base of standing tree), SY-2014-Pararawen-C0019, C0037, C0043 (collected from a processional column en masse). The holotype is deposited at Museum Zoologicum Bogoriense (MZB), Cibinong, Indonesia. Paratypes: soldiers and workers from C0019, C0036, C0037, C0043, C0045, C0051, C0052; will be depository at MZB, the Natural History Museum, London (UK), Natural History Museum Vienna (Austria), Syiah Kuala University, Darussalam, Banda Aceh (Indonesia), the Kitakyushu Museum of Natural History and Human History (Japan), and the American Museum of Natural History, New York (USA).

Etymology.

This species is named after the blackish antennae in the soldier caste.

Biological observation.

With the discovery of this new species, the total number of Hospitalitermes species increased to eight for the island of Borneo. This species foraged above the ground and seemed to prefer leaf litter, which may afford some protection from predators. However, when huge logs or fallen trees disrupt this cover, the soldiers can be seen running in a zigzag pattern along the column edges. This observation of soldier behavior is consistent with observations by Hoare and Jones (1998) who reported this response in Longipeditermes longipes as a response to disturbance. The strong dimorphism in coloration between the soldier and worker castes is peculiar among the members of this genus, and distinguishes this species. Finally, Hospitalitermes nigriantennalis has a dimorphic worker caste.