A new species of open-air processional column termite, Hospitalitermes nigriantennalis sp. n. (Termitidae), from Borneo

Abstract A new species of open-air processional column termite is here described based on the soldier and worker castes from eight colonies in north Barito, central Kalimantan. Hospitalitermes nigriantennalis sp. n. is readily distinguished in the field from related Hospitalitermes spp. by the light brown to orangish coloration of the soldier head capsule that, further, is with vertex yellowish and nasus brownish. The soldier antenna and the maxillary and labial palps are blackish. By contrast, soldiers from other species of Hospitalitermes from this region have a uniformly black head capsule and antennae. Finally, Hospitalitermes nigriantennalis sp. n. has a minute indentation in the middle of the posterior part of head capsule, which further helps to differentiate this new species from other Hospitalitermes from the Indo-Malayan and Austro-Malayan regions.


Material and methods
Specimens of Hospitalitermes nigriantennalis sp. n. were collected from a processional column on the primary forest floor in Pararawen Nature Reserve, Muara Teweh, North Barito, Central Kalimantan (Borneo), Indonesia. The head, body (in profile), pronotum and antenna of the soldier caste (preserved in 70% ethanol) were photographed using a digital microscope (Olympus SZX12 and Nikon DS-Fi2, Japan). From these images, multi-focused montages were constructed using Helicon Focus 6.2.2 software (Helicon Soft Ltd. Kharkov Ukraine). General morphological terminology used for describing soldiers and workers follow Roonwal and Chhotani (1989), Sands (1998), Tho (1992) and Syaukani et al. (2011).
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 -14 th 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 -15 th gradually increasing in length. Left mandible: apical tooth clearly shorter than first marginal tooth;  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, H. 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 H. nigriantennalis can be distinguished from other regional congeners H. rufus, H. hospitalis, H. medioflavus, H. moluccanus Ahmad, 1947, H. ferrugineus (John, 1925), H. lividiceps, H. diurnus Kemner, 1934, and H. seikii Syaukani, 2010 by comparing the head capsule; in dorsal view the posterior margin and the median portion of head capsule of H. 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., H. umbrinus, H. birmanicus (Snyder, 1934), H. bicolor (Haviland, 1898), H. monoceros (Koenig, 1779), H. papuanus Ahmad, 1947, H. jepsoni (Snyder, 1934 and H. 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 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.