Proboscitermes mcgrewi Scheffrahn

Scheffrahn, Rudolf H. & O’Malley, Robert C., 2010, A new termite (Isoptera: Termitidae: Termitinae: Proboscitermes) from Tanzania, Zootaxa 2670, pp. 52-58 : 54-57

Proboscitermes mcgrewi Scheffrahn sp. nov.

( Figs. 2 –6)

Description. Imago ( Fig. 2 AB). Winged imago unknown. Head and dorsum of physogastric queen brown; measurements (mm): entire body length 22.7, max dorsal body width 4.3, fourth anterior tergite 1.36 wide by 0.40 long, maximum head width 1.56, eye maximum diameter 0.23, pronotum 0.94 wide by 0.54 long.

Soldier ( Figs. 3 A–E, 4). Monomorphic. Body whitish; digestive tube whitish and highly reduced; tube devoid of granualar contents. Body dimensions proportionally small in comparison to head; body smaller than that of worker. Head capsule light orange grading to ferruginous orange toward frontal lobe. Body coloration hyaline except for yellowish pronotum. Surface of head capsule and mandibles with fine shagreened texture. Head capsule pentagonal in dorsal and ventral views; quadrate frontal lobe in lateral view suggestive of a sperm whale head. Large fontanelle directed anteroventrally to saturate surrounding dense tuft of setae with clear defensive secretion; 6 long setae on anterodorsal hump of frontal lobe; a few more long setae near occiput. Labrum quadrate with triangular points at anterolateral corners; eclipsed from dorsal view by frontal lobe. Pronotum with about 10 long setae near posterior margin; 8–10 long setae scattered along each tergite and sternite; especially prominent a lateral margins. Mandibles taper evenly to tips, surface shagreened, tips incurved; very small triangular tooth at base of each mandible. Mandibles extend three-quarters their length beyond frontal lobe. Distinct ridge on gena behind antennal sockets; antennae with 14 articles, 2=3>4<5 or 2>3=4<5. In lateral view, postmentum with blunt peak near its posterior fourth. Measurements (n = 12; 2, 4, 1, and 5 from each paratype colony; mean±SD (range) in mm: max head length without mandibles 1.43±0.055 (1.33–1.51); maximum head width 1.07±0.017 (0.89–1.09); head height without postmentum 0.93±0.026 (0.86–0.96); mandible articulation to distal margin of frontal lobe 0.37±0.024 (0.32–0.42); left mandible length 1.39±0.032 (1.36–1.46); maximum pronotum height 0.28±0.032 (0.25–0.35); maximum pronotum width 0.58±0.021 (0.54–0.62); hind tibia length 0.88±0.032 (0.84–0.91).

Worker ( Figs. 2 C, 4, 5). Monomorphic, worker body larger than that of soldier, postclypeus moderately inflated but external morphology otherwise unremarkable. Head capsule hyaline, abdominal cuticle moderately transparent. Darker elongate patches consisting of spiny cushions of the enteric valves visible from P1 to P2 transition zone to P2 constriction at insertion of P3. Antennae with 14 articles. Enteric valve armature triradial with 6 primary and 6 smaller subsidiary cushions; three larger primary cushions consisting of about 6 rows of medium erect spines in the proximal 4/5ths; distal 1/5th with spine more robust becoming shorter, thinner, and more curved at terminus. Three smaller primary cushions with about 6 rows of medium erect spines at anterior becoming longer, more curved, and reduced to 2–3 rows at terminus. Primary cushions separated by 6 subsidiary cushions consisting of about 10 anterior small erect spines with posterior of cushion consisting of 4–6 rows of very small erect spines. Apical teeth of both mandibles prominent, much larger than marginal teeth, dentition as in Fig. 2 C. Worker maximum head width (n = 12, 3 each from 3 paratype colonies; mean±SD (range): 0.82mm ±0.028 (0.79–0.86).

Diagnosis. The frontal lobe of Proboscitermes mcgrewi is distinct from other soldiers in the Cubitermes group by its large anterior volume and broad sloping profile ( Fig. 3 A–E). P. tubuliferous ( Fig. 3 F) and U. gaerdesi are closest to P. m c g re w i but the former have much narrower and more conical nasus, especially in lateral view. The soldier labrum of U. gaerdesi is incised, forming a pair of isosceles triangles (Fig. 11E in Coaton 1971) and lacks triangular points at the anterolateral corners ( Fig. 3 D) seen in both Proboscitermes spp. Sands (1998) generic description of Proboscitermes workers includes P. tubuliferous and a new species from Cameroon. Based on Sands 1998 photographs of worker enteric valves, both of these Proboscitermes species differ from P. m c g re w i ( Fig. 5 ) in that P. tubuliferous has more stout curved spines in the posterior ends of the primary cushions and P. sp. nov. has shorter, more ovoid primary cushions. The enteric valve armature of U. gaerdesi has wider secondary cushions with stouter spines (Fig. 6 on Plate 13 in Sands 1998).

Material examined. Holotype soldier: Lat./Long. -4.66445/29.62586, 18JAN2010, elev. 827 m, in mound in forest with four other soldiers, many workers and physogastric queen, (UF code AFR1142). Three other paratype colonies: -4.67843/29.63102, 19DEC2009, 1079 m (AFR554), 2 soldiers with workers; - 4.65284/29.63469, 28DEC 2009, 907 m (AFR667) four soldiers with workers; and -4.66463/29.62618, 30DEC 2009, 808 m (AFR766) one soldier with workers. All samples collected by RCO. The type and paratypes are deposited in the University of Florida Termite Collection (Ft. Lauderdale Research and Education Center, Davie, Florida). Additional paratypes will be deposited in the Florida Collection of Arthropods (Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville, Florida)

Etymology. This species is in honor of William C. McGrew, a primatologist at the University of Cambridge, UK, who has studied chimpanzees (including those of Gombe Stream National Park) in the wild and in captivity for over thirty years. Dr. McGrew has published numerous books and papers highlighting the ecological importance of insect consumption by nonhuman primates, particularly chimpanzees, and the relevance of insectivory for understanding human evolution (e.g., McGrew 1992, McGrew 2001).

Habitat and biology. Gombe Stream National Park is a mosaic habitat of evergreen forest (mostly concentrated in riverine valleys), woodland thicket, dense vine tangle, and open woodland (grading into grassland) ( Collins and McGrew 1988). Four P. mcgrewi samples were collected from epigeal soil mounds and a dead tree across three habitat classes (woodland thicket (twice), evergreen forest, and vine tangle) between 827–1079 m elevation and within 1.1 km of the eastern shore of Lake Tanganyika. Two soil mounds were relatively small and round (AFR1142 was 40cm diameter, while AFR554 was 20cm in diameter) and required a geological hammer to break open. One sample (AFR766) was an inquiline in a large (4.2m wide, 4mh) otherwise moribund Macrotermes mound. Sample AFR667 was collected from a dead tree, together with an unknown ant species. Sjöstedt (1925) reports that Silvestri collected P. tubuliferous from earthen foraging tubes under a tree stump. The lack of solid organic contents in the soldier digestive tube suggests that nutrition is derived from worker exocrine gland secretions.

Figures

FIGURE 2. Proboscitermes mcgrewi physogastric queen. A) Dorsal habitus (bar = 10 mm), B) dorsal view of head and thorax (bar = 1 mm). Worker mandibles C) dorsal view (bar = 0.2 mm).

FIGURE 3. Proboscitermes mcgrewi soldier. A) lateral, B) ventral, and C) dorsal views of head and thorax (bar = 1 mm). D) Oblique anterior view showing labrum and fontanelle, and E) lateral view showing pilosity around fontanelle (bar = 1 mm). F) Lateral view of P. tubuliferous soldier head redrawn without setae from Sjöstedt 1925.

FIGURE 5. Enteric valve armature of P. m c g re w i worker. Left: entirety of two of three larger primary cushions, two of three smaller primary cushions, and three of six subsidiary cushions (bar = 0.2 mm). Right: posterior portions of two larger primary cushions, one smaller primary cushion, and subsidiary cushions interspersed (bar = 0.1 mm).