Lophomyrmex ambiguus

The holotype was collected from sifted leaf litter.

Identification
A member of the Lophomyrmex bedoti group.

Rigato (1994) - L. ambiguus may be confused with Lophomyrmex striatulus (see there) and Lophomyrmex bedoti, but it is more distinctly sculptured than the latter. Moreover L. bedoti has slightly smaller eyes, which are about 1.5 times their maximum length from the mandibular insertion in lateral view. The propodeal spines of L. ambiguus look shorter and thicker in profile. The petiolar node of L.ambiguus is not so clearly obliquely truncate as in L. bedoti. Also L. ambiguus is usually darker and with a deeper metanotal groove.

Distribution based on Regional Taxon Lists
Oriental Region: Bangladesh, India, Nepal.

Nomenclature

 *  ambiguus. Lophomyrmex ambiguus Rigato, 1994a: 52, figs. 14, 15 (w.) INDIA.

Worker
Holotype: TL 3.1, HL 0.80, HW 0.75, CI 94, SL 0.68, SI 91, PW 0.49, AL 0.95, SpL 0.23, HTL 0.69, TI 92.

In lateral view the distance between the mandibular insertion and the anterior point of the eye is about 1.3 times the maximum eye length. Mesonotum in profile with feeble prominence and posterior step: both, as usual, marked by a couple of erect hairs. Metanotal groove distinct in profile. Propodeal spines in profile straight, not very long and with a quite wide base from which they gradually taper toward the tips. Petiolar node in profile high and briefly subtruncate. Its anterior and superior faces meet at a rounded angle: posteriorly there is an evenly rounded, well-defined, step. Postpetiole not massive, clearly shorter than the petiole and about as high as that. In dorsal view the postpetiole is about 1.6 times wider than the petiole.

Clypeus finely reticulate, sublucid except for its posteriormost median portion which is smooth. Frontal triangle mostly shagreened, only partially shining. Cephalic dorsum finely reticulate throughout and quite dull, chiefly on the portions contained between the level of the inner margin of the eyes and the frontal lobes: frons sublucid in the middle. Genae and frontal lobes with tiny longitudinal rugulae: those on the frontal lobes look long and fragmented and reach the vertex (they are more visible in oblique view). Ventral head surface with some anteriorly convergent faint rugulae. Anterior slope of the pronotum reticulate and sublucid. Pronotal dorsum between the lateral margins quite shining and irregularly sculptured, feebly reticulate with few short faint rugulae anteriorly; a blunt poorly defined longitudinal median carina also occurs. Pronotal sides shining, with very superficial longitudinally oriented reticulation. Mesonotum reticulate, sublucid: mesopleuron more strongly reticulate, dull. Propodeum reticulate, subopaque, excluding the smooth space between the spines and the declivity. Petiole and postpetiole clearly reticulate on the sides; the nodes only faintly reticulate and moderately shining. Gaster shining, very superficially reticulate; the reticulation is not continuous on the whole surface.

Pilosity as usual in the genus. Pubescence very sparse, subdecumbent on the alitrunk, more abundant on the head.

Colour chiefly light brown throughout; appendages slightly lighter.

Additional workers: TL 2.8-3.4, HL 0.70-0.85, HW 0.64-0.81, CI 91-96, SL 0.59-0.71, SI 86-92, PW 0.44-0.54, AL 0.84-1.03, SpL 0.20-0.28, HTL 0.61-0.75, TI 89-96 (7 paratypes and 6 non-paratypes measured).

As the holotype but varying as follows:

Eye distance from the mandibular insertion often 1.4 times the maximum eye length. Propodeal spines may be slightly bent downward in profile. Sometimes the sculpture is less developed, chiefly in smallest specimens; the head is a little more superficially reticulate and its ventral surface may be shining and without any recognizable faint rugulae. The pronotum may be devoid of short rugulae.

Colour often lighter on the sides of head and alitrunk.

Type Material
Holotype worker, India: Uttar Pradesh, Kuamun District, Kathgodam, 6OOm, 6.x.I979, sifted leaf litter (I. Lobl). Paratype workers, 2 specimens with the same data as the holotype (ANIC); 2 specimens, India: Uttar Pradesh, Dehra Dun, 30. viii. 1978 (H. [mail ('Indian ants cytology', voucher specimens n°.78-6O) (ANIC) [misidentified as L.bedoti]; 3 specimens, India: NE India, without locality and date (Kurl) (BMNH; ).



References based on Global Ant Biodiversity Informatics

 * Bharti H., Y. P. Sharma, M. Bharti, and M. Pfeiffer. 2013. Ant species richness, endemicity and functional groups, along an elevational gradient in the Himalayas. Asian Myrmecology 5: 79-101.
 * Bharti H., and R. Kumar. 2012. Lophomyrmex terraceensis, a new ant species (Hymenoptera: Formicidae) in the bedoti group with a revised key. Journal of Asia-Pacific Entomology 15: 265-267.
 * CSIRO Collection
 * Hannan M.A. 2008. New ant records fro Bangladesh. Asian Myrmecology 2: 95-98.
 * Rigato F. 1994. Revision of the myrmicine ant genus Lophomyrmex, with a review of its taxonomic position (Hymenoptera: Formicidae). Systematic Entomology 19: 47-60.
 * Sheela S., and S. N. Ghosh. 2009. A new species of Lophomyrmex Emery (Hymenoptera: Formicidae) from India with a key to Indian species. Biosystematica 2(2): 17-20.