Tetramorium transformans

In Yemen this species was collected from dry leaf litter under a tree of Ficus cordata Thunb (Moraceae) (Sharaf et al., 2017). Several workers were foraging in dry soil under a date palm tree. A nest was found in moist leaf litter rich in decaying organic materials of animal faeces and next to a stream near date palm trees. A nest was found in galleries of a termite nest under a rock and coexisting with a nest of Monomorium exiguum.

Identification
Worker. Eyes of eight ommatidia in longest row; frontal carinae running back beyond posterior level of eyes; head and gaster yellowish, first gastral tergite darker than gaster, mesosoma, petiole and postpetiole reddish distinctly contrasting rest of body. (Sharaf et al., 2017)

Distribution
This species was originally described from Kenya (Santschi 1914) and since been found in the Socotra Archipelago, Yemen (Sharaf et al., 2017).

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Socotra Archipelago, Yemen.

Nomenclature

 *  transformans. Tetramorium pauper st. transformans Santschi, 1914b: 104 (w.) KENYA.
 * Junior synonym of caldarium: Bolton, 1980: 310.
 * Status as species: Sharaf et al., 2017: 361.

Taxonomic Notes
Sharaf et al. (2017) - Bolton (1980) synonymized Tetramorium transformans under Tetramorium caldarium. However, Tetramorium transformans can be readily separated from Tetramorium caldarium by the following characters: cephalic dorsum with scattered longitudinal feeble rugulae, with ground-sculpture shining and weakly imbricate. Frontal carinae less-developed, ending back at the posterior levels of eyes. Whereas Tetramorium caldarium has the cephalic dorsum feebly densely finely longitudinally rugulose, with ground-sculpture dull, finely, conspicuously punctulate or granulate. Frontal carinae well-developed running back beyond the posterior levels of eyes, feebly defined, and interrupted before reaching posterior margin of head.

Tetramorium transformans was originally described as a strain under Tetramorium pauper Forel, 1907. Comparing Tetramorium transformans with Tetramorium pauper, both are similar in body size, sculpture and pilosity, but Tetramorium transformans is easily diagnosed by the larger eyes, with seven ommatidia in the longest row (EI 26), whereas eyes of Tetramorium pauper are consistently smaller, with four ommatidia in the longest row (EI 15). In addition, the frontal carinae in Tetramorium pauper are shorter and just reach back to midline of eyes, whereas Tetramorium transformans has a longer and stronger frontal carinae running back to the posterior level of eyes. The eyes structure and size are important diagnostic characters in the genus Tetramorium (Francisco Hita Garcia & Barry Bolton, personal communication 2016), Therefore, Tetramorium transformans is removed from synonymy with Tetramorium caldarium and recognized as a valid species.