Tetramorium muralti

Tetramorium muralti is a very common and abundant species regularly found in the rain forest leaf litter in West Africa and the Congo Basin.

Identification
The following character combination clearly distinguishes T. muralti  from all other species of the complex: anterior clypeal margin entire; postpetiole moderately cuneiform without sharp dorsal margin, always distinctly less than twice as wide as long (DPpI 173 - 192); cephalic dorsum with 3 longitudinal rugae between frontal carinae; dorsum of mesosoma generally unsculptured, except for short rugulae anteriorly and at bases of propodeal spines.

A member of the Afrotropical muralti species complex, which is part of the weitzeckeri species group.

Key to weitzeckeri-group species.

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Central African Republic, Democratic Republic of Congo, Gabon, Ghana, Ivory Coast, Uganda.

Nomenclature

 *  muralti. Tetramorium (Xiphomyrmex) muralti Forel, 1910e: 429 (w.) CAMEROUN. Santschi, 1914d: 368 (q.). Combination in Xiphomyrmex: Santschi, 1919h: 88; in Tetramorium: Bolton, 1980: 229. Senior synonym of trilineata: Bolton, 1980: 229. See also: Hita Garcia, Fischer & Peters, 2010b: 53.
 * trilineata. Xiphomyrmex muralti var. trilineata Santschi, 1919h: 88 (w.q.) GHANA. Junior synonym of muralti: Bolton, 1980: 229.

Hita Garcia et al. (2010) - This species is the core species of the "muralti complex and can be well distinguished from the rest of the complex. It can be simply separated from Tetramorium susannae since the latter possesses only 1 median longitudinal ruga between the frontal carinae whereas there are always 3 rugae in Tetramorium muralti , often interrupted but always 3. In addition, the postpetiole is sharply cuneiform and transverse in T. susannae (DPpI 216 - 264) while it is rounded cuneiform without sharp dorsal margin and less transverse in T. muralti  (DPpI 173 - 192). Additionally, the entire and convex anterior clypeal margin in T. muralti  divides it from Tetramorium akengense, Tetramorium kakamega, and Tetramorium occidentale. Furthermore, the species with conspicuously rugose or rugulose mesosomal dorsum, Tetramorium flavithorax, Tetramorium intermedium, and Tetramorium trirugosum, cannot be confused with T. muralti '' since the mesosoma of the latter is mostly unsculptured with weak rugulation only.

Worker
Hita Garcia et al. (2010) - HL 0.494 - 0.556 (0.529); HW 0.467 - 0.522 (0.500); SL 0.322 - 0.372 (0.349); EL 0.117 - 0.144 (0.127); PW 0.356 - 0.411 (0.385); WL 0.556 - 0.644 (0.609); PSL 0.139 - 0.167 (0.157); PTL 0.072 - 0.094 (0.082); PTH 0.217 - 0.250 (0.233); PTW 0.178 - 0.217 (0.198); PPL 0.122 - 0.150 (0.137); PPH 0.183 - 0.228 (0.208); PPW 0.222 - 0.278 (0.255); CI 92 - 98 (95); SI 67 - 73 (70); OI 24 - 29 (25); PSLI 28 - 31 (30); PeNI 47 - 56 (51); LPeI 32 - 40 (35); DPeI 224 - 257 (241); PpNI 61 - 71 (66); LPpI 59 - 74 (66); DPpI 173 - 192 (186); PPI 119 - 138 (128) (51 measured).

Head longer than wide (CI 92 - 98). Anterior clypeal margin entire and generally convex. Frontal carinae strongly developed and sinuate, curving down ventrally shortly before posterior margin of head and forming the posterior and ventral margin of antennal scrobe. Scrobe well-developed, broad and relatively deep, with distinct sharp margin all around. Antennal scape short (SI 67 - 73). Eyes moderate to large (OI 24 - 29), with 7 to 9 ommatidia in longest row. Metanotal groove in profile never impressed. Propodeal spines long and spinose (PSLI 28 - 31). Propodeal lobes small and triangular with an acute apex. Petiolar node squamiform, in dorsal view usually between 2 to 2.5 times wider than long (DPeI 224 - 257) and between 2.6 to 3.2 times higher than long (LPeI 32 - 40). Postpetiole cuneiform, narrowly rounded dorsally without sharp margin, in dorsal view distinctly less than twice as wide as long (DPpI 173 - 192); in profile moderately antero-posteriorly compressed generally between 1.3 to 1.7 times higher than long (LPpI 59 - 74). Mandibles unsculptured, smooth and shiny. Clypeus with 3 longitudinal rugae, median ruga always strongly developed, lateral rugae variable; sometimes weak to moderate transverse median rugae present. Head mostly unsculptured, 3 longitudinal rugae present between frontal carinae, median ruga always well-developed, lateral rugae between median ruga and frontal carinae always present, usually unbroken and distinct, sometimes weakly developed, often interrupted, antennal scrobe with median longitudinal ruga anteriorly reaching eye level. No cephalic ground sculpturation visible. Dorsum of mesosoma generally unsculptured, often weak short longitudinal rugulae present on pronotal dorsum and at bases of propodeal spines. Petiole, postpetiole, and gaster completely unsculptured, smooth and shiny. All dorsal surfaces with simple, fine, standing hairs. Fine pubescence on tibiae and antennal scapes appressed to subdecumbent. Colour uniformly brown to very dark brown, nearly black, appendages lighter but of variable coloration, in specimens from Ghana, Gabon, and D.R. Congo all appendages uniformly yellow, in material from Cameroon, Central African Republic, and Ivory Coast appendages brown except for whitish tibiae.

Type Material
Hita Garcia et al. (2010) - Holotype worker, CAMEROON, no location, leg. L. von Muralt [examined].

Xiphomyrmex muralti var. trilineata. Syntype worker, female, GHANA, Aburi, 1913, leg. F. Silvestri [examined].

Additional References

 * Hita Garcia, F.; Fischer, G.; Peters, M. K. 2010. Taxonomy of the Tetramorium weitzeckeri species group (Hymenoptera: Formicidae) in the Afrotropical zoogeographical region. Zootaxa 2704:1-90.