Temnothorax peninsularis

Known from two females.

Identification
Mackay (2000) - A member of the Temnothorax hispidus species complex. This species is known only from the female, which is a small, light brown ant. The head is entirely sculptured with coarse rugae, and is punctate between the rugae. The antennae have 12 segments and the scapes extend slightly past the occipital comers. The sculpture of the mesosoma is very similar to that of the head, the propodeal spines are large, well developed with thick bases. The petiole has a long peduncle with a square node. The postpetiole and gaster are missing, but Wheeler (1914) states that the gaster is smooth and shining. The rough sculpture and the shape of the petiole (long peduncle, quadrate node) would probably separate this species from all others in the New World. It would also be easily to recognize as it is presently one of the only 2 species known from the Baja peninsula (The other is Temnothorax andrei, undoubtedly others occur there).

This species is difficult to place in any subgenus as it is somewhat intermediate between the subgenus Myrafant and what was previously considered the subgenus Macromischa (synonymized by Snelling, 1986). It is not closely related to Nesomyrmex (=Goniothorax) as Wheeler (1934) speculated, as there are no spines on the petiole. Characters in common with Macromischa would include the structure of the clypeus, which is somewhat bulging dorso ventrally and is covered with striae and the petiole has a long peduncle. On the other hand, the peduncle is not as elongate as in most Macromisha and is not that different from some of the Myrafant, such as Temnothorax silvestrii and Temnothorax punctaticeps, in which the clypei are similar. It is also possible that it is a member of the subgenus Dichothorax. It can be easily separated from Temnothorax pergandei as it is much more roughly sculptured. The entire head is rugose with punctures between the rugae. The head of the female of Temnothorax pergandei is predominantly smooth and glossy. The sculpture of the mesosoma of Temnothorax peninsularis is rugose, similar to the head. Nearly the entire mesosoma of the female of Temnothorax pergandei is smooth and glossy. This species could also be I confused with Temnothorax rugithorax, but can separated by the pedunculate petiole and the well-developed propodeal spines. We will be able to further clarify the proper placement of this species once the workers are known, but in the meantime I propose that we consider this species a member of Myrafant and of the hispidus species complex.

Distribution
Mexico: Magdalena Bay, Baja California Sur.

Distribution based on Regional Taxon Lists
Neotropical Region: Mexico.

Abundance
Only known from types.

Nomenclature

 *  peninsularis. Leptothorax (Goniothorax) peninsularis Wheeler, W.M. 1934f: 134 (q.) MEXICO. Combination in Temnothorax: Bolton, 2003: 272. See also: Mackay, 2000: 386.

Queen
Length about 5 mm.

Head subrectangular, slightly longer than broad, nearly as wide anteriorly as posteriorly, with rounded posterior corners and straight posterior border. Eyes convex, at the middle of the sides. Mandibles small, with straight external borders and about six small teeth. Clypeus convex, its anterior border straight and transverse in the middle, sinuate on each side. Antennae 12-jointed; scapes reaching somewhat beyond the posterior corners of the head; funiculi with joints 2 to 6 as long as broad, remaining joints longer than broad, the last three forming a distinct club, with the basal two joints subequal and together as long as the terminal joint. Thorax large and robust, broader than the head; pronotum with prominent, rectangular but not acute humeri; mesonotum and scutellum flattened above, the former subhexagonal, very nearly as broad as long; epinotum with somewhat convex base, shorter than the perpendicular declivity; spines large and stout, acute, longer than their basal diameter, but shorter than their distance apart. Petiole with well-developed peduncle and stout anteroventral tooth; node sub cuboidal, slightly broader than long, its latero-superior border distinctly denticulate anteriorly; postpetiole much broader than the petiolar node, from above transversely rectangular, nearly twice as broad as long, its posterior border emarginate in the middle. Gaster large, elliptical, with straight anterior border. Wings with large pterostigma, small discoidal cell and very short, closed marginal cell.

Subopaque; venter smooth and shining; mandibles very finely striate; clypeus and head longitudinally and rather finely rugulose, the rugules becoming more reticulate laterally and posteriorly. Pronotum, mesonotum and scutellum evenly rugulose and glossy, the rugules on the pronotum transverse anteriorly, longitudinal on the sides and on the mesonotum and scutellum; remainder of thorax finely punctate-rugulose; the epinotal declivity anteriorly and posteriorly very finely and transversely rugulose. Gaster above and appendages very finely and densely punctulate; bases of the second and following gastric segments smooth and shining.

Hairs pale yellowish; numerous, obtuse and very short on the head and thoracic dorsum, somewhat longer on the gaster. Scapes and legs with very fine, short, appressed pubescence.

Ferruginous; mandibles, clypeus, cheeks, sutures of thorax and legs brownish yellow; ocellar area fuscous; wings faintly tinged with yellow; veins brown; pterostigma darker brown, especially along its posterior border.

Type Material
Mexico. Baja California Sur. Magdalena Bay.

References based on Global Ant Biodiversity Informatics

 * Fernandes, P.R. XXXX. Los hormigas del suelo en Mexico: Diversidad, distribucion e importancia (Hymenoptera: Formicidae).
 * Johnson, R.A. and P.S. Ward. 2002. Biogeography and endemism of ants (Hymenoptera: Formicidae) in Baja California, Mexico: a first overview. Journal of Biogeography 29:10091026/
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Wheeler, William Morton. 1934. Ants From The Islands Off The West Coast Of Lower California and Mexico. The Pan-Pacific Entomologist. 10(3):131-144.