Taxonomy and distribution of the ant Cataglyphis setipes (Hymenoptera: Formicidae)

Abstract Taxonomy and distribution of the ant species Cataglyphis setipes (Forel, 1894) is herewith detailed. C. setipes is redescribed, based on workers, queens, and males. Photomontage images of all castes are provided. Information on the distribution and ecology of this species is also given. A key to the Indian species of Cataglyphis is presented.


Introduction
The ant genus Cataglyphis Foerster, 1850 is one of the most dominant groups of ants in arid zones of the Old World (Radchenko and Paknia 2010). It is distributed mainly in the Palaearctic region, with several species known from the deserts and semi-deserts of the Afrotropical and Oriental regions (Agosti 1990, Radchenko 1997, Bolton et al. 2007, Radchenko and Paknia 2010. It contains 89 valid species and 20 subspecies in the world fauna (Bolton 2014). This genus is represented by three species in India (Bharti et al. 2014): C. cugiai Menozzi, 1939, C. indica Pisarski, 1962 and setipes (Forel, 1894). C. setipes is relatively abundant and well represented in collections, but the species has a history of taxonomic confusion. Originally described in 1894, it was then incorrectly treated as a senior synonym of C. longipedem (Eichwald, 1841) by Radchenko in 1997 without any argumentation, although latter has the priority (Bolton 2014). However, Radchenko (personal communication, 2015) recognized the error, considers name C. longipedem as incertae sedis and accordingly revives C. setipes from synonymy and treats it as a valid species (Radchenko and Tinaut, in preparation).
Cataglyphis male genitalia are highly diverse with many distinct characters helpful in the species delimitation and as a basis for phylogenetic relationships within the genus (Agosti 1990). In recent times, more emphasis has been put on the male caste for identification of species in ant taxonomy due to the discovery of useful characters (Yoshimura and Fisher 2012). Unfortunately it is difficult to collect males since they have restricted periods of emergence throughout the year (Radchenko and Elmes 2010). With the capture of males in more species of ants in the future, it should become easier to classify species based on the characters expressed by males, which in turn will help to decrease the taxonomic impediment that has gripped the Indian ants (Bharti and Wachkoo 2012a, Bharti and Wachkoo 2012b, Bharti and Wachkoo 2012c, Bharti et al. 2014. Here we are contributing to the study of male ants in this genus by redescribing the male caste of C. setipes.

Materials and methods
The specimens were obtained by visual searching and hand-collecting. The morphological study was conducted with a Nikon SMZ 1500 stereo zoom microscope. For digital images, an Evolution MP digital camera was used on the same microscope with Auto-Montage (Syncroscopy, a division of Synoptics Ltd.) software. The images were processed with Adobe Photoshop CS5. Specimens have been deposited in PUPAC, Punjabi University Patiala Ant Collection. Some worker specimens will be deposited in BMNH, Natural History Museum, London, U.K. and CASC, California Academy of Sciences, San Francisco, United States of America. Morphological terminology for genitalia follow (Boudinot 2013) and for measurements (given in millimeters) and indices found below follow , Bharti and Wachkoo 2014b, Wachkoo and Bharti 2014b.

Materials
Mesosoma typical for this genus; pronotum convex; propodeum low, gradually arched, its dorsal surface distinctly longer than posterior one; propodeal spiracles distinctly slitlike, and very long; petiole obviously nodiform, with rounded node dorsum; long legs.
Surface of whole body covered with dense microreticulation, appears dull, although not strongly matt; mandibles striate with few scattered punctures.
Body with sparse standing pilosity, denser on head and the underside of gaster; pubescence minute and fine, relatively denser on mesosoma with a silvery glint; antennal funiculus with fine, short appressed to decumbent pubescence, scapes with suberect hairs; legs covered with dense macrosetae.
Head, mesosoma and node of petiole dark red; gaster black; legs a shade darker than mesosoma, almost black.
Queen (Fig. 2). As in major worker, with modifications expected for caste and the following differences: head narrower and scapes shorter than in major worker, surpassing posterior margin by three-tenths their length; clypeus subcarinate; mesosoma enlarged, mesonotum not constricted; petiole compressed anterolaterally, narrower in profile but wider in dorsal view than in major worker; mesepimeron with a posterodorsal (epimeral) lobe that covers mesothoracic spiracle and forms a seemingly isolated plate.  Head subquadrate about as long as wide; eyes subglobulose, convex, large and bulging, breaking head outline in full-face view; 3prominent ocelli present; antennae 13segmented, filiform, scapes long, surpass posterior margin of head by more than half their length; clypeus subcarinate in some specimens with round anterolateral corners; mandibles slender, curved and strap-like, apical tooth simple, acute, remainder without any dentition in some specimens and with well differentiated apical and basal tooth in some specimens.
Notauli absent; parapsidal lines prominent, diverging anteriorly; mesepimeron with a posterodorsal (epimeral) lobe that covers mesothoracic spiracle and forms a seemingly isolated plate; jugal lobe of hind wing absent; dorsal margin of petiole, in anterior view, shallowly concave to broadly round; propodeal declivity broadly rounded; propodeal spiracle elongate, slit shaped. Cataglyphis setipes (Forel, 1894 Basimeres large, broad at the base and tapering to a blunt point; in dorsal view, telomeres elongate anteroposteriorly, oval and rounded apically in lateral view covered by scrobiculae; both the basimeres and telomeres are setose; basimedialtelomeral process with flat broad parallel base, apex roughly dumbbell shaped, about one third the length of the telomere; cuspides small, triangular,with peg-like teeth on medial face, bent toward digiti; digiti smooth, much longer than cuspides, about 2 times the length of cuspides and usually bent towards each other apically; in lateral view digiti falcate and gently downcurved; penisvalva projecting with apices of each penisvalva directed posterolaterally. Subgenital plate concave and bilobed posterolaterally, with short triangular process in the centre of posterior margin.
Body covered with relatively more dense erect hairs especially on underside of gaster and parameres than in other conspecific castes, in addition to normal pubescence.

Diagnosis
This species most resembles C. indica from which it separates by lighter body colour; dense setae on tibiae and rounded propodeum whilst latter is characterized by darker body colour, sparse setae on tibiae and much angular propodeum. However, the workers are rather variable in the characters used to differentiate C. setipes and C. indica and therefore, discovery of males of C. indica in future, may prove pivotal in taxonomic decision regarding its validity based on the characters expressed by males.

Distribution
This is one of the most conspicuous ant species found commonly in arid and semiarid zones of Central and South Asia.

Ecology
This species inhabits subtropical areas and is relatively easy to find because they preferentially occupy open habitats. These ants have been observed to form permanent nests in dry soil; nests can be easily located in bare ground and along roadside. Workers of this species usually forage individually and raise gaster in locomotion.

Acknowledgements
Financial assistance rendered by the Ministry of Environment and Forests (Grant No. 14/10/2007-ERS/RE), Govt. of India, New Delhi is gratefully acknowledged. We are also thankful to AntWeb team (www.antweb.org) for their huge work. Sincere thanks are due to James C. Trager (Shaw Nature Reserve, USA) for langauge check and other helpful comments and suggestions about the manuscript. We are grateful to Alex Radchenko for confirming the status of the species. Sincere thanks to Donat Agosti and an anonymous reviewer for their valuable input.

Author contributions
Equally contributed.