Myrmica afghanica, Radchenko, A. G. & Elmes, G. W., 2003

Radchenko, A. G. & Elmes, G. W., 2003, Myrmica afghanica (Hymenoptera: Formicidae), a new ant species from Afghanistan., Zootaxa 375, pp. 1-8 : 3-7

Myrmica afghanica , sp. nov.

= M. tibetana : Collingwood 1961: 36, 6w, 1q, Afghanistan, Pashki Nuristan, 6.iv. (sic!), [19]48, leg. K. Paludan, misidentification, not Mayr, 1889: 279 et al.

Material examined. Holotype worker, " Afghanistan, Pashki Nuristan, 6.vi. (sic!) 48, leg. K. Paludan ";

paratypes: 2 workers and 1 queen (dealate, specimen without postpetiole and gaster), same labels as holotype (University Museum Copenhagen).

Description

Workers (Figs 1-6): Head long, with parallel sides, straight or very feebly concave occipital margin, and narrowly rounded occipital corners. Anterior clypeal margin prominent and pointed medially. Frontal carinae short, almost straight, not curving outwards to merge with the rugae, which surround antennal sockets. Frons wide, frontal lobes relatively narrow (see indices below). Antennal scape long and slender, very feebly curved at the base, without trace of angle or carina. Alitrunk dorsum feebly convex, metanotal groove very shallow. Propodeal spines short but sharp, projected backwards and upwards (at an angle about 45°). Petiole with long anterior peduncle, in profile petiolar node dorsum broadly rounded and postpetiole sub-globular.

Head dorsum having mostly a relatively coarse, longitudinal rugulosity, only the lateral parts and occiput having reticulation. Frons between frontal carinae level with the eyes with less than 13 rugae. Surfaces between rugae appearing shiny, being at most very finely, superficially sculptured. Promesonotal dorsum mostly longitudinally rugose, only anterior half of pronotum with coarse reticulation; sculpture on propodeal dorsum partly reduced; sides of alitrunk with longitudinal, slightly sinuous rugae. Petiolar and postpetiolar nodes with longitudinally-concentric rugae. Tibiae of hind and middle legs with well developed, pectinate spur. Quite hairy species. Antennal scape and legs with very abundant and long hairs that are almost erect on scape and sub-erect on legs; the longest hairs on antennal scape distinctly longer than maximal diameter of the scape. Body colour light brown to black, appendages yellowish brown.

Measurements (mm) and indices (data for holotype in parenthesis): HL 1.02-1.12 (1.06), HW 0.82-0.88 (0.84), FW 0.35-0.39 (0.36), FLW 0.37-0.40 (0.39), SL 0.82 - 0.86 (0.86), AL 1.42-1.52 (1.50), HTL 0.74-0.82 (0.76), PNW 0.60-0.63 (0.60), PL 0.40-0.41 (0.40), PW 0.23-0.24 (0.24), PH 0.30-0.33 (0.31), PPL 0.32-0.33 (0.33), PPW 0.36 (0.36), PPH 0.36-0.39 (0.36), ESL 0.19-0.23 (0.19), ESD 0.34 (0.34); CI 1.24-1.27 (1.26), FI 0.43-0.44 (0.43), FLI 1.03-1.06 (1.06), SI1 0.75-0.81 (0.81), SI2 0.95-1.02 (1.02), PI1 1.24-1.33 (1.32), PI2 0.47-0.49 (0.49), PPI1 0.85-0.92 (0.92), PPI2 1.00-1.08 (1.00), PPI3 1.50-1.56 (1.50), PPI4 0.41-0.44 (0.43), ESLI 0.23 -0.26 (0.23), ESDI 1.48-1.79 (1.79), HTI 0.45-0.47 (0.45).

Queen (specimen without postpetiole and gaster) (Figs 7-12): Relatively small compared to queens of many Myrmica species but proportionately larger than the workers (about 25% larger on both HW and AL). Otherwise the general features of shape, sculpture and pilosity are very similar to the workers. It differs from the workers by the slightly convex lateral margins of the head, and the following details of the body sculpture: just longitudinal rugae present on the head dorsum and alitrunk with no reticulation; only the petiolar node dorsum has any reticulation. Postpetiole and gaster most probably also very similar to those of workers.

Measurements (mm) and indices: HL 1. 26, HW 1.06, FW 0.45, FLW 0.47, SL 1.00, AL 1.88, HTL 1.00, PL 0.51, PW 0.33, PH 0.43, ESL 0.19, ESD 0.42; CI 1.19, FI 0.42, FLI 1.04, SI1 0.75, SI2 0.94, PI1 1.55, PI2 0.48, ESLI, 0.18, ESDI 2.21, HTI 0.47, AI 1.59, SCI 1.62.

Etymology. This species is named after Afghanistan where it is probably endemic.

Distribution and ecology. We cannot find Pashki Nuristan, but the most probable locality is Nurestan (34°56' N, 70°22' E) located in a river valley of the Hindu Kush, about 60 km north of Jaelaelaebad and 120 km northeast of Kabul. If we are correct and M afghanica is a member of the rubra species-group (see below), then it might be distributed more widely in the Hindu Kush mountains of Afghanistan, northwards into the adjacent territories of Tadzhikistan and the western slopes of the Pamirs. On the other hand, it could be a true Himalayan endemic belonging to the smythiesii-group (see below) either with a restricted local distribution or perhaps also living on the lower slopes of the Karakorum in Pakistan and northwest India. Nothing is known about its ecology but if we have truly identified the type locality, then it probably lives at lower altitudes (1000-2000m) where it is should be associated with river valleys.

Taxonomic position and discussion. Until the features of the males of M. afghanica are described it is impossible to place it, with any certainty, in known Myrmica speciesgroups(see Radchenko and Elmes 2001). Based on the female castes M. afghanica could belong to either the rubra-group or the smythiesii-group . It is most similar to the species of the dshungarica-complex of the rubra species-group, which are distributed in Central Asia, and therefore, like M. tenuispina , it might have invaded Afghanistan from the north. On the other hand if it belongs to the smythiesii-group it is probably a true endemic of the region.

Workers and queens of the species in the rubra- and smythiesii-groups are characterized by a long and slender antennal scape, which is gently curved at the base without any angle or carina, by their short, almost straight frontal carinae and wide frons (FI> 0.40) and quite narrow frontal lobes (FLI <1.15). Males from these groups are characterized by a quite long antennal scape, but the scape of rubra-group males is even longer than that of the smythiesii-group (Radchenko and Elmes 2001). Workers and queens are relatively small, like many other species in the rubra-group .

With the current knowledge M. afghanica can no longer be confused with M. tibetana despite M. tibetana being placed in the rubra-group by Radchenko (1994a). We considered this earlier opinion wrong and proposed that M. tibetana characterizes its own species-group(Radchenko and Elmes 2001) because it appears to have more in common with species from the scabrinodis-group rather than species from either the rubra- or smythiesii-groups . For example, workers of the species belonging to the tibetana-group are characterized by frontal carinae curved at their anterior third and frontal lobes that are relatively wide and sub-square (FLI> 1.30 versus <1.15), features typically seen in scabrinodis-group species. Also the males of tibetana-group species have a short antennal scape like those of the scabrinodis-group . However, the scabrinodis-group clearly differs from the tibetana-group by its S-shaped frontal carinae that are curved from their midlength.

If M. afghanica is a member of the dshungarica-complex (i.e. M. dshungarica , M. juglandeti , M. ferganensis and M. kryzhanovskii which mainly live in the Tien-Shan and Pamir Mountains - see Radchenko 1994a) then it most resembles M. kryzhanovskii . Both have long and abundant standing hairs on the legs and antennal scape but M. afghanica differs from M. kryzhanovskii by its prominent and medially-pointed anterior clypeal margin, by much shorter propodeal spines (ESLI 0.23-0.26 versus> 0.30) and by a relatively coarser longitudinal rugosity on the head dorsum (frons between frontal carinae level with the eyes with less than 13 rugae versus more than 15 in M. kryzhanovskii ).

The other three species have much less abundant and shorter hairs on their legs and antennal scapes. M. afghanica also differs from M. dshungarica by the parallel sides of its head, as opposed to convex sides, by a much longer petiolar peduncle and by the distinctly concave anterior surface and rounded dorsum of the petiolar node, versus the steep anterior surface and distinctly flattened dorsum of the petiolar node seen in M. dshungarica . M. afghanica's prominent and pointed anteromedian clypeal margin well separates it from both M. juglandeti and M. ferganensis , which have less prominent and broadly-rounded anteromedian clypeal margins (see also Arnoldi 1976; Tarbinsky 1976; Radchenko 1994b).