Cataglyphis tartessica, Fernando AMOR & Patrocinio ORTEGA, 2014

Fernando AMOR & Patrocinio ORTEGA, 2014, Cataglyphis tartessica sp. n., a new ant species (Hymenoptera: Formicidae) in southwestern Spain, Myrmecological News 19, pp. 125-132 : 126-130

Cataglyphis tartessica sp.n.

Type material examined: Holotype (worker): Spain, Huelva, Doñana Biological Reserve 36° 59' 38.44" N, 6° 26' 47.74" W, 2009-07-03; coll. Museo Nacional de Ciencias Naturales de Madrid ( MNCN - Ent75407 ) . Paratypes: 72 queens (25 brachypterous and 47 ergatoids; DBR), 30 males ( DBR and ALC), and 181 workers ( DBR, AZN, ALC, UTR, BRN) collected between 2008 and 2010 .

Description of holotype worker: HL: 1.17 mm, HW: 1.13 mm, SL: 1.42 mm, ML: 1.90 mm, FL: 1.85 mm, CI: 96.58, SI: 125.66. Bicoloured: shiny black gaster, black eyes and ocelli, rest of body amber. Integument densely microsculptured, matte, except on slightly shiny gaster. Abundant pubescence not obscuring integument texture. Head rectangular; vertex smooth and rounded, with two to three suberect hairs. Compound eyes large and ovoid located in upper half of face sides; ocelli normal. Mandibles triangular and slightly striated. Pilosity particularly present on outer face and on or near margins; long and posteriorly curved or J-shaped hairs in external margin particularly notable. Masticatory margin armed with 6 teeth; apical tooth largest and most pointed, preapical tooth of intermediate length, and remaining teeth small and irregular. Clypeus with ridge in centre and 7 stout setae along front edge; one pair of setae straddling posterior clypeus ridge. Posterior (basal) area of maxillae with six long and anteriorly curved Tab. 1: Measurements in millimetres of C. tartessica sp.n.

workers (n = 181).

Cataglyphis tartessica workers

or J-shaped hairs. Sparse pubescence on genae and ventral cephalic capsule. Pubescence more abundant in occipital area between and behind the eyes.

Mesosoma typical for this genus; propodeum evenly convex, long legs. Propodeal spiracle a long, narrow ellipse. Metapleural gland just above hind coxa; orifice protected by tuft of guard hairs. Scale-like petiole thick, with rounded apex. Sparse pubescence on mesonotum; abundant silver pubescence on pronotum, pleura, propodeum, petiole, and coxae.

Gaster shiny due to a very lightly microsculptured integument and very sparse pubescence. Apex of gaster with circular acidopore (nozzle-shaped) and fringed with setae. Long setae on gastral sternites; only sparse setae present on dorsal side of most apical tergites.

Description of paratype workers (Tab. 1, Fig. 1): Workers from different sampling locations showed morphometric variation. The biggest difference in body size occurred between workers from BRN and AZN populations ( ML: 2.13 ± 0.2 vs. 1.77 ± 0.11, n = 35, from nest 5, and n = 30, from nest 6, respectively). Workers also differed, generally, in their number of setae and mandibular teeth (5 - 7).

Tab. 2: Measurements in millimetres of Cataglyphis tartessica sp.n., brachypterous and ergatoid queens.

Description of queens (Tab. 2, Fig. 2): A notable feature of C. tartessica is the presence of two morphs of queens, brachypterous (short-winged queen) and ergatoid (wingless queen), which are described separately.

Description of brachypterous queens: Same body colouration as worker. but with bigger head, mesosoma, and gaster; head squarer, scape shorter. Compound eyes and ocelli normal. Strong, slightly striated mandibles; apical tooth more pointed and developed than in worker, other teeth small and short. Mesosoma (scutum, scutellum, and metanotum) less developed than those seen in species with macropterous queens, but very different from those of ergatoids and workers ( AMOR & al. 2011a). Short wings with weak venation; tegulae (scale-like sclerite covering forewing base) and wing stumps present and distinct. Legs shorter than those of ergatoids and workers ( FL: 1.64, 1.75 and 2.03 respectively). Scale-like petiole large and thick, with rounded apex. Gaster similar but larger than that of worker. Pubescence very sparse.

Variability: Little differences in mesonotum size and degree of thoracic development.

Description of ergatoids: Looks like a worker; hard to distinguish between the two using the naked eye. Scape length intermediate to those of brachypterous queens and worker. Mesosoma only slightly developed, with very small scutum, scutellum, and metanotum, in profile view appearing slightly elevated; scutum-scutellum suture very slightly impressed or disappeared. Metanotum plate arcuate and wrinkled. Wing insertion points extremely reduced ( Fig. 2). Leg length intermediate to those of brachypterous and worker.

Variability: At a glance, some ergatoids without wing insertion points; they can only be distinguished from workers by their physogastric abdomen and behaviour.

Description of males: External morphology (Tab. 3): Head, scape, mesosoma, petiole, and coxae dull black; funiculus, legs, and gaster dull amber. Large, light brown wings with strong venation.

Head ovoid and small. Prominent large ovoid compound eyes located in mid to upper half of face sides; prominent large ocelli also present. Cephalic capsule with a slight blister in the occipital margin behind the ocelli. Scoop-shaped mandibles, small, fragile, and without striations, that taper into a small apical tooth. Antennae with Tab. 3: Measurements in millimetres of males of Cata-

glyphis tartessica (n = 30).

Cataglyphis tartessica males (n = 30)

13 segments; the two basalmost funicular segments somewhat longer than the others.

Mesosoma massive, with well-developed scutum and scutellum; metanotum small. Pleural sclerites slightly striated next to wing insertions. Petiole scale-like, large, and thick, with bilobed or heart-shaped apex due to a slight, longitudinal constriction. Scutum, scutellum, and metanotum with very sparse pubescence. Scattered setae on scutum. Abundant pubescence on pronotum, propodeum, pleura, coxae, and petiole.

Gaster cylindrical densely microsculptured and with medium pubescence. Sternites with long and numerous setae, and tergites lacking setae.

Genital morphology ( Fig. 3): Paramere elongated and oval, with abundant long setae, and externally bearing a small finger-like process at its base next to cuspis. Volsella with digitus and cuspis straight and parallel, digitus larger than cuspis. Penisvalva twice as long as wide, with 7 (6 - 9) minute teeth in its internal arcuate margin, and a flat peak in its terminal end. Subgenital plate concave and bilobed posterolaterally, with rounded notch in centre of depression, at posterior margin; numerous setae present on its exterior face.

Variability: The extent of black colouration can vary among males; for example, the scape, which is usually black, can also be amber. The first funicular and gastral segments can be black in some males. The genitalia are very uniform; the number of penisvalva teeth can differ, and the posterior margin of the subgenital plate can be continuous (unbroken in the middle) or sometimes present a slight convexity.

Etymology: The name of this species comes from its current geographic distribution in southwestern Andalusia. It is distributed across the area thought to have been occupied by the ancient Tartessian civilisation, which existed three thousand years ago in the southwestern Iberian Peninsula (LÓPEZ-DAVALILLO 1999, GONZÁLEZ DE CANALES 2004).

Relationship to other Cataglyphis species: As previously noted, Cataglyphis tartessica sp.n. is phylogenetically closely related to C. floricola (see AMOR 2011), and belongs, as C. floricola (see TINAUT 1993), to the Cataglyphis emmae group (AGOSTI 1990). Apart from their different colouration, the two species are most notably distinguished by differences in the size of their brachypterous queens and males (brachypterous ML: 2.25 ± 0.16, n = 25 vs. 1.97 ± 0.08, n = 16, C. tartessica sp.n. – C. floricola , respectively; male ML: 2.63 ± 0.17, n = 29 vs. 2.20 ± 0.13, n = 23, C. tartessica – C. floricola , respectively. Student's t-test: t = 6.33 and t = 9.71, respectively; P <10- 6 in both cases; Fig. 4). Both species are ecologically very similar; they exhibit similar nesting and feeding preferences as well as comparable social structures and dispersal modes (F. Amor, unpubl.).

Natural history notes: Cataglyphis tartessica sp.n. is endemic to Spain. It occurs in habitats with sandy soils and has a small range. Its populations are located in southwestern Spain, in an arc of about 200 km around the lower stretch of the Guadalquivir River; its distribution is parapatric to that of C. floricola ( Fig. 5). The Guadalquivir river estuary underwent very strong changes throughout the Quaternary (SALVANY & CUSTODIO 1995, RODRÍGUEZ-RAMÍREZ & al. 1996, ZAZO & al. 2005, SALVANY & al. 2010); these changes may have generated barriers that resulted in isolation and speciation. Thus, the current parapatric distribution of the two taxa could be interpreted as their first meeting since the Quaternary: now that the barriers have disappeared, their ranges have spread. The apparent stable boundary between their populations – C. floricola occurs largely on the coast and C. tartessica sp.n. is found mostly inland – could be a consequence of each species being more fit under different ecological conditions.

Before the species' distributions were well characterised, Cataglyphis floricola (the black morph) was thought to occupy environments with more vegetative cover than C. tartessica sp.n. (previously identified as the C. floricola bicolour morph). Thus, the difference in their colouration was proposed to be related to different habitat preferences, which were linked to different environmental temperatures: Because C. floricola nested in areas characterised by lower temperatures, its colouration was black (CARPINTERO & al. 2002). However, current knowledge of their distribution patterns suggests that they do not prefer different levels of vegetative cover.

Cataglyphis tartessica sp.n. is a monomorphic, mediumsized ant (total body size: 4.51 ± 0.41 mm; n = 35), very similar in size and appearance to other Cataglyphis species of the southern Iberian Peninsula ( Fig. 6). The species is monodomous (each colony occupies one single nest) and monogynous (each colony is headed by a single queen), with a mean number of workers per nest of 182.8 ± 130.6 (n = 106). Although the species range is rather small, local nest density is high, with about 6 nests per 10 m 2 that are in close proximity to each other (0.81 ± 0.35; n = 202).

Colonies of C. tartessica sp.n. reproduce by fission. This process is described in detail by AMOR (2011). Around the summer solstice, a third of the workers and cocoons of a reproducing colony are transported, one by one, by a small number of "transporter" ants; the distance from the mother nest to the new nest is 8 m on average. The gynes are transported while still in their cocoons, and the queen of the colony remains in the mother nest. The presence in the same population of two queen morphs, brachypterous and ergatoid, that differ in reproductive potential (that of the brachypterous being greater) could be a consequence of a conflict of interest within the colony. So, ergatoids may compete with the brachypterous for the colony leadership and escape policing activity through their morphological similarity to the workers. Supernumerary gynes are reduced by worker aggression ( AMOR & al. 2011a).

The diet of C. tartessica sp.n. mainly consists of arthropod, which is typical of the Cataglyphis genus ( CERDÁ & al. 1989). However, the species, which is mostly a scavenger, also opportunistically harvests other available food resources, a characteristic that is an adaptation to resourcepoor environments. Thus, depending on location, we observe large differences in diet composition. Some diets contain a large quantity of plant material: in DBR in July, 80% of the diet consisted of Halimium halimifolium petals ( CERDÁ & al. 1992, 1996). Others demonstrate a clear preponderance of arthropod corpses where H. halimifolium is absent: in ALC, also in July, 90% of diet consisted of arthropod corpses ( AMOR 2011).

In Cataglyphis tartessica sp.n., foraging for food items is solitary, with individual ants searching for resources, as in all Cataglyphis species (WEHNER & al. 1983). However, although it is widely thought that the genus Cataglyphis has lost its ability to recruit as a result of selection imposed by high surface temperatures ( RUANO & al. 2000), the foragers of C. tartessica are able to carry out rudimentary but very efficient recruitment, without indicating the food location, when they find a large prey item near their nest. The result is cooperative prey-retrieval for large or heavy items that could not be exploited otherwise ( AMOR & al. 2010). A similar, short-distance recruitment behaviour, used to exploit rich food patches, has already been observed in C. bicolor (FABRICIUS, 1793) in Tunisia (WEHNER 1987: 33).