A New Ant Species , Temnothorax ansei sp . n . ( Hymenoptera : Formicidae ) from the Arid Environments of South-eastern Spain

Temnothorax (Mayr, 1861), is a speciose genus of small and generally inconspicuous ant with a predominantly Holartic distribution. The most recent catalogue lists 380 valid species and 47 valid subspecies (Bolton, 2015). Colonies are typically small, often with less than 100 workers (Prebus, 2015). Temnothorax is divided into nine species groups (Cagniant & Espadaler, 1997). One of those is laurae species group, whose members are characterized by large eyes relative to the length of the head capsule (OI>30), postpetiole more or less trapezoidal in dorsal view (Prebus, 2015), long and erect hairs on alitrunk, petiole and postpetiole, rectangular head, and the presence of metanotal groove (Tinaut, 1994; Cagniant & Espadaler, 1997). They are rarely collected, probably because of their small colony size and nocturnal activity patterns; caused by hot and arid environment they inhabit (Tinaut, 1994; Cagniant & Espadaler, 1997). Abstract We describe here a new ant species in the genus Temnothorax, species group laurae, based on morphological evidence supported by other biological information. It has been discovered at two locations in southeast Spain: Pulpí (Almería) and Lorca (Murcia). This species is a member of the laurae species group based on the following characters: large eyes, long and erect hairs on alitrunk, petiole and postpetiole, rectangular head and metanotal groove. Other characters unique to new species are: dark brown in color, decumbent pilosity, and smooth and shiny head and pronotum. In addition, this new species is distinctly nocturnal in its activity patterns. Based on the morphological measurements of the queens and the workers, as well as our observations in the laboratory, we predict that this species has a dependent colony founding. An identification key to the Iberian Peninsula species of the laurae group is also provided. Sociobiology An international journal on social insects


Introduction
Temnothorax (Mayr, 1861), is a speciose genus of small and generally inconspicuous ant with a predominantly Holartic distribution.The most recent catalogue lists 380 valid species and 47 valid subspecies (Bolton, 2015).Colonies are typically small, often with less than 100 workers (Prebus, 2015).Temnothorax is divided into nine species groups (Cagniant & Espadaler, 1997).One of those is laurae species group, whose members are characterized by large eyes relative to the length of the head capsule (OI>30), postpetiole more or less trapezoidal in dorsal view (Prebus, 2015), long and erect hairs on alitrunk, petiole and postpetiole, rectangular head, and In the Iberian Peninsula, there are five known species belonging to the laurae group: Temnothorax blascoi (Espadaler, 1996), T. caesari (Espadaler, 1997b), T. crepuscularis (Tinaut, 1994), T. universitatis (Espadaler, 1997a) and T. naeviventris (Santschi, 1910).Two of these are present in the Segura river basin (south-east Spain): T. blascoi (Catarineu & Tinaut, 2012) and T. universitatis (see Table 2).Considering the difficulty of detecting individuals in this group, it is likely there are more undescribed species.
On July of 2014, in a pitfall transect, we collected two workers of a Temnothorax species, belonging to the laurae group, that we were unable to identify, at a location near Pulpí (Almería, Andalucía, Spain) 1.716W, 37.389N (decimal format).The same species was also collected in two pitfall transects in Lorca (Murcia, Spain) 1.774W, 37.670N and 1.774W, 37. 685N (Fig 1).

RESEARCH ARTICLE -ANTS
Pulpí site obtaining five living colonies.We were able to keep three of these colonies in the laboratory until males and queens were acquired.

Material and methods
Digital color images were obtained by AntWeb and are available online (Fisher, 2002; http://www.antweb.org).Measurements were taken of 27 workers, eight queens and five males with a stereo microscope Leica S6D at a micrometer magnification of up to x80.Morphometric characters and indices are based on Seifert et al. (2014), Prebus (2015), and Seifert & Csősz (2015): BI. Buschinger Index: SPST/ SPL.CS.Cephalic size: the arithmetic mean of HL and HW EL.Eye Length: maximum diameter of compound eye, including all structural visible ommatidia irrespective of the pigmentation status, measured in oblique lateral view.
HL. Head Length: maximum distance from the midpoint of the anterior clypeal margin to the mid-point of the posterior margin of head, measured in full-face view.
HW. Head Width: width of head directly behind the eyes, measured in full-face view.
OI. Ocular Index: EL/HW x 100.SPL.Minimum distance between the center of the propodeal spiracle and the margin of subspinal excavation, measured with both end points positioned in the same focal level.
SPST.Distance between the center of the propodeal stigma and the spine tip, the stigma center refers to the midpoint defined by the outer cuticular ring but not to the center of the real stigma opening that may be positioned eccentrically.
TL. Tibia Length: maximum length of the tibia.WL.Weber's Length: diagonal length of mesosoma in lateral view from the posteroventral margin of propodeal lobe to the anterior-most point of pronotal slope, excluding the neck.
The varying degrees of inclination of pubescence and pilosity are often of high diagnostic value throughout a broad spectrum of ant genera.In this context, we use the terms "erect", "suberect", "subdecumbent", "decumbent", and "appressed" following Wilson (1955).

Repositories
The National Museum of Natural Sciences (MNCN, Madrid, Spain) holotype, two workers, one queen and one male (registration number C.T. 2730).The California Academy of Sciences, USA, two workers, one intermorph, one queen and one male (CASENT0763773, CASENT0763775, CASENT 0919826, CASENT0919953 and CASENT 0919954).The Natural History Museum, London, U.K., two workers, one queen and one male.Museum d'Histoire Naturelle, Genève, Switzerland, two workers, one queen and one male (MHNG ENTO numbers 10129 to 10132).University of Granada, Spain, two workers, one queen and one male.Coll.Xavier Espadaler (Autonomous University of Barcelona, Spain) two workers, one queen and one male.Coll.Joaquin L. Reyes-López (University of Cordoba, Spain) eight workers, three queens, one intermorph and one male.Coll.Chema Catarineu (Murcia, Spain) 11 workers, five queen, one intermorph and three male.Size and color as in workers.Hairs on alitrunk, petiole and postpetiole long and erect (mean mesonotum hair length=78µm).Eyes large (EL/CS=0.31-0.37),ocelli well developed.Antennae 12-segmented.Antennal scape reaching occiput.Antennal club three-segmented, funiculus concolorous.Mesosoma only slightly bigger than in workers.Anterior edges of pronotum slightly visible from the dorsal view.Pronotum, scutum and scutellum smooth and shiny.Mesopleurae with a few lateral costulae.Propodeum with lateral costulae, smooth and shiny between the spines.Petiolar node triangular in profile, its apex more acute than in workers.Well developed spines but somewhat smaller than in workers (SPST/CS=0.32-0.39).Petiole, postpetiole and gaster as in workers.Transparent wings, with very reduced veins.Pterostigma transparent, light yellow.
Variability: propodeal spines can vary in size, apex of petiole varies from less to more rounded.

Description of male
Head, alitrunk, petiole, postpetiole and gaster light brown; antennae and legs lighter.Hairs on alitrunk, petiole and postpetiole long and erect (mean mesonotum hair length = 84µm).Oval-shaped head, smooth and shiny.Very large eyes (EL/CS=0.42-0.46),nearly half of head length, located in the lower half of face sides.Ocelli well developed.Antennae 13-segmented.Scape surpassing the occipital margin and as long as the first 8 segments of the funiculus.Antennal club four-segmented.Mandibles with one apical tooth, one subapical and 2-3 smaller.Mesopleaurae and propodeum smooth, with less prominent costulae than in worker and queen.Pronotum, prescutum, scutum and scutellum smooth and shiny.Notauli marked.Scutum and scutellum separated by a depression.Metanotum present, narrow and separated from scutellum and propodeum.Propodeum reticulated, with some lateral costulae

Etymology
The species recognizes and honours the Asociación de Naturalistas del Sureste (ANSE), an organization rooted in the south-east of Spain since 1973 (ANSE 2015).This is a naturalist and environmentalist, non-governmental organization which, by its efforts on nature research, awareness, and conservation activism, has earned the respect and support of generations of scientists and citizens.Most significantly, for the last five decades, ANSE has been a force of scientific and environmental activism promoting the formal recognition of the previously poorly-valued semiarid ecosystems of the south-east of Spain, where T. ansei, our newly discovered species, finds its home.

Biology
Foraging workers of T. ansei sp.n. were attracted to the baits at night, or sometimes during twilight (in June and July, the workers begin to forage from approximately about 19:00 GMT).After feeding for a few minutes, they carried a small cookie crumb to their nearby nest, although never more than one meter away.Through careful monitoring in a territory of about 230 m 2 , we were able to locate five nests, each with a single entrance hole in the soil of approximately 1 mm in diameter.These nests were very hard to detect as they lacked any external signs or evidence of ant activity.
We excavated the five nests and found that the main chamber was about 15-20 cm deep.Colonies ranged from two to 52 workers.Two of them had two wingless queens (Table 1).Three of these colonies were relocated to our laboratory and have been maintained there under controlled conditions to date.The other two, an incipient colony with only two workers and other with 13, did not survive in captivity.Ants were fed with honey-water and small crickets and have produced during two years new males and females.These sexuals were born from eggs laid by the queen in the laboratory.All 19 queens born in captivity lost their wings in the first 1-4 weeks, 13 of them in the first three days, and then continued living normally in the nest, cooperating with the others.This behaviour has also been observed in other species of the group, for instance T. caesari (Espadaler, 1997b).Eggs, larvae and pupae were placed by the workers in one group on the floor of one chamber altogether.sp.n. in the laurae group is species T. universitatis.We can differentiate between those two species because T. universitatis worker is light brown or dirty yellow, with head less shiny, alitrunk dorsally opaque and pronotum laterally rugulose.
From the other Iberian species in the laurae group, the main differences are: Temnothorax blascoi is smaller, light yellow, with dense pilosity all over the body and with long and thin setae similar to Temnothorax recedens Espadaler.
Temnothorax caesari has mesosoma olivaceus brown, less shinning and less quadrangular head.Dorsal striae in pronotum and mesonotum.Pilosity erect on head and gaster.
Temnothorax crepuscularis is yellow, with metanotal groove unmarked, abundant semi-erect setae on head and gaster, head and alitrunk rough, petiole and postpetiole dorsally rough.
Temnothorax naeviventris is light yellow, with head and alitrunk coarse and and with pilosity erect in head.
Based on our original findings and the prior contributions by other authors (Santschi, 1910;Tinaut, 1994;Espadaler 1996Espadaler , 1997aEspadaler , 1997b)), we propose the following dichotomous key to the Iberian laurae group species.This key is based on the external morphology of the workers: Key to the worker caste of Iberian Temnothorax, laurae species group "Pulpí"

Biological observations
Ants show two contrasting strategies of colony founding.In the Independent Colony Foundation (ICF), a queen can raise the first generation of brood alone.The ICF strategy frequently involves claustral founding where queens are characterized by voluminous wing muscles which can histolize after dispersal.These queens must also have high metabolic reserves.In contrast, Dependent Colony Foundation (DCF), is a strategy in which the queen is helped by some workers to create a new colony-budding or fission (Hölldobler & Wilson, 1990;Heinze & Tsuji, 1995;Peeters & Ito, 2001;Keller et al., 2014).
In a majority of species, mating and dispersals take place during a nuptial flight.There is always a trade off

Ecology
Both collecting localities are semiarid habitats with sparse vegetation cover, dominated by Stipa tenacissima L. grassland at the Pulpí site and chamaephytes and little shrubs at the Lorca site.Altitudes are 243 m at Pulpí and 464-591 m at Lorca.The average annual rainfall is 272 and 313 mm at Pulpí and Lorca sites, respectively.
We found 25 ant species at the same habitat (Table 2), including T. universitatis, a species we consider, based on the morphology, to be the closest relative of T. ansei sp.n.

Taxonomic position and diagnosis
This new species, T. ansei sp.n.clearly belongs to the laurae group, by showing characteristic features of this group such as large eyes in relation to the length of the head capsule (OI > 30).Additional traits consistent with the laurae group are head capsule elongated (CI < 85), postpetiole more or less trapezoidal in dorsal view and widest anterior to the midlength of the segment (Prebus, 2015).As many species within this group, T. ansei sp.n. is also found in arid environments.
Based on the morphology, the closest relative of T. ansei between the costs and benefits of flight.Wing reduction or simplified thoracic structures could be some of the steps associated with the shift in mating and dispersal strategies from nuptial flight and ICF to DCF (Tinaut & Heinze, 1992).
In the past, DCF has been linked with a range of ecological factors, for example habitat patchiness, nest site limitation, food limitation, competition, predation, climate, or nest site instability (Heinze & Tsuji, 1995;Cronin et al., 2013).Several studies suggested also a correlation between the loss of flight capability in sexually active females and the ecological conditions in arid and semi-arid environments (Tinaut & Heinze, 1992;Tinaut, 1994;Heinze & Tsuji, 1995).Unsurprisingly, at least 5 to 8 % of all ant species from Spain or Algeria produce queens incapable of dispersal and mating flights (Tinaut & Heinze, 1992).
In the polymorphic queen of T. longispinosus (Roger), dependent-founding queens are smaller than independentfounding queens and exhibited significantly lower flight activity.This reduced flight activity may facilitate returning to the natal nest after mating (Howard & Kennedy, 2007).Our data show that in T. ansei sp.n., queens are small and similar to the size of workers.The queen/worker volume has been related to nest founding strategies, independent or dependent (Stille, 1996).For T. ansei, this ratio is 1,91 (five workers and five queens from the same locality) and this fits with the dependent foundation (ratio 1.9-2.7),being very far from independent foundation range (ratio 5.1-9.1).
In T. ansei sp.n., we found that queens lost their wings within the nest.Espadaler (1997b), studying T. caesari, found that seven out of seven queens born in the laboratory lost their wings within two days, and without being fertilized.It is known that the queens that disperse by mating flights do not lose their wings inside the colony (Hölldobler & Wilson, 1990;Heinze & Tsuji, 1995), and the rapid loss of wings in females seems to indicate intranidal mating (Heinze & Tsuji, 1995).Furthermore, T. ansei sp.n.seems to be partially polygynous, both in the wild and in the laboratory.Two out of five nests excavated have had two wingless queens, and in the laboratory the three colonies nowadays have seven, six and two wingless queens respectively but this could be caused by laboratory conditions.Finally, we have found three worker-queen intermorphs (with our current data, the ratio intermorphs/workers is 3/32).
Our data shows that the T. ansei sp.n.colony founding strategy is likely to be Dependent Colony Foundation.Further research is needed to examine the mating behaviour and to confirm the colony founding strategy of this new species.

Fig 1 .
Fig 1. Map of Spain with the location of the Segura river basin outlined and the two localities with Temnothorax ansei sp.n.indicated with black squares.

Table 1 .
Temnothorax ansei sp.n.male wings.Photo credit: Michele Esposito, from www.AntWeb.org,CASENT0919954_P_2,published with permission.Nest excavations data for the new species Temnothorax ansei sp.n., discovered in 2014 in the south-east of Spain.