Saharo-Sindian buthid scorpions ; description of two new genera and species from Occidental Sahara and Afghanistan

Two new genera and species of Saharo-Sindian buthid scorpions are described on the basis of single specimens collected respectively in the deserts of Occidental Sahara and the North of Afghanistan. Th ese new scorpion taxa represent further endemic relicts in the Saharo-Sindian faunas. Comments are also included on the evolution of the desert regions of North Africa and the Middle East, as well as the possible consequences of these events on the distribution of the extant scorpion fauna.


Saharo-Sindian buthid scorpions; description of two new genera and species from
Occidental Sahara and Afghanistan Wilson R. Lourenço † , Bernard Duhem ‡

Introduction
As emphasised in recent publications (Qi and Lourenço 2007), scorpion diversity is particularly high in deserts and arid formations (Polis 1990).Th e scorpion fauna of North Africa, particularly the one specifi cally adapted to the Sahara desert has been the subject of intensive study, synthesised in the monographic work of Vachon (1952).Neverless, more detailed inventory work, and the revision of classical groups has revealed an increasing number of new species and even new genera.Th ese have been the subject of several recent publications (e. g.Lourenço 1998aLourenço , 1999aLourenço ,b, 2001aLourenço , 2002aLourenço , 2003Lourenço , 2005aLourenço , 2006;;Lourenço and Duhem 2007;Lourenço et al. 2003;Qi and Lourenço 2007).From these, it is apparent that knowledge of this fauna is still far from complete, and many other species, and probably genera too, await discovery.Moreover, the precise patterns of distribution of most taxa are yet only poorly understood.A similar assumption can be made about the fauna of the entire Palaearctic region since a great variety of scorpion genera inhabit the Middle East and Central Asia (Vachon 1958;Levy and Amitai 1980;Vachon and Kinzelbach 1987;Sissom 1990;Fet and Lowe 2000;Fet et al. 2003).
Th e desert areas of the Palaearctic region have been a rich source of speciation for several animal taxa (Kryzhanovsky 1965).It is assumed that extensive aridity during the Tertiary period in the southern Palaearctic region facilitated radiation among scorpions (Nenilin and Fet 1992;Fet 1994;Fet et al. 1998Fet et al. , 2003) ) as well as in other groups of organisms.Fet et al. (2001) drew particular attention to the diversity of psammophilic scorpions from the Palaearctic deserts of central and southern Asia.Th ese authors described a new genus and species of buthid scorpion from the Baluchistan Province of Iran, and presented a very complete table of characters for six buthid psammophilic genera, Anomalobuthus Kraepelin, 1900, Liobuthus Birula, 1898, Plesiobuthus Pocock, 1900, Psammobuthus Birula, 1911, Pectinibuthus Fet, 1984and Polisius Fet, Capes & Sissom, 2001.In parallel studies on scorpions from the Middle East, particularly those collected by the late Prof. Clas Naumann during his fi eld trips to Afghanistan in the early 1970s, have led to the description of several new taxa (e. g.Lourenço 1998bLourenço , 2001bLourenço , 2004aLourenço ,b, 2005b;;Lourenço and Huber 2000;Lourenço and Pézier 2002;Lourenço and Qi 2006a,b,c;Lourenço et al. 2002;Stathi and Lourenço 2003;Monod and Lourenço 2005).
It appears obvious that most of the scorpion genera found in the Saharo-Sindian domain are exclusively elements of the Sahara and/or Palaearctic deserts.Only two genera, Hottentotta Birula, 1908 andMesobuthus Vachon, 1950 contain species that are also found outside the arid zone of the Saharo-Sindian region.Moreover, diversity and species richness seem to reach a high degree at the extremities of the Saharo-Sindian region.Th is appears particularly true of the faunas of both Morocco-Occidental Sahara and Mauritania on the West and Afghanistan on the East.
Here we describe two new remarkable additions to the family Buthidae C. L. Koch, 1837.Th e fi rst, a new genus and species was collected by the late Prof. Pierre Louis Dekeyser in the region of Adrar-Sotuf, Occidental Sahara.Th is new genus shows affi nities with the genera Compsobuthus Vachon, 1949, Mesobuthus andSassanidotus Farzanpay, 1987.Th e last two genera, however, are absent from the fauna of North Africa.Th e second discovery is also of a new genus and species collected by the late Prof. Clas Naumann during fi eld trips to the North of Afghanistan.Th is new genus appears more of a 'puzzle' since it possesses characters seen in several buthid genera, especially, Odontobuthus Vachon, 1950, Mesobuthus, Hottentotta, Vachoniolus Levy, Amitai & Shulov, 1973and Buthus Leach, 1815.It is, perhaps, signifi cant that this last genus appears to be absent from Afghanistan.

Material and methods
Illustrations and measurements were made with the aid of a Wild M5 stereo-microscope with a drawing tube (camera lucida) and an ocular micrometer.Measurements follow Stahnke (1970) and are given in mm.Trichobothrial notations follow Vachon (1974) and morphological terminology mostly follows Vachon (1952) and Hjelle (1990).

Family Buthidae C. L. Koch, 1837
Genus Saharobuthus gen.n. urn:lsid:zoobank.org:act:66481881-9F12-4002-B8F4-8B49955F845B Diagnosis.Medium sized scorpions, 49.4 mm in total length (excluding telson).Coloration generally pale yellow with light reddish zones.Carapace with strongly marked and sculptured carinae; central median and posterior median carinae fused.Mesosoma tricarinate with strongly marked carinae.Dentate margins on fi xed and movable fi ngers of pedipalp chela composed of 11-12 oblique rows of granules; outer and inner accessory granules present on both fi ngers; four granules, two small and two large, located proximally to the terminal granule on the movable fi nger.Sternum triangular.Pectinal tooth count 28-29; fulcra present; basal middle lamellae not dilated.Chelicerae with one basal denticle on the fi xed fi nger; basal denticles of the movable fi nger reduced but not fused.Metasomal segment V with the anal arc composed of 10 ventral teeth and four rather uniform lateral lobes.Telson; vesicle pear-shaped with a long aculeus; subaculear tooth absent.Tarsi with two series of short spine-like setae.Trichobothrial pattern A-β (beta), orthobothriotaxy.
Derivatio nominis: after Sahara desert or Occidental Sahara region where the scorpion lives.
Type species Saharobuthus elegans sp.n.Affi nities of the new genus.Saharobuthus gen.n. shows affi nities with the genera Mesobuthus, Sassanidotus and Compsobuthus; however only the last named is also an element of the fauna of North Africa.Common characteristics are: moderate size, fusion of central median and posterior median carinae of carapace, absence of the formation of a 'lyra' confi guration and four granules located proximally to the terminal granule on the movable fi nger of chela.Th e new genus can, however, be distinguished from the other three genera by the shape of metasomal segment V and telson.In Saharobuthus gen.n., the ventromedian carinae are strongly marked, with lobate denticles; the anal arc is composed of 10 ventral teeth and four rather uniform lateral lobes.Telson vesicle shows a pear-like shape, and aculeus is much longer than vesicle.Th ese characteristics distinguish the new genus from Mesobuthus, Sassanidotus and in particular from Compsobuthus.Th e structure of metasomal segment V and telson recalls that found in the genus Leiurus Ehrenberg, 1828 and in the recently described genus Cicileiurus Teruel, 2007 from Morocco.In these two last genera, however, the presence of a 'lyra' confi guration is well established on the carapace carinae.Saharobuthus elegans sp.n. urn:lsid:zoobank.org:act:3C2F50F7-DD92-4854-8584-CBE4FF62B084Figs 1, 9-15, 30 Diagnosis: as for the new genus.
Etymology: Th e specifi c name is a reference to the very slender build of the new species.
Description based on the male holotype (Measurements in Table 1).
Coloration.Basically yellowish to pale yellow, with some light reddish zones.Prosoma: carapace yellowish with carinae and granulations reddish; median and lateral eyes surrounded by black pigment.Mesosoma: yellowish with some very light greyish zones.Metasoma: all segments yellowish, with carinae reddish.Vesicle pale yellow; base of aculeus yellowish with a reddish tip.Venter yellowish; pectines pale yellow.Chelicerae yellowish without spots; fi ngers yellowish with reddish teeth.Pedipalps yellowish with carinae slightly reddish; rows of granules on fi ngers reddish.Legs yellowish with some diff used spots.
Morphology.Prosoma: Anterior margin of carapace not emarginated, almost straight.Carapace carinae strongly developed; anterior median, central median and posterior median carinae strongly marked; central median and posterior median fused; central lateral strongly marked; posterior median carinae terminating distally in a small spinoid process that extends slightly beyond the posterior margin of the carapace (process less marked than in the genus Compsobuthus).Intercarinal spaces strongly granular on anterior and posterior zones; moderate to weak on the other regions.Median ocular tubercle anterior to the centre of the carapace; median eyes separated by two ocular diameters.Th ree pairs of lateral eyes.Mesosoma: Tergites I-VI tricarinate.Lateral carinae on I-VI strongly marked; each carina terminating distally with a spinoid process that extends slightly beyond the posterior margin of the tergite.Median carinae on I moderate; on II-VI strong, crenulate; terminating distally on each segment with a spinoid process that also extends slightly beyond the posterior margin of the tergite.Tergite VII pentacarinate, with lateral pairs of carinae strong; median carinae present on proximal half, strong.Intercarinal spaces strongly granular.Sternites: Lateral carinae absent from sternites III to VI; moderate, fi nely crenulate on VII.Submedian carinae on sternites III-VI absent; on VII moderate.Pectines long; pectinal tooth count 28-29.Metasoma: Segments I-II with 10 carinae, crenulate; III-IV with 8 carinae.Segment V with 5 carinae; ventromedian carinae strongly marked, with several lobate denticles; anal arc  aculeus longer than vesicle; subaculear tooth absent.Chelicerae with two reduced but not fused denticles at the base of the movable fi nger (Vachon, 1963).Pedipalps: Trichobothrial pattern orthobothriotaxic, type A (Vachon, 1974); dorsal trichobothria of femur in β (beta) confi guration (Vachon, 1975) Type species Pantobuthus complicatus sp.n.Affi nities of the new genus.Th e new genus Pantobuthus shows affi nities with several genera, such as Odontobuthus, Buthus, Mesobuthus, Hottentotta and Vachoniolus, which are also elements of the North African and Palaearctic faunas.Th e moderately marked carapace carinae which form only an incomplete 'lyra' confi guration associates the new genus to Hottentotta and Mesobuthus, but metasomal segments II to IV with strong spinoid granules on the ventral carinae, are more similar to those of the genus Odontobuthus.Th e very central position of the median ocular tubercle on the carapace and the shape of the telson with a strongly globular vesicle and a very short aculeus associates Pantobuthus gen.n. with Buthus.In this last genus, however, both carapace and mesosomal carinae are strongly developed and the 'lyra' confi guration is totally complete.Th e very short and bulky pedipalps again associate Pantobuthus gen.n. with Buthus.However, the very strongly globular chela recall those of the male Vachoniolus.Th e male of Pantobuthus complicatus sp.n. remains unknown.Finally, the total displacement of chela trichobothrium db to the internal surface of fi xed fi nger, the retreated position of lateral eyes and the tarsi with two series of short spine-like setae, but with external series reduced or totally absent appear to be particular characteristics of this genus.Etymology: Th e specifi c name (from Latin complicare) means 'consisting of parts intricately combined' in reference to the puzzling characteristics of the new species.

Pantobuthus complicatus
Description based on female holotype (Measurements in Table 1).
Coloration.Basically yellowish with some light grey zones.Prosoma: carapace yellowish, paler anteriorly; carinae slightly reddish; eyes marked by dark to blackish pigment.Mesosoma: yellowish with tergites marked with greyish confl uent zones; only the median carinae are dark.Metasoma: segments I to V yellowish with reddish carinae; vesicle yellowish with vestigial reddish zones laterally; aculeus yellowish at the base and dark reddish at its extremity.Venter yellowish; pectines pale yellow.Chelicerae yellowish without any variegated spots; fi ngers yellowish with reddish teeth.Pedipalps: yellowish with carinae reddish; chela fi ngers with the oblique rows of granules reddish.Legs pale yellow.
Morphology.Carapace moderately granular; anterior margin with a very weak median concavity, almost straight.Carinae moderately marked; anterior median strongly granular, central median and posterior median carinae moderately granular, with a moderately to weakly marked 'lyre' confi guration.All furrows moderate.Median ocular tubercle at the centre of carapace.Eyes separated by more than two ocular diameters.Th ree pairs of lateral eyes situated in a posterior position in relation to the anterior edge; the fi rst two of moderate size, the last vestigial.Sternum triangular and short; wider than long.Mesosoma: tergites moderately granular.Th ree longitudinal carinae weakly crenulate in tergites I to VI; lateral carinae reduced in tergites I to III.Tergite VII pentacarinate.Venter: genital operculum divided longitudinally in two semi-oval plates.Pectines: pectinal tooth count 24-23; middle basal lamella of the pectines not dilated.Sternites without granules, smooth with elongated spiracles; four carinae on  sternite VII; other sternites acarinated and with two vestigial furrows.Metasoma: segments I to III with 10 crenulated carinae; segment IV with 8 crenulated carinae; ventral carinae strongly marked on segments II to IV with lobate denticles; the fi rst four segments with a smooth dorsal depression; segment V with fi ve carinae; the lateroventral carinae crenulate with 2-3 lobate denticles posteriorly; the most posterior very large; ventral median carina slightly divided posteriorly; anal arc composed of 7-8 ventral teeth, and two lateral lobes.Intercarinal spaces moderately granular.Telson with a strongly globular vesicle and some granulations on the lateral and ventral surfaces; aculeus curved and much shorter than the vesicle, without a subaculear tooth.Cheliceral dentition as defi ned by Vachon (1963) for the family Buthidae; external distal and internal distal teeth approximately the same length; basal teeth on movable fi nger small but not fused; ventral aspect of both fi ngers and manus covered with long dense setae.Pedipalps: femur pentacarinate; patella with 7-8 carinae; chela with only vestigial carinae; all faces weakly granular.Fixed and movable fi ngers with 9-10 oblique rows of granules.Internal and external accessory granules present, strong; three accessory granules on the distal end of the movable fi nger next to the terminal denticle.Legs: tarsi with two series of short spine-like setae; internal series with 5-7 setae, external reduced to 1-3 setae or totally absent; tibial spur strong on legs III and IV; pedal spurs moderate to strong on legs I to IV. Trichobothriotaxy: trichobothrial pattern of Type A, orthobothriotaxic as defi ned by Vachon (1974).Dorsal trichobothria of femur arranged in β (beta) confi guration (Vachon, 1975).Trichobothrium db of chela totally displaced over the internal face of fi xed fi nger.

Distribution of related genera: Odontobuthus, Mesobuthus, Hottentotta, Compsobuthus, Buthus, Leiurus and Vachoniolus
Th e genus Odontobuthus probably has a distribution limited to the central and northwestern regions of Iran, to Pakistan and India.Its presence in Iraq was only recently confi rmed with the description of Odontobuthus bidentatus Lourenço & Pézier, 2002.Th e diff erent localities indicated for O. bidentatus, correspond closely with the pattern of distribution already observed by Sissom and Fet (1998), for Compsobuthus matthiesseni (Birula, 1905).Th is species is widely distributed within the drainage systems of the Tigris and Euphrates Rivers.Such a pattern of distribution applies in sites where the altitude ranges on average from 150 to 200 m.In contrast, at the sites where Odontobuthus doriae (Th orell, 1876) was collected, the altitude is much greater, ranging on average from 1000 to 3000 m.
In their study of the genus Buthotus (= Hottentotta), Vachon and Stockmann (1968) recognized and defi ned several lineages and sub-lineages of Hottentotta.Both authors, as well as Vachon and Kinzelbach (1987), suggested that the African, Saharo-Sindian and Indian lineages might be diff erent.In fact, several species originally thought to belong to the Indian lineage are currently placed in the genus Mesobuthus which is distributed from the Balkans to China (see also Tikader and Bastawade 1983).Fet and Lowe (2000) pointed out that the relationships of Mesobuthus to other genera, and in particular to Hottentotta remain poorly defi ned.According to V. Fet (personal communication), the clarifi cation of this situation will require a careful analysis of clusters of 'true' Mesobuthus versus African and Middle-East Hottentotta, with the possible defi nition of new characters.Th e DNA tree proposed by Fet et al. (2003) shows that Mesobuthus is much closer to Compsobuthus than it is to Hottentotta, but in this study only few Hottentotta species were analysed.
Compsobuthus is very diverse and widely distributed from Mauritania to India.On the other hand, Mesobuthus is also widely distributed but with a centre of its diversity in Iran and Central Asia.Phylogenetic studies on the genus Mesobuthus (Gantenbein et al. 2003), indicate that western Palaearctic forms of this genus may be ancestral, and forms distributed further east and north in Central Asia, Mongolia and China are derived from them.Th e modern range of the genus Mesobuthus represents the northern limit of scorpion distribution in Asia (Gromov 2001).Th is corresponds to the general trend in the evolution of Central Asian desert biota (Kryzhanovsky 1965;Fet 1994).
Buthus, is widespread over the Saharo-Sindian region, whereas Leiurus has a more centralized distribution.Th e same is true of the psammophile Vachoniolus.All are typical elements of the Palaearctic deserts in North Africa and the Middle East (Vachon 1952;Levy and Amitai 1980;Sissom 1994;Lourenço 2003;2005a).Several results suggest that Leiurus may be more closely related to Androctonus Ehrenberg, 1828 than to any other genus represented in Saharo-Sindian region (Fet et al. 2003).Th is is consistent with the data on the toxins of their venoms (Loret and Hammock 2001).

Biogeographical considerations on the Saharo-Sindian scorpion fauna
Th e present composition of the Saharo-Sindian fauna is, in fact, the heritage of ancient faunas present in North Africa and the Palaearctic region since the beginning of or, at least, Middle Cenozoic times (Vachon 1952(Vachon , 1958)).North Africa and the Palaearctic region have experienced numerous paleoclimatological vicissitudes during the last few million years, some even in more or less recent Quaternary periods.Th e Sahara, for example, has undergone a series of wet periods, the most recent occurring 10.000-5000 years BP, and it was not until about 3000 years BP that the Sahara assumed its present arid state (Cloudsley-Th ompson 1984).Even though recent studies suggest that the Sahara desert may be much older than was previously thought (Schuster et al. 2006), it seems reasonable to postulate that extremely arid areas have always existed as patchy desert enclaves, even when the general climate of North Africa enjoyed more mesic conditions.
In these arid and desert regions of both the North African Sahara and the Palaearctic region, a specialized scorpion fauna would have evolved in response to the aridity.Th ese 'ancient lineages' adapted to arid conditions, undoubtedly correspond with extant groups such as genera Androctonus, Buthacus Birula, 1908, Buthiscus Birula, 1905, Buthus, and Leiurus some of which are typically psammophilic.It is important to emphasise the fact that these lineages must have been present in North Africa for at least 10 to 15 MY (Gantenbein and Largiadèr 2003;Lourenço and Vachon 2004), and also in the Palaearctic re-gion during subsequent periods (Vachon 1958).In contrast, other lineages less well adapted to aridity and, previously, only present in more mesic environments, have regressed markedly in their distribution with the expansion of the desert.In consequence they have, in some cases, already experienced negative selection and doubtless will eventually disappear.In other cases, populations have been reduced to very limited and patchy zones of distribution, sometimes with remarkable disjunctions in their patterns of distribution.
Th e patterns in the distribution of North African scorpions observed today can be summarised as follows: A core Saharian region, which was described by Vachon (1952) as the 'central compartment', in which only the groups best adapted to xeric conditions (such as the genera Androctonus, Buthacus, Buthiscus, Buthus, and Leiurus) are distributed.In the peri-Saharian zone, surrounding most of the central compartment, some remarkable disjunctions occur.One of them is presented by the genus Microbuthus Kraepelin, 1898 with two species in Mauritania and Morocco in the West and three other species in Eritrea, Djibouti and Egypt in the East (Lourenço, 2002b;Lourenço & Duhem, 2007).Finally, as indicated by Vachon (1952), several groups (sometimes less well adapted to xeric environments) have their populations limited to refugia.Th ese are represented by the Saharan massifs, such as Hoggar, Aïr and Adrar, as well as other elevated regions in Mauritania and Occidental Sahara.Some of the endemic genera, such as Cicileus Vachon, 1948, Lissothus Vachon, 1948, Egyptobuthus Lourenço, 1999, and Pseudolissothus Lourenço, 2001 provide useful examples (Vachon 1952;Lourenço 1999aLourenço ,b, 2001a)).Th e same picture can be observed in several regions of the Middle East, in particular among the mountain ranges of Iran and Afghanistan (Vachon 1958;Vachon and Kinzelbach 1987).Th e new genera and species described here probably correspond to this type of endemic and relictual pattern of distribution.

Table 1 .
Morphometric values (in mm) of the male holotype of Saharobuthus elegans sp.n., and the female holotype of Pantobuthus complicatus sp.n.
. Femur pentacarinate; carinae strongly crenulate.Patella with eight carinae, moderate; dorsointernal carinae with 2-3 spinoid granules.Chela short with moderately elongated fi ngers; all carinae vestigial.Dentate margins on movable and fi xed fi ngers composed of 11-12 oblique rows of granules; outer and inner accessory granules present on both fi ngers; four granules, two small and two large, located proximally to the terminal granule on the movable fi nger; basal region of movable fi nger with a strong lobe.Legs: Ventral aspect of tarsi with two series of spine-like setae.Tibial spurs present on legs III and IV, strongly marked.Pedal spurs present on all legs, moderate to strongly marked.Geographic distribution.Only known from the type locality.
Genus Pantobuthus gen.n.urn:lsid:zoobank.org:act:3C2F50F7-DD92-4854-8584-CBE4FF62B084Diagnosis.Large scorpions, 66.3 mm in total length (excluding telson).Coloration generally pale yellow with regions of very light grey.Carapace carinae moderately marked; 'lyra' confi guration rather incomplete; median ocular tubercle at the centre of carapace; three pairs of lateral eyes situated in a posterior position in relation to the anterior edge; third pair totally vestigial.Sternum triangular, wider than long.Pedipalps very short and bulky; chela strongly globular; dentate margins on fi xed and movable fi ngers of pedipalp chela composed of 9-10 oblique rows of granules.Outer and inner accessory granules present on both fi ngers, strongly marked.Pectinal tooth count 24-23; fulcra present; basal middle lamellae not dilated.Chelicerae with one basal denticle on the fi xed fi nger; basal denticles of the movable fi nger strongly reduced.Metasomal segments II to IV with strong spinoid granules on ventral carinae; telson with a strongly globular vesicle; aculeus much shorter than vesicle and strongly curved; subaculear tooth absent.