Androctonus ajjer, Ythier & Sadine & Alioua & Lourenço, 2025

Ythier, Eric, Sadine, Salah Eddine, Alioua, Youcef & Lourenço, Wilson R., 2025, A new species of Androctonus Ehrenberg, 1828 from the Tassili n'Ajjer, Algeria (Scorpiones: Buthidae), Faunitaxys 13 (8), pp. 1-8 : 2-5

Androctonus ajjer sp. n.

( Fig. 1-10)

ZooBank:https://zoobank.org/ D740E1BF-147C-4F1F-BCD3-7072EC5225A7

Holotype, ♂, Algeria, Djanet Wilaya , Eferi, foothills of the Tassili n’Ajjer, 1010 m a.s.l., 42°29'N - 009°29'E, 09/XI/2022 (Y. Alioua). Type material deposited in the collections of the Muséum national d’Histoire naturelle, Paris, France.

Etymology. – The specific name is placed in apposition to the generic name and refers to Tassili n’Ajjer (Tassili of the Kel Ajjer Tuareg confederation), where the new species was collected.

Diagnosis. – Scorpion of large size for the genus, with a total length of 87.26 mm for the male holotype. General coloration yellowish to brownish yellow; metasomal segments IV-V and telson with dark pigmentation; legs pale yellow. Metasomal segments I-IV of approximately the same width, with a moderately to strongly marked dorsal depression; dorsal carinae strongly marked with granules becoming spinoid posteriorly; segments III-IV with one bigger posterior spinoid granule.Anal arc composed of 14 ventral teeth and four lateral lobes. Fixed and movable fingers with 12 rows of granules. Leg retrolateral basitarsal spurs with basal tooth simple. Pectines with 31-33 teeth in male holotype; fulcra with 6-7 macrosetae externally and one microseta internally.

Description based on male holotype (morphometric measurements after the description)

Coloration (in alcohol). – Basically, yellowish to brownish yellow. Prosoma: carapace yellowish orange; eyes marked with dark pigment. Mesosoma yellowish orange without spots; carinae not pigmented. Metasomal segments I-III yellowish to yellowish orange, IV-V yellowish orange with brownish (IV) to dark brown (V) pigmentation; carinae pigmented from II-V, especially ventrally;telson vesicle yellowish with dark brown pigmentation, aculeus yellowish orange at its base and blackish at its extremity. Venter yellowish; genital operculum and pectines paler than the other zones. Chelicerae yellowish without any spots; fingers yellowish with dark red teeth. Pedipalps yellowish orange; fingers with the oblique rows of granules dark red. Legs pale yellow without spots.

Morphology. – Carapace moderately granular; anterior margin almost straight, slightly concave. Carinae moderately to strongly marked; anterior median, central median and posterior median carinae strongly granular, other carinae moderately granular.All furrows weak. Median ocular tubercle located slightly anterior to the centre of the carapace; eyes separated by about three ocular diameters; five pairs of lateral eyes, the first three of moderate size, the last two reduced.Sternum triangularandnarrow,longer thanwide. Mesosoma : tergites moderately granular.Three longitudinal carinae moderately crenulate on tergites I to VI; tergite VII pentacarinate with carinae moderately to strongly crenulate. Venter: genital operculum divided longitudinally, each plate with an oval shape. Pectines:pectinal tooth count 31-33 in male holotype;middle basal lamella of the pectines not dilated; fulcra with 6-7 macrosetae externally, one microseta internally. Sternites III-VI with elongated spiracles, almost smooth with only some minute granules laterally; sternites III-V acarinate, VI with four vestigial carinae; sternite VII with four moderate carinae and minute granulation on whole surface except between central carinae. Metasomal segments I-IV of approximately the same width (not enlarged posteriorly), with a smooth and moderately to strongly marked dorsal depression; segment I with ten complete carinae, crenulated; segments II to IV with eight complete carinae, strongly crenulated;lateral inframedian carinae represented by 10-12 granules on distal two thirds of segment II, by 2-3 granules on III, absent on IV; dorsal carinae strongly marked with granules becoming spinoid posteriorly, segments III-IV with one bigger posterior spinoid granule; segment V with five carinae; the latero-ventral carinae strongly crenulate with several lobate denticles; ventral median carinae not divided posteriorly; anal arc composed of 14 ventral teeth and with four lateral lobes; all metasomal segments with intercarinal spaces slightly granular to smooth and a weak setation. Telson with some moderate granulations ventrally;aculeus moderately curved and of about same size as the vesicle, withouta subaculear tubercle.Cheliceraldentitionas defined by Vachon (1963) for the family Buthidae ; external distal and internal distal teeth approximately the same length; ventral aspect of both fingers and manus covered with long dense setae. Pedipalps with a weak setation; femur pentacarinate;patella with 7carinaebutonlydorso-internal andinternalare well marked;other carinaeare weak to vestigial;chela withvestigialcarinae;all faces very weakly granular to smooth; fixed and movable fingers with 12 rows of granules, internal and external accessory granules present, strong; two accessory granules on the distal end of the movable finger next to the terminal denticle; scalloping of the proximal dentate margin of fixed finger in male. Legs: tarsus with numerous thin setae ventrally, arranged in more or less two rows; tibial spur moderate on legs III and IV; basitarsal spurs moderate to strong on legs I to IV; retrolateralbasitarsal spur withbasal tooth simple (notbifid). Trichobothriotaxy: trichobothrial pattern of TypeA, orthobothriotaxic as defined by Vachon (1974). Dorsal trichobothria of femur arranged in β (beta) configuration ( Vachon,1975).

Morphometric measurements (mm) of the male holotype.

– Total length: 87.26.

– Carapace

length 9.50;

anterior width 5.63;

posterior width 10.63.

– Mesosoma: length 23.0.

– Metasomal segments

I: length 6.75; width 6.75;

II: length 7.88; width 6.88;

III: length 8.50; width 7.13;

IV: length 10.13; width 6.88;

V: length 11.0; width 6.25; depth 5.25.

– Telson: length 10.5.

– Vesicle: width 3.94; depth 3.19.

– Pedipalp

femur length 7.63; width 2.88;

patella length 8.88; width 4.38;

chela length 16.63; width 4.13; depth 4.88;

movable finger length 10.63.

Relationships. – By its general morphology, size and coloration, Androctonus ajjer sp. n. shows similarities with A. amoreuxi , described from Egypt and distributed in Algeria in the core region of the Sahara, extending up to the Algerian Saharan massifs to the south ( Fig. 13).

The new species can however be readily distinguished by the following main features:

(i) metasomal segments I-IV with a moderately to strongly marked dorsal depression (reduced in A. amoreuxi );

(ii) dorsal carinae strongly marked with granules becoming spinoid posteriorly, segments III-IV with one bigger posterior spinoid granule (small rounded granules in A. amoreuxi and no pronounced posterior spinoid granules);

(iii) movable finger with 12 rows of granules (13-14 in A. amoreuxi );

(iv) distinct type of habitat ( A. amoreuxi is distributed in the deserts of the core Saharan region, generally under 1000 m a.s.l.). The Androctonus population of Djanet examined by Vachon (1955) most certainly corresponds to the new species described here (see Introduction).

Androctonus ajjer sp. n. can also be easily distinguished from the other Androctonus species distributed in the Saharan massifs, notably by the following main features:

- A. eburneus described from Djanet:

(i) much smaller overall size with 47.6 mm in adult male lectotype (87.26 in the new species);

(ii) lighter general coloration, without darker pigmentation on metasoma and telson;

(iii) higher pectinal tooth count with 38-37 teeth in male lectotype (31-33 in the new species);

(iv) movable finger with 13 rows of granules (12 in the new species).

- A. hoggarensis , described from the Hoggar Massif (Tassili n’Ahaggar) and also distributed in the Tassili n’Ajjer:

(i) general coloration dark brown to blackish (yellowish to brownish yellow in the new species);

(ii) fixed and movable fingers with 13 and 14-15 rows of granules, respectively (12 in the new species);

(iii) leg retrolateral basitarsal spurs with basal tooth bifid (simple in the new species);

(iv) distinct type of habitat ( A. hoggarensis is a mountain species that lives at high altitude, generally between 1200-2000 m a.s.l.).

- A. santi , described from the Aïr Massif:

(i) smaller overall size with 65-70 mm in adult males (87.26 in the new species);

(ii) general coloration dark brown to blackish (yellowish to brownish yellow in the new species);

(iii) distinct type of habitat ( A. santi is a mountain species that lives at high altitude (recorded between 1200-1600 m a.s.l.) in the Aïr Massif, separated from the Hoggar and Tassili n’Ajjer massifs by arid plains) ( Fig. 13).

Finally, Androctonus ajjer sp. n. can be distinguished from A. australis , distributed in Algeria between the high plateaus to the north, extending up to Ghardaïa and Ouargla to the south, notably by the following main features:

(i) metasomal segments strongly enlarged posteriorly (approximately the same width in the new species);

(ii) movable finger with 14 rows of granules (12 in the new species);

(iii) leg retrolateral basitarsal spurs with basal tooth bifid (simple in the new species);

(iv) anal arc with three lateral lobes (four in the new species);

(v) pectines with fulcra bearing one macroseta internally (one microseta in the new species).

Ecological characteristics of the type locality. – The region of Djanet is located on a geological fault at the far southeast of Algeria, forming a sandstone cliff that rises along the western edge of Oued Edjériou. These sandstones have preserved the traces of significant geological and climatic events that the region has experienced (orogeny, glaciation, volcanism, marine transgressions and regressions, sedimentation, fluvial and aeolian erosion) ( Dubief, 1999). The region is now dominated by dune fields or ergs that crown and envelop the Tassili n’Agger foothills, which are signs of increasingly growing aridity ( Beddiaf, 2020). The factor exacerbating this aridity is the rainfall, which is low (around 20mm /year) and irregular, with the months receiving the most rain being September (3.5 mm) and March (2.7 mm) ( Abdoun, 2002). The temperature is relatively stable, with an average temperature of over 31.1°C, a minimum temperature of 1.1°C recorded in January, and a maximum temperature of 32.6°C recorded in August ( Beddiaf, 2020). Eferi, the type locality of Androctonus ajjer sp. n., is an urban area surrounded by sandblasted cliffs, interspersed with date palm orchards and other crops, contributing to the improvement of the relative humidity in this desert region ( Fig. 11-12).