Trypanothacus buettikeri (Hendrixson, 2006), comb. n.

(Figs. 90–108)

Buthacus buettikeri Hendrixson, 2006: 47–52, figs. 4–5, plates 3–4 (in part); Lourenço & Qi, 2006: 161; El-Hennawy, 2009: 121, 126; Lourenço & Leguin, 2009: 104, 107, tab. 1; Desouky & Alshammari, 2011: 195–196, figs. 6–7 (?) (in part); Kovařík et al., 2013: 3; El-Hennawy, 2014: 45; Kovařík et al., 2016b: 2; Kovařík, 2018: 7.

TYPE LOCALITY AND TYPE DEPOSITORY. Saudi Arabia, Um ad- Dabah, NHMB.

TYPE MATERIAL EXAMINED. Saudi Arabia: 1♂ (holotype), Um ad-Dabah [23°54'N 45°01'E, 920 m a.s.l.], 13. V.1980, leg. W. Büttiker, NHMB 0587 (=172a); 1♀ (paratype), Khashm Dhibi [23°50'N 45°05'E, 750 m a.s.l.], 10.X.1981, leg. W. Büttiker, NHMB 0896 (=172e); 3♀ 1 juv. (paratypes), Kushm Dibi [24°14'N 46°05'E, 850 m a.s.l.], 30.I.1981, leg. W. Büttiker, NHMB 172cd.

OTHER MATERIAL EXAMINED. 1♂ (fragmented), Wadi Turabah [25°30'N 41°17'E, 1,430 m a.s.l.], XII.1986, leg. W. Büttiker, NHMB Sc509.

DISTRIBUTION. SAUDI ARABIA. Central plateau, Najd desert; east of Harrat Khaybar lava field, east of Hijaz mountains.

DIAGNOSIS. A member of Trypanothacus gen. n. differentiated from its congener as follows: pedipalp femur L/W ♂ 2.5, ♀ 2.2; pedipalp patella L/W ♂ 2.1–2.2, ♀ 2.3, chela L/W ♂ 3.2–3.6, ♀ 4.0; metasoma IV L/D ♂ 1.8–2.0, ♀ 1.9, V L/D ♂ 2.4–2.6, ♀ 2.4.

COMMENTS. Hendrixson originally described Buthacus buettikeri on the basis of a series of specimens from several localities in Saudi Arabia (Hendrixon, 2006: 47, 51). We examined part of the type series and concluded that the holotype male (No. 172a; Figs. 43, 90–91, 94–101) and paratype females from Khashm Dhibi (Nos. 172cd, NHMB 0896=172e; Figs. 44, 92–93, 103–106), from the Najd plateau region of central Saudi Arabia, belong to Trypanothacus gen. n .. However, several other specimens of the type series from widely disjunct sites along the western slopes of the Asir ranges (facing the Red Sea Coast), differed from the holotype and are associated with the Buthacus leptochelys (Ehrenberg, 1829) species complex of the genus Buthacus (i.e., female paratypes including NHMB 515=172b, 630=172f and 620= 172g; from Jabal al-Ghamdiyah, Wadi Maraum, Addar, Kijat (examined); also likely including MNHN RS8425 from Makkah By-pass, based on specimen photographs on the MNHN website). In light of these misidentifications, the status of other MNHN paratypes from a widely disjunct site near the northern border of Saudi Arabia (ca. 1,030 km from the type locality) remains unclear.

Desouky & Alshammari (2011) recorded B. buettikeri from the Ha’il region in the central plateau of Saudi Arabia (Hufair, Sarraa near Al-Ghazala), on “sandy desertˮ. In photographs, their adult female (carapace L 5.92 mm) (fig. 7) appears morphometrically consistent (e.g. patella L/W 2.57, metasoma I L/W 1.02) with females of the type series that we have examined, however their adult male (carapace L 6.4 mm) (fig. 6) has markedly different morphometrics with much more slender pedipalps and metasoma (e.g. pedipalp patella L/W 2.95, metasoma I L/W 1.38) than in the male types of B. buettikeri . It is also more slender than all males of T. barnesi sp. n. in our type series. This would seem to indicate large variation in male morphometrics of B. buettikeri, maybe reflecting local geographic races as Ha’il is located some distance northwest of the type locality. However, a large adult male that we determined as T. buettikeri, has morphometrics more robust than the holotype, yet was collected from Wadi Turabah, relatively closer to the Ha’il region. As we have not studied Ha’il region material, we withhold judgement on the taxonomic status of those populations, but the large morphometric difference likely indicates a different species. Desouky & Alshammari (2011: 196) assumed B. williamsi Lourenço & Leguin, 2009, to be a junior synonym of B. buettikeri, but did not justify this by comparative study of the types of either species. They also claimed that the telson and aculeus in B. buettikeri was “clearly more slender and elongated” than in B. leptochelys, misrepresenting Hendrixson (2006), when the opposite is true.

AFFINITIES. See comments under T. barnesi sp. n.