Palaeobutheolus Lourenço, 2025

Genus Palaeobutheolus Lourenço gen. n.

ZooBank:https://zoobank.org/ FA76305B-CC65-4573-B818-824E1C50B764

Type species. – Palaeobutheolus andreschmidti Lourenço sp. n.

( Fig.3-1 5)

ZooBank:https://zoobank.org/ 60552926-E41F-4722-972F-A2B3BF4640AE

Diagnosis for the new genus. – The general morphology of the new scorpion is similar to that of some genera of extant buthoid scorpions (e. g. Butheolus and Hottentotta ), but also with that of one buthid genus previously found in Burmite, namely Cretaceousbuthus Lourenço, 2022 . In account however, of some marked distinct characters presented by the new species, a new genus is proposed to accommodate it. Specimen rather bulk with moderately long pedipalps. Anterior margin of carapace with a vestigial concavity, almost straight. Two large median eyes and three pairs of lateral eyes. Sternum pentagonal. Tergites with one median carinae and two weak lateral carinae. Metasomal segments approximately rounded and with possibly 10 carinae on I-II; 8 carinae on III-IV. Telson rounded in shape, without any sub-aculear tooth but with a pseudo annular ring, character rather uncommon among buthids. Chela fingers with 8-9 rows of small granules, separated by slightly bigger central accessory granules.Trichobothrial pattern similar to that of extant buthid type A (Vachon 1974); the dorsal trichobothria of femur presenting a beta disposition (Vachon, 1975). Femur majorante neobothriotaxic with 4 internal, 5 dorsal and 3 external. Patella minorante neobothriotaxic with 1 internal,dorsal d 1 to d 5 but absence of d 2; a number of external trichobothria can be observed at least by the presence of thin hairs; ventral trichobothria absent. Chela with at least 6 trichobothria on fixed finger, dt, db, et, est, esb and eb and6-8on chela hand, Et, Est, Esb, Eb 1 and Eb 3; Eb 2 may be absent. On ventral aspect, V 1 may also be absent. Cheliceral dentition similar to that defined for buthids by Vachon (1963); two small basal teeth on both fingers.Tibial spurs present on legs III and IV, moderate in size.Pedal spurs present in all legs.

Derivatio nominis. – Generic name associates Palaeo (ancient) with the extant genus Butheolus , and indicates its close association with this genus.

Diagnosis for the new species. – The same as for the new genus. Holotype. – Most certainly a pre-adult male.

Type locality and horizon. – Myanmar (Burma), Kachin; precise locality unknown; Lower Cretaceous .

Patronym. – The specific name honors Mr Andrè Schmidt, (Zofingen, Switzerland)., who supported the present study.

Depository. – The type specimen is deposited in the collections of Mr Andrè Schmidt , ( Zofingen, Switzerland) .

Description

Coloration. – The scorpion is yellow to slightly reddish-yellow with some darker zones on carapace and metasoma. Only the areas covered by a black substance or vegetal debris prevent a good observation.

3. Carapace, dorsal aspect. 4. Sternites II to VII showing spiracles 5. Ventral aspect showing coxapophysis, sternum and genital operculum. 6. Metasomal segment V and telson, latero-ventral aspect. 7. Leg IV, showing spurs. 8 - 11. Trichobothrial pattern. 8 - 9. Chela dorso-external and ventral aspects. 1 0 - 11. Patella and femur, dorsal aspect.

Morphology. – Carapace weakly granular, mostly in the lateral regions; anterior margin with a weak concavity, almost straigth. Carinae inconspicuous; furrows weak. Median ocular tubercle largely anterior to the centre of the carapace; median eyes conspicuous and separated by more than one ocular diameter; three pairs of marked lateral eyes. Sternum pentagonal. Genital operculum with two semioval flattened plates. Mesosomal tergites weakly granular to smooth, with one median carina and two inconspicuous lateral carinae; VII with five carinae; the lateral weak and the internal inconspicous. Pectines large, with 19-20 teeth; fulcra present but reduced. Sternites apparently smooth with small rounded spiracle. Metasomal segments I and II apparently with 10 carinae; III-IV with 8 carinae without spinoid granules; segment V with 5 carinae; all segments are rounded, in particular V. Telson rounded in shape with two strong ventral carinae; sub-aculear tooth absent but presence of a pseudo annular ring. Chelicera with buthid type dentition ( Vachon, 1963); fixed and movable fingers with two small basal teeth. Pedipalp femur pentacarinate; patella with 6-7 carinae; both segments weakly granular; internal face of femur and patella with spinoid granules; chela weakly elongated with vestigial carinae; chela fingers with 8-9 rows of small granules, separated by slightly bigger central accessory granules. Trichobothrial pattern similar to the extant buthid type A (Vachon 1974). See diagnosis for details. Legs tarsi with short spinoid setae forming more or less a brush. Tibial spurs present on legs III and IV, moderately marked; pedal spurs present on legs I-IV weak to moderate in size.

Morphometric values (mm). Male holotype of Palaeobutheolus andreschmidti Lourenço gen. n., sp. n.

– Total length including telson, 9.45.

– Carapace length 1.14;

anterior width 0.91;

posterior width 1.54.

– Mesosoma length 1.64.

– Metasomal segments

I: length 0.74, width 0.74;

II: length 0.91, width 0.74;

III: length 1.04, width 0.81;

IV: length 1.07, width 0.82;

V: length 1.64, width 0.83.

– Telson length 1.27;

width 0.54;

depth 0.44.

– Pedipalp femur length 1.09, width 0.35;

patella length 1.28, width 0.39;

chela length 2.07, width 0.34;

movable finger length 1.27.