Chaerilobuthus petersi Lourenço, 2024

Chaerilobuthus petersi Lourenço sp. n.

( Fig. 1-8)

ZooBank:https://zoobank.org/ 77C18365-437A-4B06-8CB9-971C1777E09A

Holotype. – Most certainly a male juvenile. Type locality and horizon: Myanmar (Burma), Kachin; precise locality unknown; Lower Cretaceous.

Patronym. – The specific name honours Mr Dieter Peters (Gelsenkirchen, Germany), who supported the present study.

Depository. – The type specimen is deposited in the collections of Mr Dieter Peters ( Gelsenkirchen, Germany) .

Diagnosis. – As for most previously described species of Chaerilobuthus , the general morphology of the new species follows the standards defined for the family Chaerilobuthidae . Carapace only weakly emarginated anteriorly; both median and lateral eyes absent; the almost total absence of eyes was only previously observed for Chaerilobuthus birmanicus Lourenço, 2015 . A possible presence of a macula in the place of lateral eyes; characters previously observed only for Chaerilobuthus meggeri Lourenço, 2021 . Pedipalps globally elongated; relationship between chela length vs chela width equal to 6.35 ( Lourenço & Velten, 2022); spinoid granules absent from the internal aspect of patella. Pectines are very roughly observed, but appear as rather large with 10-11 teeth, a record among the species of the genus; fulcra absent; sternum approximately pentagonal and conspicuous, slightly longer than wide; genital operculum with two rounded plates; spiracles very small and slightly rounded to semi-oval in shape; cheliceral dentition partially observed; movable finger with two distal teeth; distal teeth of fixed and movable fingers very long and overlapping for about one half of their length; fixed and movable fingers with one basal and one median tooth; vesicle moderately bulbous with a thin and long aculeus. Trichobothrial pattern related to those of buthoids and chaeriloids, recalling types A and B, as defined by Vachon (1974) with at least 2 dorsal and 4 external trichobothria on the femur; 2-3 dorsal, 1 internal and 4-5 external on the patella; 2 dorsal and 3-4 external on chela hand and 5-6 on fixed finger.

Description

Coloration. – The scorpion is reddish-yellow to brownish-yellow with some dark reddish zones; carapace, tergites and sternites brownish-yellow; metasomal segments brownish-yellow; telson reddish-brown; pedipalps and legs reddish-yellow. Ventral aspect reddish-yellow; pectines yellow.

Morphology. – Carapace without granulations; almost smooth; anterior margin with a weak median concavity. Carinae and furrows weak or absent. Median ocular tubercle totally absent; median and lateral eyes equally absent; possible presence of a macula in the place of lateral eyes. Sternum approximately pentagonal and conspicuous, slightly longer than wide. Mesosomal tergites not granular as carapace and with weakly marked carinae; VII with five weakly marked carinae. Pectines are roughly observed, but are large and with 10-11 teeth; fulcra absent; the zone with peg sensillae can be observed on some teeth. Sternites can be roughly observed since they suffered with the dissection process; almost smooth, with small spiracles small and slightly rounded to semi-oval in shape. Metasomal segments I to IV with 10-8-8-8 observable carinae; dorsal without spinoid granules; segment V with five carinae; ventral carinae on segments I-IV weakly marked; setation on segments I to V moderate. Telson with a moderately bulbous vesicle; weakly granular to smooth and a strong setation; aculeus long but moderately curved. Cheliceral dentition partially observed; movable finger with two distal teeth; distal teeth of fixed and movable fingers very long and overlapping for about one half of their length; fixed and movable fingers with one basal and one median tooth (Vachon, 1963). Pedipalps globally elongated; femur pentacarinate with inconspicuous spinoid granules on internal face; patella with dorso-internal, ventro-internal, dorso-external, external and ventral carinae; spinoid granules on internal face inconspicuous or absent. Chela with moderately to weakly marked carinae; all faces weakly granular to smooth; internal face without spinoid granules. Fixed and movable fingers with 6-7 longitudinal rows of small, rounded granules, separated by slightly bigger accessory granules; extremity of fingers with one stronger spinoid granule. Trichobothriotaxy: a trichobothrial pattern related to those of both buthoid and chaeriloids, types A and B can be observed (Vachon, 1974); for details see diagnosis. Leg tarsi with thin ventral setae. Pedal spurs present and weakly marked; tibial spurs absent.

Morphometric values (mm), holotype of Chaerilobuthus petersi Lourenço sp. n.

– Total length (including telson) 4.97.

– Carapace length 0.81,

anterior width 0.42,

posterior width 0.54.

– Mesosoma length 1.57.

– Metasomal segments

I: length 0.21, depth 0.21;

II: length 0.23, depth 0.21;

III: length 0.27, depth 0.19;

IV: length 0.37, depth 0.18;

V: length 0.74, depth 0.17.

– Telson length 0.77.

– Vesicle depth 0.17.

– Pedipalp femur length 0.57, width 0.32;

patella length 0.75, width 0.24;

chela length 1.08, width 0.17;

movable finger length 0.67.

Relationships. – In account of the total absence of eyes, the new species seems to be related to Chaerilobuthus birmanicus Lourenço, 2015 , species with only extremely reduced lateral eyes ( Lourenço, 2015). The presence of a possible macula in the place of lateral eyes, associates the new species to C. meggeri Lourenço, 2021 . The new species can however, be distinguished from these two species by a combination of characters: (i) total absence of eyes and/or possible presence of a macula, (ii) anterior margin of carapace weakly emarginated; straight in C. birmanicus , (iii) pedipalps globally elongated, in particular chelae; relationship between chela length vs chela width equal to 6.35 while in C. birmanicus and C. meggeri these values range from 3 to 4 ( Lourenço & Velten (2022).