Cretaceoushormiops staxi Lourenço, 2022

Cretaceoushormiops staxi Lourenço sp. n.

(Fig. 1 -6, 9 -13, 14- 18)

ZooBank:http://zoobank.org/ A03C30A5-47EC-4C48-948A-87B13BA404A9

Type material. – Holotype, a possible juvenile or pre-adult.According to the morphology of pectines and genital operculum, with a single plate, it can be defined as a female.

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

Name. – Honors Dr Dietmar Stax (Pfungen, Switzerland) who arranged facilities for the study of the specimen.

Depositary. – The type specimen is deposited in the Collection of Dr Dietmar Stax (Pfungen, Switzerland) .

Diagnosis for the new species

Total length 11.30 mm (to notice that the mesosoma is strongly contracted). General coloration yellow to bright yellow. Carapace with a moderately to weakly marked median concavity; median ocular tubercle anterior to the centre of the carapace and with large median eyes; two lateral eyes can be observed; a possible third pair of vestigial eyes may exist. Sternum pentagonal in shape; slightly larger than long. Pectines moderate to large in size with 16-17 teeth; fulcra inconspicuous. Spiracles slightly oval. Metasomal segment I to V rounded and weakly flattened laterally with only dorsal and latero-dorsal carinae.Telson with a long pear-shaped vesicle weakly flattened laterally; no annular ring on the telson is observed. Fixed and movable fingers with one row of small rounded granules, without clear accessory granules; presence of 3-4 spinoid granules on the distal third of fingers; each finger terminating by a moderately to weakly marked spinoid process. Chelicerae only partially observed but showing a dentition similar to that defined for the Scorpionidae sensu Vachon (1963) . Tibial spurs absent; tarsi with two rows of spines. Trichobothrial pattern similar to type C defined by Vachon (1974) and also illustrated by Lourenço & Monod (1999) for the genus Hormiops . On the chela hand, trichobothria Db, Dt, Est, Et 1-5, Esb, Eb 1 to Eb 3 and four V can be observed. On the chela fixed finger, trichobothria eb, db, dsb, esb, dst, dt, est, et, ib and it can be observed.Patella shows d 1 and d 2 on dorsal face; i oninternal face; on the ventral face 3 V trichobothria are clearly observed and a diminutive V 4 is suspected. Accessory ventral trichobothria have being previously observed for extant Hormuridae species; e. g. Liocheles penta Francke & Lourenço, 1991 (Francke & Lourenço, 1991). 7-8 external trichobothria can be directly observed on the patella, but the presence of several transverse hairs suggests a higher number reaching a total of 12-13, which belong to territories et, est, esb, em, esb and eb. Femur shows one d, one i and one e.

Description

Coloration. – The scorpion is yellow to pale bright-yellow; carapace and tergites yellow; metasomal segments I to V yellow; telson slightly reddish-yellow; pedipalps and legs yellow to reddish-yellow. The ventral aspect of the specimen is yellow to pale yellow.

Morphology. – Carapace without granulations, almost smooth; anterior margin with a moderately to weakly marked median concavity. Carinae absent; furrows weakly marked. Median ocular tubercle anterior to the centre of carapace; median eyes moderate to large in size and separated by about one ocular diameter. Two pairs of lateral eyes; a possible third pair of vestigial eyes may exist. Sternum pentagonal, slightly larger than long. Mesosomal tergites without granulations, smooth, with one median vestigial carina; VII with five inconspicuous carinae. Pectines moderate to large in size with 16-17 teeth; fulcra inconspicuous. Sternites smooth with small slightly oval spiracles. Metasomal segment I to V rounded and weakly flattened laterally with only dorsal and latero-dorsal carinae; dorsal carinae of segments I to IV without any spinoid granules; dorsal aspect of segments I to V weakly depressed; setation on all segments strongly marked. Telson with a long pear-shaped vesicle weakly flattened laterally; not granular, smooth; aculeus short and moderately curved; absence of any annular ring on the telson;setation conspicuous. Cheliceral dentition only partially visible, similar to that defined for the Scorpionidae sensu Vachon (1963) . Pedipalp femur pentacarinate with some internal spinoid granules; patella with dorso-internal, ventro-internal, and dorso-external carinae; internal face with some minute spinoid granules and one moderate apophysis. Chela with moderately marked carinae; all faces smooth. Fixed and movable fingers each with one row of small rounded granules; no accessory granules are observable but 3-4 spinoid granules on the distal third of fingers can be observed; each finger terminating by a weakly marked spinoid process; setation of pedipalps weak to moderate. Tibial spurs absent; tarsi with two rows of small spines. Trichobothriotaxy similar to type C ( Vachon, 1974) of extant Hormuridae scorpions ( Lourenço & Monod, 1999). For details refer to the diagnosis.

Relationships

Most characters observed for this new species allow its inclusion in the genus Cretaceoushorpiops . Nevertheless, a few characters such as the presence of spines on the tarsi, instead of setae or the possible presence of a fourth ventral trichobothrium in the patella, could suggest a generic difference. The possibility of a new genus is however, rejected at present, mainly because these variations have also been observed in extant species, and mostly because some require yet further and more clear observations.

The new species of Cretaceoushormiops can however be distinguished from C. knodeli by a number of features:

(i) both species have similar global sizes, but the morphometric values are distinct; pedipalp fingers, in particular, are more bulk in the new species and the spinoid process in their tip is much less marked,

(ii) the anterior median concavity on carapace is less marked in the new species,

(iii) median eyes are bigger in the new species,

(iv) in Cretaceoushormiops staxi Lourenço , sp. n. the sternum is larger than long,

(v) in the new species pectines are larger and have a bigger number of teeth

16-17 vs 13-14 for C. knodeli ,

(vi) spiracles slightly oval in Cretaceoushormiops staxi Lourenço , sp. n.,

(vii) the possible presence of a fourth ventral trichobothrium on patella. Fig. 1 - 6. Cretaceoushormiops staxi Lourenço sp. n.

1. Carapace and chelicera. 2. Tarsi of leg IV, showing spines. 3. Metasomal segment V and telson, lateral aspect. 4. Sternum and genital operculum. 5. Sternites V to VII, showing spiracles. 6. Chela movable finger.

Fig. 7. C. knodeli . Chela movable finger.

Fig. 8. Betaburmesebuthus joergi . Male femur, dorsal aspect (scales, 1, 3, 4, 5 = 1 mm; 2, 6, 7, 8 = 0.5 mm).

Fig. 9 - 13. Cretaceoushormiops staxi Lourenço sp. n. Trichobothrial pattern.

9. Femur, dorsal aspect. 10-11. Chela dorso-external and ventral aspects. 12-13. Patella, dorsal and ventral aspects (scale = 1 mm).

Comparative morphometric values (mm) between the holotypes of Cretaceoushormiops knodeli Lourenço and Cretaceoushormiops staxi Lourenço sp. n.

– Total length (including telson) 12.83/11.30.

– Carapace length 1.80/1.87,

anterior width 0.94/1.20,

posterior width 1.60/1.74.

– Mesosoma length 5.07/3.65.

– Metasomal segments

I: length 0.67/0.74, width 0.34/0.47;

II: length 0.74/0.74, width 0.34/0.47;

III: length 0.80/0.81, depth/width 0.34/0.47;

IV: length 0.94/0.87, depth/width 0.34/0.47;

V: length 1.27/1.14, depth/width 0.47/0.41.

– Telsonlength 1.54/1.48.

– Vesicle: depth/width 0.44/0.41/0.34.

– Pedipalp femur length 1.54/1.61, width 0.54/0.54;

patella length 1.60/1.68, width 0.60/0.68;

chela length 3.14/3.30, width 0.54/0.76, depth?

movable finger length 1.87/1.78.

Second species also examined during this study