Protochactas furreri, Magnani & Stockar & Lourenço, 2022

Magnani, Fabio, Stockar, Rudolf & Lourenço, Wilson R., 2022, A new family, genus and species of fossil scorpion from the Meride Limestone (Middle Triassic) of Monte San Giorgio (Switzerland), Faunitaxys 10 (24), pp. 1-7 : 4

Protochactas furreri sp. n., Lourenço, Magnani & Stockar

( Fig. 3 - 14 )

ZooBank:http://zoobank.org/ CB86D102-AE88-4C4A-B8DC-1A0A491E4978

Type material. Holotype, MCSN 8613 . Possibly an adult or pre-adult, in part and counterpart. Only the dorsal aspect is observable. Sex cannot be defined.

Type locality. – Monte San Giorgio , Acqua del Ghiffo , NW of the Meride village , Mendrisio (Canton of Ticino, Switzerland) ( Fig. 1 ).

Type horizon. – Level 350 of the Cava superiore beds, lower Meride Limestone, early Ladinian ( P. gredleri ammonoid zone), Middle Triassic of Southern Alps ( Fig. 2 ).

Depositary. – Museo cantonale di storia naturale ( MCSN, Lugano, Switzerland)

Patronym. – The species is named after Dr. Heinz Furrer, former curator at the Paleontological institute and museum of the University of Zurich, who in 1997-2004 led the first systematic excavations in the Cava superiore beds at Acqua del Ghiffo.

Diagnosis for the new species. – The same as for the new family.

Description

Coloration. – Globally brown to reddish-brown, with some zones slightly darker; it is uncertain however if this colour pattern is original or an artefact due to the preservation.

Morphology. – Prosoma: anterior margin of carapace weakly convex; tegument rather smooth with some vestigial carinae and furrows. Median ocular tubercle conspicuous and slightly anterior to the centre of the carapace; median eyes separated by about one ocular diameter; two pairs of lateral eyes can be observed. Mesosomal tergites rather smooth with one vestigial median carina. Tergites VI and VII with some weak carinae. Sternites not observable. Pectines not observable. Metasomal segment with strongly marked dorsal and sub-dorsal carinae; ventral carinae probably absent with a ventral aspect smooth. Telson smooth; vesicle with a round shape, flattened dorso-ventrally; aculeus slightly curved and shorter than vesicle; subaculear tooth absent. Chelicerae bulk with only a few teeth observable ( Vachon, 1963). Pedipalps rather bulk, with chelahand globular and chela-fingers short; femur probably pentacarinate; patella and chela with vestigial. Trichobothrial pattern extremely incomplete but recalling a possible ‘basic’ type C ( Vachon, 1974). Chela manus with 2-3 trichobothria, Db, and 2 Eb. Patella with d 1, d 2, and i. Femur with d, i and e ( Fig. 7-8 ). Dentate margins of fixed finger probably composed of a single linear row of granules. Legs: Ventral aspect of tarsi and spurs not observable.

Morphometric values (mm) of the holotype of Protochactas furreri sp. n.

– Total length (including telson) 27.0.

– Carapace: length, 3.1; anterior width, 2.9; posterior width, 3.5.

– Mesosoma : length, 6.8.

– Metasomal segments

I: length, 1.8; width, 2.0;

II: length, 2.1; width, 1.9;

III: length, 2.2; width, 1.8;

IV: length, 2.4; width, 2.4;

V: length, 3.0; width, 2.4.

– Telson : length, 3.1; width, 1.1.

– Pedipalp (right /left)

femur length, 2.8/2.7, width, 1.1/1.0;

patella length, 2.5/2.5, width, 1.1/1.3;

chela length, 5.3/5.4, width, 2.4/2.0;

movable finger length, 3.3/3.5.

Figures

Fig. 3-8. Protochactas furreri sp. n., holotype.

Fig. 9 -14. Protochactas furreri sp. n., holotype. 9 -10. Habitus. 9 (part), 10 (counterpart). 11-12. Left and right pedipalps (counterpart). 13. Sternites VI and VII and metasomal segments I and II showing carinae (counterpart). 14. Telson in detail (counterpart).

Fig. 1. Map of the Monte San Giorgio area (Ticino, Southern Switzerland), showing the carbonate Anisian-Ladinian sequence together with the Acqua del Ghiffo locality (modified from Stockar, 2010).

Fig. 2. Stratigraphic column of the Monte San Giorgio area. The finding level of the new specimen is indicated. Stratigraphy after Commissione scientifica transnazionale Monte San Giorgio 2014, modified. U-Pb ages after Stockar et al. (2012).