Palaeoeuscorpiidae Lourenco 2003
Creators: name: Soleglad, Michael E.
name: Fet, Victor
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Scorpiones
Palaeoeuscorpiidae

description: Family Palaeoeuscorpiidae Lourenço, 2003 – Extinct.    Type Genus. Palaeoeuscorpius Lourenço, 2003. – Extinct.   
 Composition. The family is monotypic, with a single monotypic genus Palaeoeuscorpius.   
 Geological occurrence. Cretaceous of Europe (France) (amber).   
 Taxonomic history. The name given by Lourenço (2003) implies some relationship with modern Euscorpiidae, and the family was originally placed in the superfamily Chactoidea (sensu Lourenço, 2000).   
 Diagnosis. See Lourenço (2003) for details on the diagnosis of this family.   
 Discussion. This family indeed has features shared with parvorder Iurida, in particular the important neobothriotaxy on the ventral aspect of patella. However, we do not find any specific features which would allow including Palaeoeuscorpiidae unequivocally in Chactoidea, as did Lourenço (2003). The reported trichobothrial pattern could as well belong to a member of Scorpionoidea. In Lourenço’s (2003) Figs. 5–9, a partial trichobothrial pattern is shown for the dorsal-external and ventral aspects of the chela (12 trichobothria), and the dorsal and ventral aspects of the patella (29 trichobothria (11 accessory)); trichobothrial pattern of the femur is unknown. In this pattern, major neobothriotaxy is well illustrated on the patellar ventral surface, with 14 trichobothria in view. This is an important observation, since we now know that neobothriotaxy in this species occurred at least 100 Ma ago, derived from the orthobothriotaxy which is presumably Type C (we known from the five “palaeo-buthids” described by Lourenço & Weitschat, 1996, 2000, 2001, that Type A existed at least 65–55 Ma.). On the chela (from the left pedipalp) we see three ventral trichobothria, presumably  V 1 –V 3  and  Et 1  with the ventroexternal carina curving inward, toward the internal condyle. The apparent absence of trichobothrium  V 4  on the ventral surface is an indication of the euscorpiids, endorsing the conclusion made by Lourenço (i.e., it is located on the external surface). On the dorsal-external aspect we see eight trichobothria, six on the palm and two on the fixed finger. The two trichobothria located on the fixed finger probably belong to the db–dt series, and may include as well the most dorsal distal trichobothrium seen on the palm. The three more proximal trichobothria presumably are Db, Dt, and  Eb 3 , although, as drawn in the figure, the Db and Dt are dorsal of the well-defined digital carina. The other two trichobothria found on the palm exterior are probably in the  Et 1 –Et 5  and/or Est series. Unlike in the chela, there is considerable confusion as to the designations of trichobothria found on the patella, the text of Lourenço and the figures are not consistent. We can see a definite internal trichobothrium (i),  d 1 , and a second basal dorsal trichobothrium which more likely belongs to the external series. Fig. 7, which shows the dorsal aspect of the patella, and Fig. 8, which shows a somewhat skewed external view, angled internally, are, in part, composite figures. As it turns out (Lourenço, 2003, pers. comm.) only the dorsal and ventral views were visible on the fossil, the external view shown in Lourenço’s Fig. 8 is a composite of these two views. The external view shows six trichobothria on the ventral side of the externomedian carina and six on the dorsal side, a total of 12 trichobothria. However, if we add in the somewhat displaced basal “dorsal” trichobothrium mentioned above, we have 13 trichobothria, the number found in Type C patterns. Of course, the positions of these trichobothria do not comply with conventional Type C patterns. This would imply, if all these interpretations are correct (which is unlikely), that neobothriotaxy occurred only on the patella ventral surface. In summary, it is clear that this fossil scorpion is probably Type C even though many trichobothria are unaccounted for, including the entire femur, 18 in all (14 alone for the chela).
description: Published as part of Soleglad, Michael E. & Fet, Victor, 2003, High-level systematics and phylogeny of the extant scorpions (Scorpiones: Orthosterni), pp. 1-175 in Euscorpius 2003 (11) on page 117, DOI: 10.18590/euscorpius.2003.vol2003.iss11.1, http://zenodo.org/record/13237351