Squalogaleus undetermined
Creators: name: Kriwet, Jürgen
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Protospinacidae
Squalogaleus
Squalogaleus undetermined

description: Squalogaleus sp.   
Fig. 3K.  
 Material.—A single tooth, BGRX 12509, Kłęby 1/37: 244.8–245.7 m. Callovian.   
 Description.—The single tooth is very small, the labial face being mesio−distally elongated. The crown is much broader than deep. The labial face is completely smooth and projects out over the root forming a very strong, almost horizontally directed visor. The labial contour of the visor is slightly concave with a central protuberance. In lateral view, the labial face is rectilinear and oblique. There is a rather broad central cusp, which is heavily abraded. The transverse cutting edge is well developed and forming two pairs of very low, blunt and rounded pairs of lateral cusplets.   
The lingual face is much less developed but more convex than the labial face. It is strongly concave in its upper part in lateral view. The lingual face extends downwards to form a well developed but narrow uvula that tapers consistently towards the base edge that supported by the lingual root protuberance. The uvula is quite high in lateral aspect. The crown/ root junction is well marked by a constriction. The tooth crown also juts out over the root laterally.  
The root is high and somewhat displaced lingually. The vascularisation is of hemiaulacorhize type. The root lobes are arched and V−shaped in basal view. A well−developed labial root depression is present. A large central foramen opens into the labial depression. The lingual root protuberance is damaged so that the morphology of the medio−lingual foramen is not visible. Two margino−lateral foramina are present on one side of the root. Smaller foramina open onto the labial area of the root depression.  
 Remarks.—The main characters of Squalogaleus teeth are: a very strong and labially elongated visor, a moderately developed uvula with pointed lingual extremity, a rectilinear to convex upper labial crown face and a concave lingual face in lateral view. The root is comparably high with rather large foramina compared to teeth of Protospinax. The main difference to teeth of Protospinax is the convex labial edge, which forms almost a labial protuberance. Conversely, the labial edge is concave in Protospinax. The overall morphology of the single tooth from Kłęby matches these characters and is therefore assigned to Squalogaleus. So far, skeletal remains are only known from a single species from the Tithonian (S. woodwardi Maisey, 1976). Teeth of Squalogaleus also occur in the Kimmeridgian of Spain (Kriwet 1998) and Toarcian of the Paris Basin (Laurent Candoni personal communication 1999). The record from the Callovian of Poland closes the gap between the known Early and Late Jurassic records. The tooth figured by Delsate and Lepage (1990) as Protospinax ? or Squalogaleus ? from the Toarcian of Belgium might represent another taxon. The teeth described as Protospinax lochensteinensis by Thies (1983) are transferred to Squalogaleus (Candoni 1995) and its presence indicated in the Kimmeridgian of France.
description: Published as part of Kriwet, Jürgen, 2003, Neoselachian remains (Chondrichthyes, Elasmobranchii) from the Middle Jurassic of SW Germany and NW Poland, pp. 583-594 in Acta Palaeontologica Polonica 48 (4) on page 592, DOI: 10.5281/zenodo.13392170