| Pholidosaurus | |
|---|---|
 | |
| Pholidosaurus meyeri skull fossil at the Museum für Naturkunde, Berlin | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archosauria |
| Clade: | Pseudosuchia |
| Clade: | Crocodylomorpha |
| Family: | †Pholidosauridae |
| Genus: | †Pholidosaurus Meyer,1841 |
| Species | |
| Synonyms | |
| |
Pholidosaurus is an extinctgenus ofneosuchiancrocodylomorph. It is thetype genus of thefamilyPholidosauridae. Fossils have been found in northwesternGermany. The genus is known to have existed during theBerriasian-Albian stages of theEarly Cretaceous. Fossil material found from theAnnero andJydegård Formations inSkåne,Sweden and on the island ofBornholm,Denmark, have been referred to as a mesoeucrocodylian, and possibly represent the genusPholidosaurus.[1]
An early description of the genus by Lydekker (1888) mentioned that theorbit is slightly smaller than the supratemporal fossa, thenasals reach thepremaxillae, and thevomer appears on thepalate.[2] It is similar in appearance to and about as large as the moderngharial.
Thetype species ofPholidosaurus isP. schaumburgensis, named in 1841 from theWealden ofBückeburg, Germany.[2][3]P. schaumburgensis was named on the basis of a natural mold of part of a thorax discovered in around 1830 from the BerriasianObernkirchen Sandstein.[4] This mould is known as IMGPGö 741-1. The individual that the mould belonged to is thought to have been around 25 centimetres (9.8 in) in length.[5]
Macrorhynchus is ajunior synonym ofPholidosaurus.[6] It was named in 1843 from the same stratigraphic unit and region asP. schaumbergensis, with the type species beingM. meyeri.[7] BecauseM. meyeri bears a strong resemblance toPholidosaurus schaumburgensis, it is now regarded as a species ofPholidosaurus. It was reassigned to the genusPholidosaurus in 1887 byRichard Lydekker because of this synonymy, and also because the nameMacrorhynchus was preoccupied by a genus of fish named in 1880.[3]P. meyeri differs fromP. schaumburgensis in that the bar separating the supratemporal fenestrae is rounded, while in the type species it is rounded.[2]
Pholidosaurus decipiens was erected for a partial cranium, NHMUK 28432, that was originally assigned to the new genus and speciesPetrosuchus laevidens byRichard Owen in 1878.[8]Petrosuchus laevidens was based on this cranium and a mandibular ramus called BMNH 41099, both of which were collected fromSwanage, England. A later study in 1911 concluded that the material belonged to two different species; NHMUK 28432 was reassigned toPholidosaurus and NHMUK 41099 was designated the lectotype ofPetrosuchus laevidens. The species namedecipiens was coined in reference to Owen's oversight, andPetrosuchus is now considered a junior synonym ofGoniopholis simus.[5]
Another species from England,P. purbeckensis, was originally described as a species ofSteneosaurus in 1888.[9] The holotype is an almost complete cranium, referred to as DORCM G97, missing the anterior portion of the rostrum. The skull was found from either Swanage or theIsle of Purbeck (hence the species name), although the exact locality from which the skull originated is not specified by the author of the original description.[10] This material was also once referred toMacrorhynchus. The author of the 1888 description consideredS. purbeckensis an intermediate form betweenSteneosaurus andTeleosaurus.[9] However, in 2002, a new study showed thatS. purbeckensis was conspecific withP. decipiens, creating the new combinationPholidosaurus purbeckensis.[5]
Another species ofPholidosaurus,P. laevis, was named in 1913 from Swanage, based on the partial cranium NHMUK R3414.[11] This has been considered a junior synonym ofP. purbeckensis by both Salisburyet al. (1999) and Salisbury (2002).[5][12]
In an SVPCA abstract, Smithet al. (2016) noted thatPholidosaurus purbeckensis is not congeneric with the type species, and instead is closely related toFortignathus and members ofDyrosauridae.[13]
| Phylogenetic position ofPholidosaurus | ||
| ||
|
Richard Lydekker assignedPholidosaurus to the familyGoniopholididae in 1887 along withHylaeochampsa,Theriosuchus,Goniopholis, andPetrosuchus because thevertebrae areamphicoelus and the orbit communicates with the lateraltemporal fossa.[3]
Pholidosaurus has often been grouped with other longirostrine, or long-snouted, crocodylomorphs, includingdyrosaurids andthalattosuchians. Buckley and Brochu (1999) concluded thatPholidosaurus,Sokotosuchus, Dyrosauridae, and Thalattosuchia formed a longirostrineclade that was thesister taxon toCrocodylia.[16] However, Thalattosuchia was traditionally considered a more basal clade of crocodylomorphs, being a more basal lineage ofMesoeucrocodylia than dyrosaurids orPholidosaurus, both of which were considered neosuchians.[17] The results of the phylogenetic analysis by Buckley and Brochu (1999) were attributed to the similarity in characters associated with snout elongation seen in these crocodylomorphs, even though these characters may have beenindependently derived in each group. More recent studies have revealed Thalattosuchia as a more basal clade when dyrosaurids are removed from the data set.[18]
More recent studies show thatPholidosaurus is closely related to the Thalattosuchia, with both taxa closely related to a clade containingTerminonaris and the Dyrosauridae.[19] In a phylogenetic analysis conducted by Serenoet al. (2001),Pholidosaurus was placed as a distant sister taxon to the other longirostrine crocodylomorphs, withTerminonaris and the newly namedSarcosuchus being closely related to one another andDyrosaurus being the next closest taxon to the group.[14] The later phylogenetic analysis of Brochuet al. (2002) again showed thatPholidosaurus was closely related to Thalattosuchia. In the study, both taxa formed a clade that was the sister taxon to a clade containingSokotosuchus and Dyrosauridae.[20] Jouveet al. (2006) concluded thatPholidosaurus was closely related thalattosuchians were also included within the family, which would be consideredparaphyletic without them. Jouveet al. (2006), like Buckley and Brochu (1999), attributed this result to phylogenetic problems that exist among longirostrine crocodylomorphs due to similarities in their morphology.[21]
{{cite book}}: CS1 maint: location missing publisher (link){{cite web}}: CS1 maint: archived copy as title (link)
| |||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||
