''Apatorhamphus'' is an extinct genus of azhdarchoid pterosaur from the Kem Kem Group of Morocco. It might have been part of the Chaoyangopteridae. It is only known from a few snout fragments and it likely had a wingspan of between

Discovery and naming

During a visit in 2016 to the Tafilalt phosphate mine on the Aferdou N'Chaft plateau, near Hassi el Begaa, in Er Rachidia, British paleontologist David Michael Martill purchased the jaw fragment of a pterosaur from miners (specimen ''FSAC-KK 5010''). They had dug a tunnel in a thin fossil-containing layer on the edge of a quarry and finds were offered for sale there. These fossils belong to strata that belong to the Kem Kem Beds and date to the Cretaceous period, between the Albian to

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

. In 2020, the new genus and species ''Apatorhamphus gyrostega'' was named and described by James McPhee, Nizar Ibrahim, Alex Kao, David M. Unwin, Roy Smith, and David M. Martill. McPhee ''et al.'' also referred various earlier finds to this new species. This concerns the specimens FSAC-KK 5011, FSAC-KK 5012 and FSAC-KK 5013, found at Begaa in Morocco; the FSAC-KK 5014 specimen, also in a Moroccan collection but of unknown origin; BSP 1993 IX 338, a snout found in 1993, reported as a possible pteranodontian in 1999 and assigned to '' Alanqa'' in 2010; and CMN 50859, a lower jaw identified in 2011 as a possible member of the

Dsungaripteroidea Dsungaripteroidea is a group of pterosaurs within the suborder Pterodactyloidea. Evolutionary history The earliest known fossils attributed to this group are from the Kimmeridgian-age Upper Jurassic Argiles d'Octeville Formation of France, dat ...

. The genus name is derived from Ancient Greek ''apatos'', "deceptive", and ''ramphos'', "snout", a reference to the difficulties one had in determining the taxonomic nature of the jaws and indeed whether it was an upper jaw or lower jaw. The species designation is a combination of the Greek ''gyros'', "rounded", and ''stegè'', "roof", a reference to the round cross section of the top of the muzzle.

Description

The holotype of ''Apatorhamphus'' consists of a fragmentary rostrum missing the tip of the beak and being broken off just anteriorly to the nasoantorbital fenestra. The anterior break is sharp and clean, suggesting that the tip was lost during collection, while the posterior break is withered and was most likely caused prior to burial. Due to the fragmentary nature of the material, preserving no key features such as the nasoantorbital fenestra, it is difficult to determine if the holotype represents a mandible or a fragment of the upper jaw. However McPhee ''et al.'' concluded that the fossil was most likely part of the upper jaw based on the relatively high lateral angle of the rostrum, which in most pterosaur taxa is greater than that of the mandible. Exceptions to this are

tapejarids Tapejaridae (from a Tupi word meaning "the old being") are a family of pterodactyloid pterosaurs from the Cretaceous period. Members are currently known from Brazil, England, Hungary, Morocco, Spain, the United States, and China. The mo ...

pteranodontids The Pteranodontidae are a family of large pterosaurs of the Cretaceous Period of North America and Africa. The family was named in 1876 by Othniel Charles Marsh. Pteranodontids had a distinctive, elongated crest jutting from the rear of the head ( ...

and the azhdarchid ''

Bakonydraco ''Bakonydraco'' is a genus of pterodactyloid pterosaur from the Late Cretaceous period (Santonian stage) of what is now the Csehbánya Formation of the Bakony Mountains, Iharkút, Veszprém, western Hungary. Etymology ''Bakonydraco'' was name ...

''. However the material of ''Apatorhamphus'' differs from these pterosaurs in a serious of morphological features. The rostral fragment is a total of 211mm long not including the missing tip. It is edentulous (toothless) with a slightly concave dorsal surface and a straight ventral margin. The lateral surface preserves a single row of foramina on each side, which appear to form alternating pairs between the left and right side, but this offset may be broken with the more posteriorly located foramina. The foramina are large and elongated and decrease in size anteroposteriorly. In cross-section the beak is oval towards the tip of the snout with some tapering towards the dorsal surface and a large ventral depression. As the beak moves further towards the end of the skull, the cross-section takes on a more "tear-drop" shape with noticeably convex lateral margins and a deeper occlusal groove. The walls of the bone are relatively thick throughout the specimen. Referred specimen FSAC-KK 5013 has a much lower rostral angle of only 6° (as opposed to the 14° of the holotype) with a straighter dorsal margin. As the fossil otherwise resembles the holotype in cross-section, occlusal pit and sharing the same single row of foramina, it has been interpreted to represent a mandibular fragment. This conclusion is supported by the fact that the occlusal surface of this specimen is almost perfectly complimentary to the holotype specimen.

Classification

An exact classification of ''Apatorhamphus'' is difficult due to its fragmentary nature, however a more approximate placement within Pterosauria is still possible. Due to the toothless nature of the rostral elements, it can only belong to either Azhdarchoidea or Pteranodontia. The fossils differ from those of Pteranodontians through the thicker bony walls, less pointed beak, shallower rostrum and the presence of the foramina along the lateral surface.

Dsungaripterids Dsungaripteridae is a group of pterosaurs within the suborder Pterodactyloidea. They were robust pterosaurs with good terrestrial abilities and flight honed for inland settings. Classification In 1964 Young created a family to place the recentl ...

are at least partially toothless, however the edentulous area of the beak is limited to the anterior end and relatively small. One possible exception would be '' Banguela'', however the placement of this taxon within Dsungaripteridae has been questioned and it furthermore greatly differs from ''Apatorhamphus'' due to its blade-like occlusal surface. ''Apatorhamphus'' can also be excluded from the Tapejaridae and Thalassodromidae as it lacks apomorphies with these groups. ''Apatorhamphus'' more closely resembles azhdarchids and chaoyangopterids. The lateral profile of ''Apatorhamphus'' is similar to those of multiple genera of chaoyangopterids. They also share the straight occlusal margin and gentle curve of the dorsal margin. Based on its similarities to ''

Chaoyangopterus ''Chaoyangopterus'' is a genus of chaoyangopterid pterosaur known from a partial skeleton found in Liaoning, China. ''Chaoyangopterus'' was found in rocks dating back to the Aptian-age Lower Cretaceous Jiufotang Formation of Dapingfang, Chaoy ...

'' and ''

Jidapterus ''Jidapterus'' is a genus of chaoyangopterid pterosaur from the Aptian-age Lower Cretaceous Jiufotang Formation of Chaoyang, Liaoning, China. The genus was in 2003 named by Dong Zhiming, Sun Yue-Wu and Wu Shao-Yuan. The type species is ''Jida ...

'' McPhee ''et al.'' tentatively assigned ''Apatorhamphus'' to Chaoyangopteridae.

Paleoecology

''Apatorhamphus'' was part of a diverse assemblage of pterosaurs native to Cretaceous North Africa, which inhabited an area offering a variety of ecological niches including ponds, lakes, marshes and river banks. During the Cretaceous this area was home to the azhdarchid '' Alanqa'', the tapejarid '' Afrotapejara'', a variety of

anhanguerids Anhangueridae is a group of pterosaurs within the suborder Pterodactyloidea. They were among the last pterosaurs to possess teeth. A recent study discussing the group considered the Anhangueridae to be typified by a premaxillary crest and a later ...

as well as ''

Xericeps ''Xericeps'' is a genus of pterosaur from the Late Cretaceous Kem Kem Beds (which date to the late Albian or Cenomanian age) of southeastern Morocco. The name ''Xericeps'' comes from the grc, ξερός - meaning dry, referencing the Sahara Des ...

'', another possible chaoyangopterid,Pêgas, R.V.; Holgado, B.; Ortiz David, L.D.; Baiano, M.A.; Costa, F.R. (August 21, 2021). "On the pterosaur Aerotitan sudamericanus (Neuquén Basin, Upper Cretaceous of Argentina), with comments on azhdarchoid phylogeny and jaw anatomy". Cretaceous Research. in press: Article 104998. doi:10.1016/j.cretres.2021.104998 and ''

Leptostomia ''Leptostomia'' is a genus of long-beaked pterosaur from the mid-Cretaceous (?Albian-Cenomanian) of Morocco, North Africa. The type species is ''L. begaaensis'', which was named and described in 2021 from sediments of the Kem Kem Group in Morocc ...

'', a long beaked azhdarchoid. However it is unclear which exact niche ''Apatorhamphus'' would have inhabited within this ecosystem.

References

{{Portal bar, Paleontology, Cretaceous, Morocco Chaoyangopterids Fossil taxa described in 2020