Apatorhamphus is an extinct genus of azhdarchoid pterosaur from the Kem Kem Group of Morocco. It might have been part of the Chaoyangopteridae.[1] It is only known from a few snout fragments and it likely had a wingspan of between 3–7 metres (9.8–23.0 ft)
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.[1]
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.[1]
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.[1]
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, pteranodontids and the azhdarchid Bakonydraco. However the material of Apatorhamphus differs from these pterosaurs in a serious of morphological features.[1]
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.[1]