Nicorhynchus: a disputed name for toothed pterosaurs

Nicorhynchus is a proposed genus of large, toothed pterosaurs based chiefly on the front of the upper jaws of two species: the English N. capito and Moroccan N. fluviferox. The 2020 revision separated them from the historically overextended genus Coloborhynchus, emphasizing the shape of the rostral tip, tooth sockets and crest base. A 2023 review of the Kem Kem pterosaurs argued that these differences do not justify keeping Nicorhynchus separate, treating it as a subjective junior synonym of Coloborhynchus. The jaw anatomy is observable; the rank of the name remains disputed. The pterosaur catalogue records it with that taxonomic caveat.

Quick facts

Why the name was proposed

The species now called Nicorhynchus capito began as Ornithocheirus capito, named by Harry Seeley in 1870 from material in the Cambridge Greensand. Its name and referrals shifted as nineteenth- and twentieth-century workers tried to sort many isolated pterosaur jaws from southern England. In 2020, Borja Holgado and Rodrigo Pêgas re-examined the coloborhynchine complex and restricted Coloborhynchus more narrowly. They established Nicorhynchus for capito and transferred the Moroccan species fluviferox to it.

The type species N. capito is anchored by CAMSM B54625, an anterior upper-jaw fragment. Other English pieces have been referred by comparison, but their condition and history vary. The Moroccan N. fluviferox was named in 2019 from FSAC-KK 10701, which preserves the front of the rostrum and the first three pairs of tooth alveoli. Additional fragments were compared with it. Neither species is known from a complete skeleton.

Features visible in the rostrum

In N. capito, the end of the upper jaw expands into a broad, roughly squared area. The profile and depressions around the first tooth positions, together with the base of a sagittal crest, were among the features used in the 2020 diagnosis. The Moroccan rostrum has a different outline to the expanded region beneath the crest, described as a taller triangular shape. Its first sockets and shallow depressions also differ in arrangement. These distinctions are real observations in the fragments; whether they separate genera or species is a separate systematic interpretation.

The fragments do not show the back of the skull, the entire crest, the palate, most of the dentition or the postcranial skeleton. Some referred material has been used to infer variation in crest development. A small sample cannot tell whether a difference reflects growth, individual variation, sexual dimorphism or distinct taxa. Accordingly, no single cause should be presented as established.

A live question in classification

The 2020 paper placed Nicorhynchus among anhanguerid pterosaurs and proposed relationships within Coloborhynchinae based on a character analysis of the rostrum and other available features. The limited fossils make any tree sensitive to how incomplete taxa are coded and which referred specimens are accepted.

A 2023 review of the Kem Kem pterosaurs concluded that the fragmentary and worn morphology used to separate the genus was not taxonomically decisive and treated Nicorhynchus as a subjective junior synonym of Coloborhynchus. This means the authors judged the names to refer to the same genus, not that the name-bearing fossils were physically identical. The 2020 combination remains widely encountered in databases and discussion, while the synonymy is a published competing view. An evidence-led account should state both rather than silently presenting one as universally accepted.

Size, feeding and reconstruction

The broad jaws and enlarged front teeth fit a grasping function, and fish or other aquatic animals are plausible prey in the coastal settings represented by the deposits. No specimen preserves a meal, bite mark or other direct record of what the animal ate. A fish-eating lifestyle is therefore a functional and ecological inference, not something visible in a tooth socket.

Because the known pieces are from the front of the jaws, a reliable wingspan cannot be calculated from the type material. Estimates require referrals or proportions borrowed from related pterosaurs. A full image adds the rear skull, crest outline, neck, trunk, wings, membrane, skin and colour. The secure comparison is narrower: English and Moroccan rostral fragments with distinctive but disputed taxonomic significance, from a group of large Cretaceous pterosaurs whose complete anatomy remains unknown.