Tomistoma cairense is an extinct species of gavialoid crocodilian from the Lutetian stage of the Eocene era.

[4] Tomistoma cairense did not have a Maxilla process within their lacrimal gland, whereas all extant (living) crocodilians do.

[5] Below is a cladogram based morphological studies comparing skeletal features that shows Tomistoma cairense as a member of Tomistominae, related to the false gharial:[6] Crocodylinae Xaymacachampsa† Megadontosuchus† Kentisuchus† Maroccosuchus† Dollosuchoides† Thecachampsa† Penghusuchus† Toyotamaphimeia† Tomistoma cairense† Maomingosuchus† Tomistoma schlegelii False gharial Gavialosuchus† Tomistoma lusitanicum† Paratomistoma† Tomistoma coppensi† Based on morphological studies of extinct taxa, the tomistomines (including the living false gharial) were long thought to be classified as crocodiles and not closely related to gavialoids.

[7] However, recent molecular studies using DNA sequencing have consistently indicated that the false gharial (Tomistoma) (and by inference other related extinct forms in Tomistominae) actually belong to Gavialoidea (and Gavialidae).

[8][9][10][11][12][13][14] Below is a cladogram from a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data that shows Tomistoma cairense as a gavialoid, more basal than the last common ancestor to both the gharial and the false gharial:[13] Gavialis gangeticus Gharial Gavialis bengawanicus† Gavialis browni† Gryposuchus colombianus† Ikanogavialis† Gryposuchus pachakamue† Piscogavialis† Harpacochampsa† Toyotamaphimeia† Penghusuchus† Gavialosuchus† Tomistoma lusitanicum† Tomistoma schlegelii False gharial Tomistoma cairense† Dollosuchoides† Maroccosuchus† Paratomistoma† Kentisuchus† Tomistoma cairense may need to be reclassified to a new genera, as studies have shown that its inclusion makes Tomistoma out to be paraphyletic.