Tylosurus crocodilus

Crocodile longtom
Tylosurus crocodilus
Tylosurus crocodilus, Banda Aceh, Indonsia, Photo: Ian Shaw
Tylosurus crocodilus
Tylosurus crocodilus, Raja Ampat, Indonesia, Photo: Andrew Green
Tylosurus crocodilus
Tylosurus crocodilus, Bali, Indonesia, Photo: Ian Shaw
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Tylosurus crocodilus
Tylosurus crocodilus
Tylosurus crocodilus


Temperate Australasia, Temperate northern Atlantic, Tropical Indo-Pacific


A large and robust longtom, characterised by a wavy tail margin that has a noticeably longer lower than upper lobe. Similar Strongylura incisa has a flatter tail margin. This species almost impossible to distinguish from the Australian endemic T. gavialoides in the field, and so the Australian occurrence locations on this map should be considered in combination with those shown on the page for that species.


Max Size: 150 cm

Sea Temperature Range: 17.2-31.5°C

Depth: 0-13 m

Habitat Generalization Index: 0.72

Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.

Conservation and Rarity

IUCN Status: Not Evaluated

Occurrence: Infrequent (1.5% of sites)

Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed

Abundance: Few (4 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.