Spinacanthidae is an extinct prehistoric

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of tetraodontid

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

that lived from the

Lutetian The Lutetian is, in the geologic timescale, a stage (stratigraphy), stage or age (geology), age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

Monte Bolca Monte Bolca is an Ypresian, Early Eocene-aged geologic site located near Verona, Italy, Verona, Italy. A ''Konservat-Lagerstätte'', it contains an extremely well-preserved and diverse marine biota, including the most diverse fish fauna of any Ce ...

. In life, either genus would have resembled a somewhat-flattened boxfish with five massive spines along the anterior-dorsal side, with the longest spine directly above the forehead, and the shortest spine directly in front of the dorsal fin. ''Protobalistum'' is distinguished from its close,

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

relative, '' Spinacanthus'', in that its scales are large, and form a sort of armor. In ''Spinacanthus'', the individual scales are relatively small, and do not touch each other. ''Protobalistum'' and ''Spinacanthus'' were a part of the ecosystem of the lagoon that became

. Because of their similarity to

boxfish Ostraciidae or Ostraciontidae is a family of squared, Actinopterygii, bony fish belonging to the order Tetraodontiformes, closely related to the pufferfishes and filefishes. Fish in the family are known variously as boxfishes, cofferfishes, cowfi ...

, and due to their close relation to modern-day

triggerfish Triggerfish are about 40 species of often brightly colored marine ray-finned fishes belonging to the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest speci ...

, spinacanthids may have preyed on shellfish and small fish.

References

A remarkable new genus of Tetraodontiform fish with features of both Balistids and Ostraciids from the Eocene of Turkmenistan
(contains a brief discussion and description of Spinacanthidae) Ostracioidea Prehistoric ray-finned fish families {{paleo-tetraodontiformes-stub

See also

References