Spinacanthidae is an extinct prehistoric
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of
tetraodontid bony fish that lived from the
Lutetian
The Lutetian is, in the geologic timescale, a stage or 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 is sometimes referred to as the ...
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 by ...
of
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
Monte Bolca.
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 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
Monte Bolca. Because of their similarity to
boxfish
Ostraciidae is a family of squared, bony fish belonging to the order Tetraodontiformes, closely related to the pufferfishes and filefishes. Fish in the family are known variously as boxfishes, cofferfishes, cowfishes and trunkfishes. It contains ...
, and due to their close relation to modern-day
triggerfish
Triggerfish are about 40 species of often brightly colored fish of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacifi ...
, spinacanthids may have preyed on shellfish and small fish.
See also
* ''
Eospinus'', another close relative from the Earliest Eocene of
Turkmenistan
Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the sout ...
* ''
Eolactoria
''Eolactoria sorbinii'' is an extinct prehistoric boxfish that lived during the Lutetian epoch of the middle Eocene, in Monte Bolca. It had two pairs of long spines, one over each eye, and one pair beneath the anal and caudal fins, arranged ...
'', another extinct tetraodontid from Monte Bolca
* ''
Proaracana'', another extinct tetraodontid from Monte Bolca
*
Prehistoric fish
The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull and the vertebral column, leading to the first craniates and vertebrates. The first fis ...
*
List of prehistoric bony 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)
Prehistoric ray-finned fish families
{{tetraodontiformes-stub