''Harpagofututor'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of eel-like

cartilaginous fish Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeleto ...

from the Early

Carboniferous The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the Paleozoic era (geology), era that spans 60 million years, from the end of the Devonian Period Ma (million years ago) to the beginning of the ...

( Mississippian). It is primarily known from complete specimens discovered in the

Bear Gulch Limestone The Bear Gulch Limestone is a limestone-rich Lens (geology), geological lens in central Montana, renowned for the quality of its marine fossils from the late Mississippian (geology), Mississippian subperiod, about 324 million years ago. It is expo ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, as well as an isolated tooth from Whitrope, Scotland.

Discovery and taxonomy

''Harpagofututor'' was first described in 1982, from several complete specimens discovered in the Bear Gulch Limestone of Montana by

Adelphi University Adelphi University is a private university in Garden City, New York, United States. Adelphi also has centers in Downtown Brooklyn, Hudson Valley, and Suffolk County in addition to a virtual, online campus for remote students. As of 2019, it had ...

palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

Richard Lund.Lund, Richard. "Harpagofututor volsellorhinus New Genus and Species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean), and Their Sexual Dimorphism," ''Journal of Paleontology'', Vol. 56, No. 4, July 1982, pp. 938-958. There is only one named species, ''H. volsellorhinus'', which was described by Lund in 1982. A single specimen of indeterminate species is also known from a single tooth plate discovered in Whitrope, Scotland. The genus is placed in the family Chondrenchelyidae, which are suggested to be members of

Holocephali Holocephali (Sometimes spelled Holocephala; Romanization of Greek, Greek for "complete head" in reference to the fusion of Palatoquadrate, upper jaw with the rest of the skull) is a Subclass (biology), subclass of Chondrichthyes, cartilaginous fi ...

, with their closest living relatives being

chimaeras Chimaeras are Chondrichthyes, cartilaginous fish in the order (biology), order Chimaeriformes (), known informally as ghost sharks, rat fish (not to be confused with rattails), spookfish, or rabbit fish; the last two names are also applied to B ...

Description

Like the other only well known member of Chondrenchelyidae, '' Chondrenchelys'', ''Harpagofututor'' had a long, elongate eel-like body (with known specimens ranging in length from ) with a long upper medial fin running along the upper surface of the body without a fin spine. The skull tapered towards the front end, becoming very narrow near its apex. The mouth has pairs of tooth plates in the upper and lower jaws, comparable to those of living chimaeras, which were triangular in shape. The tooth plates when unworn have a ridged texture, with the ridges being separated by small knobs. The heads of males had unusual paired forked hollow structures growing from the top of the head, known as ethmoid or cephalic

clasper In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's ...

s, formed from 3 rods, one basal rod (which is partially calcified) attached to the skull to which two other rods (which were covered in denticles) articulated, with the structures apparently being able to rotate on a ball-and socket joint where they joined the skull. They are thought to have been used during mating. These structures, which are considerably longer than the skull itself, are apparently unique to ''Harpagofututor'' and not found in ''Chondrenchelys''.

Ecology

The tooth plates of ''Harpagofututor'' are thought to have been used to crush prey. ''Harpagofututor'' is suggested to have given live birth, with newborn juveniles being proportionally large and morphologically nearly identical to adults. Finds as stomach contents suggest that ''Harpagofututor'' was preyed upon by the eel-like

elasmobranch Elasmobranchii () is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks ( division Selachii), and batomorphs (division Batomorphi, including rays, skates, and sawfish). Members of this subclass are characterised by h ...

'' Thrinacodus''.

Sources

*

* ''Aquagenesis: The Origin and Evolution of Life in the Sea'' by Richard Ellis * ''The Rise of Fishes: 500 Million Years of Evolution'' by John A. Long

References

{{Taxonbar, from=Q3783458 Monotypic prehistoric cartilaginous fish genera Carboniferous cartilaginous fish Mississippian fish of North America Bear Gulch Limestone