- kingdomAnimalia
- ›phylumChordata
- ›classHolocephali
- ›orderChimaeriformes
- ›familyChimaeridae
- ›genusHydrolagus
Galapagos Ghostshark
Hydrolagus mccoskeri Barnett, Didier, Long & Ebert, 2006
Also calledGalápagose merijänes (est) · Quimera-de-Galápagos (por)
First described in: Barnett, L.A.K.; Didier, D.A.; Long, D.J.; Ebert, D.A. (2006). <i>Hydrolagus mccoskeri</i> sp. nov., a new species of chimaeroid fish from the Galápagos Islands (Holocephali: Chimaeriformes: Chimaeridae). Zootaxa 1328:27-38.
The Galápagos ghostshark (Hydrolagus mccoskeri) is a chimaera species in the family Chimaeridae, likely endemic to the Galápagos Islands. It was discovered by John E. McCosker in 1995 and described in 2006, scientifically named in honor of McCosker. This chimaera has a brown compressed, elongate body. The holotype and paratype of the species, both juvenile females, had a total length of 38.1 centimetres (15.0 in) and 22.7 centimetres (8.9 in), respectively. It lives in rocky habitats close to the sea floor, in waters about 395–510 metres (1,296–1,673 ft) deep. It is listed as least concern on the IUCN Red List.
Descriptions from checklists and floras indexed by GBIF
materials_examined
- 1 specimen. CAS 86558, juvenile female, 381 mm TL, 274 mm PCL, 211 mm BDL, southeast of San Cristobal Island, Galapagos (01 ° 5.981 ’ S, 89 ° 12.235 ’ W), 396.24 m, collected by J. E. McCosker (CAS), R. Grant Gilmore (HBOI) and Bruce Robison (MBARI), 17 Nov. 1995 (JSL dive 3934)
A new species of chimaeroid, Hydrolagus alphus sp. nov. (Chimaeriformes: Chimaeridae) from the Galapagos Islands.
biology_ecology
Individuals were found alone or in groups along steep slopes, within a few meters of the seafloor. Habitat was composed of igneous boulders, cobbles, and pebbles. The observed bathymetric range is shallow compared to many other Hydrolagus, and may reflect incomplete deep-water sampling in the region. However, the two most similar congeners in morphology and distribution, H. novaezealandiae and H. colliei, are also found in relatively shallow depths (Eschmeyer et al. 1983; Anderson et al. 1998), suggesting that the observed depth distribution of H. mccoskeri may accurately represent its true bathymetric range.
Hydrolagus mccoskeri sp. nov., a new species of chimaeroid fish from the Galápagos Islands (Holocephali: Chimaeriformes: Chimaeridae).
description
Description. Holotype and paratype morphometric measurements are presented in Table 1. Head small (HDL 31 - 32 % BDL), with rounded, short snout and large eyes (EYL 9 - 13 % BDL). Body depth (dorso-ventral height of body at a given distance from snout tip) remains similar from head to origin of pelvic fins, from which point it rapidly tapers distally to pelvic fin tips (when depressed posteriorly), subsequently transitioning into a whiplike tail. Skin firm and robust, not deciduous as in some other Hydrolagus (Didier 2002). Post-anal pad present, but inconspicuous in the juvenile type specimens. Tooth plates light yellow in preserved specimens, with white tritors. Vomerine tooth plates small and incisor-like with 5 tritors visible on the right and 5 - 6 on the left. Palatine tooth plates with 2 - 3 tritors along the oral surface originating at the posterior edge and terminating prior to the anterior edge. Small protrusions are present along the anterior labial edge. Mandibular tooth plates incisor-like and large (three times wider than vomerine tooth plates), with 5 tritors per side. Lateral line canals on head are open grooves with especially wide dilation of canals on the snout.
Hydrolagus mccoskeri sp. nov., a new species of chimaeroid fish from the Galápagos Islands (Holocephali: Chimaeriformes: Chimaeridae).
diagnosis
Diagnosis. A species of Hydrolagus distinguished from congeners by the following combination of characters: head small with short, blunt snout; second dorsal fin only slightly indented along its length; preopercular and oral lateral line canals branching from the same node off the infraorbital canal and sharing a short common branch; dorsum medium brown with numerous narrow, sharply delineated irregular circular and elongate white blotches; ventrum white to tan with extremely fine brown mottling.
Hydrolagus mccoskeri sp. nov., a new species of chimaeroid fish from the Galápagos Islands (Holocephali: Chimaeriformes: Chimaeridae).
From Wikipedia (CC BY-SA), quoted section by section
Description
This ghostshark has a compressed, elongate body, which thins out to its tail. It is medium-brown in color, with a lighter underside and a darker upperside. Most of its fins are dark, including its two dorsal fins, while its lower tail is white. It is covered with blotches of white, which can be circular, narrow, or elongate in shape. Of the two type specimens, the holotype had a total length (TL) of 38.1 centimetres (15.0 in) and a body length (BDL) of 21.1 centimetres (8.3 in), while the paratype was slightly smaller, with a TL of 22.7 centimetres (8.9 in) and BDL of 10.7 centimetres (4.2 in). The species has smooth skin and lacks scales. It has two dorsal fins, the first of which is upright and triangular and the second of which is longer and lower. The end of its tail fin has a "whip-like" fiber at the end of it and it lacks an anal fin. It has three pairs of plates inside of its mouth for teeth. Males have multi-pointed external sex organs. Other characteristics of the species include a small head, a round snout, large green eyes, and nostrils linked to its mouth with a flap-covered groove.
Range & habitat
H. mccoskeri is likely endemic to the Galápagos Islands in the southeastern Pacific Ocean. When the species was described in 2006, there were nine recorded instances of it at four locations: Fernandina Island, Española Island (paratype), Marchena Island, and San Cristóbal Island (holotype). The species' population is unknown. Most fisheries in its range operate in shallower waters than its preferred depth; no deepwater fisheries are present in its range. Its habitat cannot be trawled in because it is too rocky. Its entire range is within the Galápagos Marine Reserve; in the reserve, industrial fishing is prohibited, but artisanal fishing is still allowed. Fishers frequently violate these regulations, fishing illegally, and they are often not prosecuted for such activities. The International Union for Conservation of Nature (IUCN) said that the species requires further studying of its population and threats before receiving an assessment. It is listed as least concern on the IUCN Red List.
== References ==
What it does
The Galápagos ghostshark has been observed to occur on steep slopes, in areas containing stones and boulders with dispersed sand and silt. The nine specimens in the original description were found in depths of 396.25–505.97 metres (1,300.0–1,660.0 ft). This is a shallower range than most species in Hydrolagus, but the two most closely related species to the Galápagos ghostshark – the spotted ratfish (Hydrolagus colliei) and the dark ghostshark (Hydrolagus novaezealandiae) – do live in shallower depths. The specimens were found close to the sea floor, in groups or alone. The species is a carnivore, feeding on aquatic worms, mollusks, and crustaceans.
Where it has been recorded
Recorded sightings
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geo-referenced records in GBIF, from museums, herbaria and field observers.
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In the stacks
Searching the stacks…
Every page naming Hydrolagus mccoskeri in the Biodiversity Heritage Library →
From the GBIF Backbone Taxonomy and occurrence records (GBIF.org), with Wikipedia and the Source Library. GBIF species 5215456.