| Figaro | |
|---|---|
 | |
| Australian sawtail catshark (F. boardmani) | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Division: | Selachii |
| Order: | Carcharhiniformes |
| Family: | Pentanchidae |
| Genus: | Figaro Whitley, 1928 |
| Type species | |
| Pristiurus (Figaro) boardmani Whitley, 1928 | |
Figaro is agenus ofshark, and part of thefamilyPentanchidae, the deepwater catsharks. Until 2008,Figaro was generally considered to be asubgenus ofGaleus, the sawtail catsharks. The two known species are found offAustralia, inhabiting deep, offshore waters on or near the bottom.Figaro contains small, slender, firm-bodied sharks that bear distinctive crests of enlarged, spinydermal denticles along the dorsal and ventral edges of their shortcaudal fins. Thecaudal peduncle is relatively long, such as that theanal and caudal fins are some distance apart. In adult males, the inner margins of thepelvic fins are fused together to form a subtle "apron" over theclaspers.F. boardmani is apredator of fishes,crustaceans, andcephalopods, and isoviparous; less is known about theF. striatus. Both are harmless and are of no economic importance.
Figaro was coined as asubgenus ofPristiurus by AustralianichthyologistGilbert Percy Whitley in a 1928 issue of thescientific journalRecords of the Australian Museum, to contain his newly described speciesP. boardmani.[1] In 1908,Henry Weed FowlersynonymizedPristiurus with the genusGaleus.[2] Though Whitley elevatedFigaro to the rank of full genus in 1939,[3] most authors continued to regardFigaro as a subgenus ofGaleus.[4] In 1983, Yuan-Ting Chu and colleagues referencedFigaro to containGaleus boardmani,Dichichthys melanobranchus (=Parmaturus melanobranchus), andF. piceus (=P. melanobranchus). However, it is uncertain whether they intended to resurrectFigaro or were simply unaware of its synonymy withGaleus, and their use of the ventral denticle crest to define the genus posed taxonomic problems.[5][6] In 2008,Commonwealth Scientific and Industrial Research Organisation (CSIRO) researchers Daniel Gledhill, Peter Last, and William White resurrectedFigaro with additional defining characters, to containF. boardmani and the new speciesF. striatus. The genus has since been generally accepted as distinct.[4]
One of the key characteristics ofFigaro, the ventral crest of denticles on thecaudal fin, is also present in several species of the genusParmaturus, as well as theSpringer's sawtail catshark (G. springeri) and themouse catshark (G. murinus).[6]Figaro also closely resembles the genusAsymbolus in severalmorphological characters, including the fusion of thepelvic fin inner margins in adult males. More research is required to elucidate the relationships betweenFigaro,Galeus,Asymbolus, andParmaturus.[4]
BothFigaro species areendemic toAustralian waters,F. boardmani in the south andF. striatus in the northeast. They are deepwater species found on or near thesea floor, inhabiting the outercontinental shelf and uppercontinental slope.[7]
The largerFigaro species,F. boardmani, reaches 61 cm (24 in) long, while the smallerF. striatus reaches 42 cm (17 in) long. Members of this genus closely resembleGaleus, with firm, slender bodies and short heads. The eyes are horizontally oval and equipped with rudimentarynictitating membranes (protective third eyelids); a narrow ridge is found beneath each eye and a tinyspiracle behind. The anterior rims of the nostrils are enlarged into triangular flaps. The mouth is wide, with relatively short furrows at the corners, and contains small multi-cusped teeth. There are five pairs ofgill slits.[4][8]
The first and seconddorsal fins are similar in size and shape, and are placed mostly behind thepelvic andanal fins respectively. The space between the dorsal fins is much longer than the length of either dorsal fin base. Thepectoral fins are short and broad, while the pelvic andanal fins are low with rather long bases. The pectoral, pelvic, and anal fins are proportionally smaller than inGaleus. UnlikeGaleus species, adult males have a slight "apron" formed by the fusion of the pelvic fin inner margins; the apron partially covers theclaspers, which taper towards the tip. Thecaudal peduncle is long, with the anal andcaudal fins well-separated. The caudal fin is short, with a small lower lobe and a ventral notch near the tip of the upper lobe. The body and fins are densely covered by tiny, overlappingdermal denticles. In addition, there are enlarged denticles that form prominent saw-like crests on both the dorsal and the ventral edges of the caudal fin. The dorsal coloration consists of dark saddles along the back and tail, which are wider inF. boardmani and thinner inF. striatus. The two species also differ in variousmorphometric characters, such as in the relative size of the eye.[4]
The natural histories ofFigaro species are poorly known.F. boardmani feeds mostly on fishes,crustaceans, andcephalopods, and has anoviparous mode of reproduction.[9][10]
NeitherFigaro species is commercially important or significantly threatened by fishing activity, thoughF. boardmani forms a regular component ofbottom trawlbycatch incommercial fisheries within its range. TheInternational Union for Conservation of Nature (IUCN) has listedF. boardmani asLeast Concern andF. striatus asData Deficient.[9][10] Like other catsharks,Figaro species pose no danger to humans.[7]
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