The Saddled swellshark (Cephaloscyllium variegatum) is a species of catshark belonging to the family Scyliorhinidae, endemic to northeastern Australia. They are found on continental slopes between 125-1,936 feet. They have a beautiful saddled pattern, which allows it to become perfectly camouflaged within its environment. Like other members of its genus, they can inflate their stomachs in an effort to frighten potential predators.
Family: Scyliorhinidae – Catsharks
Genus: Cephaloscyllium
Species: variegatum
Phylum– Chordata
Class– Chondrichthyles
Common Name– Ground Sharks
Family– Scyliorhinidae
Common Name– Catsharks
Genus– Cephaloscyllium
Species– variegatum
Status: IUCN Red List NEAR THREATENED
Average Size and Length: The smallest known free-swimming specimen measured 17 cm/ 6.7 inches. Mature males measure around 55 cm/1.8 feet. The maximum recorded is over 70 cm/2.3 feet: 74 cm/2.4 feet.
Current Rare Mythical Sightings: In 1994, Commonwealth Scientific and Industrial Research Organisation (CSIRO) chief researchers Peter Last and John Stevens recognized five undescribed swellsharks in Australian waters. Later investigation revealed that the forms provisionally named Cephaloscyllium “sp. B” and “sp. C” may represent clinal variants of a single species, which was described by Peter Last and William White in a 2008 CSIRO publication. The specific epithet variegatum comes from the Latin word for “various”, and refers to the large amount of color variation within this species. The type specimen is 68 cm/27 inches long adult male, collected from east of Newcastle, New South Wales.
Teeth and Jaw: The mouth is large. The teeth have 3-7 cusps near the symphysis of the upper jaw. The tooth rows number 68–82 in the upper jaw and 68–80 in the lower jaw. The very small teeth have three cusps, with the central one the longest and sometimes 1–2 additional lateral cusplets. In females the central cusp is smaller than in males. There are no furrows at the corners of the mouth, and the upper teeth are exposed when the mouth is closed.
Head: The head is slender, short, broad and flattened. The head is between 9.4-10.5% of the total length in height. The snout is broadly rounded, with the nostrils preceded by laterally expanded flaps of skin that do not reach the large mouth. The slit-like, cat-like eyes are positioned high on the head and followed by tiny spiracles. There are ridges over the eyes. The prenarial is between 4.4-5.0% total length, in length. The length of preorbital snout is between 1.5-1.7 times the prenarial length. The snout-vent length long, between 50.5-52.9% of the total length. The nostril is 2.4-2.6% of the total length in width. The eye-spiracle space is wide, between 0.8-1.3% of the total length.
Denticles: The body is densely covered by minute dermal denticles, each shaped like an arrowhead and having a median ridge. The flank dermal denticles are mainly unicuspidate. The back does not have greatly enlarged dermal denticles.
Tail: The caudal fin is deep, with a distinct lower lobe and a strong ventral notch near the tip of the upper lobe.
Demographic, Distribution, Habitat, Environment and Range: The Saddled swellshark can be found in northeastern Australia on continental slopes between 125-1,936 feet. They are considered sub-tropical, bathypelagic.
Ram-Suction Index: More than likely high on the suction side of the index.
Aesthetic Identification: The Saddled swellshark is a small catshark, but robustly built. The fourth and fifth gill slits lie over the pectoral fin bases and are shorter than the first three. It is medium brownish or greyish with obvious dark saddles. There are usually 5 in front of the dorsal fins. Blotches are usually absent from the sides. The fin margins are sometimes pale. The ventral side is pale. The stomach is inflatable. The pectoral fins are large and broad, with rounded margins. Both dorsal fins are close together. The first dorsal fin is fairly angular and originates over the middle of the pelvic fin bases. The second dorsal fin is much smaller and lower than the first, originating behind the anal fin origin. The pelvic fins are small, with elongate, relatively short claspers in males. It is 2.9-3.3 in prepectoral length, and 6.4-7.2 in prepelvic length. The pectoral fins are large, the height is between 12.9-13.2% of the total length. The posterior margin length is between 10.4-12.1% of the total length. The anal fin is between 3.5-4.1% of the total length, in height. The anal-caudal space is between 4.5-5.7%, precaudal is between 76-78% of total length, in length. The interdorsal space is between 6.5-8.0% of the total length. The anal fin is substantially larger and deeper than the second dorsal fin. The trunk width is between 14.5-17.1% of the total length.
Biology and Reproduction: They are oviparous, with its eggs contained in smooth, brownish egg cases about 7 cm/2.8 inches long. Each egg case is thick and rounded, with flanged lateral margins and a pair of horns at each end, which support very long, coiled tendrils. Not much else is known.
The vertebral centra is between 116-124.
Behavioral Traits, Sensing and Intelligence: Like other members of its genus, the Saddled swellshark has an inflatable stomach that it can fill with water (or air on land) to increase its girth, in an attempt to ward of predators.
Speed: More than likely slow and sluggish.
Saddled Swellshark Future and Conservation: They are near threatened because its limited range. Currently there is little fishing in its range, but could be vulnerable, so it is listed as near threatened.
Saddled Swellshark Recorded Attacks on Humans: Not a threat to humans.