The Shortfin Smooth lanternshark (Etmopterus joungi) is a shark of the family Etmopteridae found off the northeastern coast of Taiwan, at depths of between 984-1,805 feet. It was classified by Knuckey, Ebert & Burgess in 2011.
Family: Etmopteridae – Lantern Sharks
Genus: Etmopterus
Species: joungi
Phylum– Chordata
Class– Chondrichthyles
Subclass– Elasmobranchii
Common Name– Dogfish Sharks
Family– Etmopteridae
Common Name– Lantern Sharks
Genus– Etmopterus
Species– joungi
Status: IUCN Red List NOT EVALUATED
Average Size and Length: The maximum recorded length of a male has been 40.6 cm/1.3 feet and the maximum recorded length of a female is 45.6 cm/1.5 feet.
Teeth and Jaw: The Shortfin Smooth lanternshark has a broad and strongly arched mouth. The upper teeth differ from lower teeth with each tooth in the first functional row with a single median cusp and flanked by 1-2 lateral cusplets on either side. The lower teeth are in a single series, forming blade-like edges with slender, non-erect cusps. The upper tooth counts numbering 27 (25-30) and the lower tooth counts numbering 42 (33-36).
Comparisons: Etmopterus joungi possesses an upper jaw dentition with a relatively slender medial cusp and robust lateral cusplets (but not as large as the medial cusp) on either side. Etmopterus pusillus generally possesses an upper jaw dentition with a slender medial cusp with slender lateral cusplets, whereas E. bigelowi generally possesses an upper jaw dentition with a significantly more robust medial cusp with robust lateral cusplets on either side. The lower jaw dentition of E. joungi is also different in that the cusps are significantly more oblique and relatively slender than those found in E. pusillus and E. bigelowi of similar sizes and sexes.
Head: The Shortfin Smooth lanternshark has a short preoral snout of 8.0% of the total length (8.2-8.7). It has a relatively short head being 15.9% of the total length (15.3-16.0).
Denticles: The dermal denticles are truncate low, with block-like crowns, irregularly arranged over the majority of the body, extending onto the dorsal fins.
Tail: The caudal fin short is.
Demographic, Distribution, Habitat, Environment and Range: The Shortfin Smooth lanternshark is found off the northeastern coast of Taiwan, at depths of between 984-1,805 feet. They are pelagic-oceanic occurring along the upper continental slope.
Aesthetic Identification: There are a number of characteristics that make the Shortfin Smooth Lanternshark unique. It is dusky grey dorsally and black to dark grey ventrally in life. The pectoral to the pelvic fin space is large, comprising 29.0% of the total length (25.3-27.30). There are very narrow pectoral fins, the posterior portion is square-shaped. The posterior margin is acutely angular at the anterior and inner margins, with no expanded corners of fins. The second dorsal fin is located posteriorly along body, and the second dorsal fin spine is long and strongly recurved, 0.5 (0.3-0.5) into dorsal fin height. The interdorsal space is about three times the distance between the first dorsal fin spine origin and pectoral fins. There is an inconspicuous suprapelvic flank marking lacking the posterior branch. The dorsal caudal fin margin is short, being 15.4% of the total length (15.3-19.4). The posterior end of the lateral line becomes an open groove, with the ventral edge darkly colored.
Biology and Reproduction: The monospondylous vertebrae count is 48 (38-41). The diplospondylous vertebrae count is 17 (21-24). The dorso-caudal vertebrae count is 24 (22-25). The total vertebrae count is 89 (84-88). The spiral valve has 11 turns.
Their reproduction is unknown, but presumably ovoviviparous. Sexual maturity in males likely achieved between 31.9 and 40.6 cm, and in females, larger than 45.6 cm.
A cymothiod isopod Elthusa raynaudi was found attached to the roof of the mouth of the holotype (normally occurs in the gill chambers of fishes).
Behavioral Traits, Sensing and Intelligence: Unknown.
Shortfin Smooth Lanternshark Future and Conservation: Not enough data to evaluate. They have been caught by bottom trawlers deeper than 300 m.
Shortfin Smooth Lanternshark Recorded Attacks on Humans: Not a threat to humans.
Knuckey, J.D.S., D.A. Ebert and G.H. Burgess, 2011. “Etmopterus joungi n. sp., a new species of lanternshark (Squaliformes: Etmopteridae) from Taiwan”. Aqua Int. J. Ichthyol. 17(2): 61-72.