New shark glows in the dark


Scientists have described a new species of shark which emits green light from its belly.

Jayna Schaaf-DaSilva and David Ebert of the Pacific Shark Research Center in California named the new species Etmopterus burgessi in a paper in the journal Zootaxa.

The lanternshark was described from four specimens collected in deepwater trawls in the western North Pacific off Taiwan.

The new shark is a member of the Squaliformes family Etmopteridae and is said to closely resemble members of the Etmopterus lucifer group in having longitudinal rows of dermal denticles.

Schaaf-DaSilva and Ebert said that the new lantern shark differs from other members of the genus based on a number of morphological characters:

"Snout width, gill slit length, caudal peduncle length, second dorsal fin height, the arrangement of flank and caudal markings, tooth morphology and the presence or absence of dermal denticles.

"The new species has a broader snout and gill length and proportionally longer than other western North Pacific Etmopterus species.

"Proportionally, E. burgessi has a shorter second dorsal fin height and caudal peduncle length than other Etmopterus species. In addition, both the second dorsal fin and ventral snout surface of E. burgessi have conspicuous dermal denticles. A final distinguishing character of E. burgessi is the flank marking, which resembles E. lucifer."

The Etmopterus genus contains around 31 valid species, of which around half have been discovered in the past 20 years.

Lanternsharks are typically very small and have luminescent photophore organs - normally on the belly - that produce a bright green light. All species live in very deep water where surface daylight cannot penetrate.

One species, E. perryi, may be the world's smallest shark species, being fully grown at around 15-20cm/6-8".

For more details on the new shark species see the paper: Schaaf-DaSilva JA and DA Ebert (2006) - Etmopterus burgessi sp. nov., a new species of lanternshark (Squaliformes: Etmopteridae) from Taiwan. Zootaxa 1373: 53-64 (2006).