Blurred lanternshark

Japanese ichthyologists Shigeru Shirai and Hiroyuki Tachikawa described the blurred lanternshark in a 1993 article in the scientific journal Copeia, as part of a taxonomic revision of the Etmopterus pusillus species group. Shirai and Tachikawa found that the species group comprises the smooth lanternshark (E. pusillus) and a hitherto unrecognized second species, which they named E. bigelowi in honor of Henry B. Bigelow (who, along with William C. Schroeder and Stewart Springer, first described the blurred lanternshark in 1955, but did not see it as being separate from E. pusillus). This species may also be referred to as the smooth lanternshark or the blurred smooth lanternshark. ==Distribution and habitat==

Blurred lanternsharks have been caught around the world over continental and insular shelves and slopes, submarine ridges, and seamounts. Like many other lantern sharks, adults are found deeper than juveniles. ==Description==

Growing to a length of at least , the blurred lanternshark has a slender body, large head, and short tail. The snout is wedge-shaped and slightly flattened, tapering to a point. The nostrils are large, with short flaps of skin in front. The eyes are oval in shape with a deep anterior notch in the orbit. The mouth has long furrows at the corners that extend halfway to the first of five gill slits. There are 19–24 tooth rows in the upper jaw, each with a narrow central cusp flanked by 2–4 pairs of smaller cusplets, increasing in number with age in males over long. There are 25–39 tooth rows in the lower jaw, each tooth with a smooth-edged, knife-like cusp and their bases interlocked to form a single cutting surface; the teeth of males over long and females over long become more erect with age. The blurred lanternshark is very similar to the smooth lanternshark, but is larger and can be reliably differentiated by the number of turns in the spiral valve intestine (16–19 versus 10–13). ==Biology and ecology==

The diet of the blurred lanternshark consists of squid, smaller dogfish sharks, lanternfishes, and fish eggs. Reproduction is ovoviviparous, with developing embryos being sustained by a yolk sac and being born live at a length of . Males attain sexual maturity at around long, and females at long. ==Human interactions==

Blurred lanternsharks are harmless and of no commercial significance, but may be caught and discarded by deepwater fisheries. Because of its wide distribution and the lack of evidence for heavy fishing mortality, the IUCN has assessed this species as of Least Concern. ==References==