Common Name
Gulf Pocket Shark
Year Described
Grace, Doosey, Denton, Naylor, Bart & Maisey, 2019
Identification
Teeth: 21 upper, 31 lower. Upper teeth slender and erect. Lower teeth larger and triangular
Vertebrae: 73 total
Body elongate, cylindrical and strongly tapering posteriorly. Body thickest at head. Head large. Snout long and blunt. Nostrils at tip of snout. Mouth small with upper labial furrows, long post-oral grooves, and thick fringed lips. Eyes large. Five gill slits very short. Two dorsal fins closely spaced (separated by about length of fin). First dorsal fin rounded and placed just anterior to pelvic fin. Second dorsal fin a little longer and lower than first dorsal fin, inserted behind pelvic fin edge. Pectoral fin moderate and squared off. Pelvic fin well posterior (right under rear of first dorsal) and similar in size to first dorsal. Anal fin absent. Caudal fin with distinct subterminal notch, extended upper lobe and and pronounced lower lobe. A pit organ (pocket) above pectoral fin base releases luminescent fluid. Skin rough. Denticles small and arrowhead shaped.
Color
Body uniformly gray-brown. Fin edges light. Bioluminescent glands present on body as pale circles. Exudes blue luminescent fluid from pocket gland above pectoral fin.
Size
Single male specimen measures 14.2cm TL and is immature.
Habitat
Captured in a midwater trawl surveying depths between 5-580m over 3000m abyssal plains.
Range
Only known from one specimen captured in the central Gulf of Mexico.
References
Ebert, D.A., Dando, M., & S. Fowler. 2021. Sharks of the World. Princeton University Press. 607 pp.
Grace, M.A., Doosey, M.H., Denton, J.S., Naylor, G.J.P., Bart Jr., H.L & J.G. Maisey. 2019. A new Western North Atlantic Ocean kitefin shark (Squaliformes: Dalatiidae) from the Gulf of Mexico. Zootaxa, 4619(1), 109-120.
Other Notes
The only other known Mollisquama sp. is M. parini from the Nazca Ridge of Chile which is known from one 40cm specimen. The Atlantic species is likely able to reach a similar size. According to Grace et al. (2019) it differs from M. parini “…in having a putative pit organ centrally placed just posterior to the lower jaw margin, photophores irregularly distributed along many areas of the body, a series of 16 ventral-abdominal photophore aggregations, upper teeth without a labial-surface ridge (M. parini has a labial-surface ridge), and lower teeth with a weak or absent basal sulcus (M. parini has a deep basal sulcus). The distinguishing external features the pit organ and photophore aggregations were clearly discernable when the new species was captured (Grace et al. 2015) and after preservation. These features were not reported as present on M. parini."