Gollum Compagno

Last, Peter R. & Gaudiano, Joe P., 2011, Gollum suluensis sp. nov. (Carcharhiniformes: Pseudotriakidae), a new gollumshark from the southern Philippines, Zootaxa 3002, pp. 17-30 : 18

Genus Gollum Compagno

Gollum Compagno, 1973 , Proc. California Acad. Sci., ser. 4, 39(14): 264. Type species: Triakis attenuata Garrick, 1954 , by original designation.

Definition. Distinctive carcharhiniform sharks with a firm to soft and very slender body; short, bell-shaped head; long, flattened snout, horizontal length 7–9% TL; small spiracles, 4–10 times in eye length; angular mouth with very small multicuspidate teeth (81–114 rows in jaws); dental bands comb-like near jaw angle; moderately elongate labial furrows (lower furrow subequal to or greater than length of incurrent aperture of nostril); short anterior nasal flaps (subequal to length of excurrent aperture of nostril); broad internarial space, 1.5–1.9 times nostril width; no dermal gill rakers or large oral papillae; first dorsal fin not long-based and keel-like; interdorsal ridge present; first dorsal-fin base well forward of the pelvic-fin base; second dorsal fin taller and more upright than first dorsal fin; anal-fin origin well behind second dorsal-fin origin; free rear tip of anal fin under or slightly forward of second dorsal-fin insertion; no precaudal pits; caudal peduncle relatively elongate, 8–10% TL; dorsal caudal margin short, 19–23% TL, not undulated, instead with a raised scaly ridge; enlarged lateral scales of caudal ridge semicircular, horizontally directed; coloration simple, darker dorsally than ventrally; monospondylous centra 44–53, diplospondylous centra 107–113, total centra 151–166.

Species. Gollum attenuatus ( Garrick, 1954) , G. suluensis sp. nov.

Remarks. The erection and initial placement of Gollum in the family Proscylliidae followed Compagno (1973), and was subsequently assigned to a new subgenus Golluminae ( Compagno, 1988). However, in more recent studies ( Compagno 1999; Compagno et al., 2005a, 2005b) it has been relocated to the related carcharhiniform family Pseudotriakidae . Gollum differs from the three proscylliid genera (i.e. Eridacnis Smith , Proscyllium Hilgendorf and Ctenacis Compagno ) in having a deep notch on the lateral margin of the snout forward of the nostrils giving the head a bell-shaped appearance (rather more evenly rounded) when viewed dorsolaterally, and lacking gill rakers and oral papillae ( Compagno, 1988). It shares the family Pseudotriakidae with the monotypic genus Pseudotriakis Capello , which differs from Gollum in having a soft stocky body (firmer and more slender), a very long, keel-like first dorsal fin (relatively taller and much shorter based), and a much shorter caudal peduncle.