Author: Guitart Manday, 1966
Slender, spindle-shaped body, moderately long conical snout, large bladelike teeth without lateral cusplets or serrations, long gill slits, pectoral fins broad-tipped and as long or longer than head, large first dorsal fin with light free rear tip, minute, pivoting second dorsal and anal fins, strong keels on caudal peduncle, short secondary keels on caudal base, crescentic caudal fin, ventral surface of body dusky on underside of head.
Body slender. Snout more bluntiy conical eyes relatively large; cusps of first upper anterior teeth with complete cutting edges; tips of anterior teeth not reflexed, cusps broader and less oblique. Pectoral fins very long and broad tipped, longer than head. Colour: underside of snout at least partly dusky.
Oceanic and tropical. Western North Atlantic: Florida, Gulf Stream off eastern USA, Cuba. Eastern North Atlantic: Guinea, Ghana, ? Cape Verde Islands. Western Indian Ocean: Madagascar. Central Pacific: Near Phoenix Island and north of Hawaiian Islands.
Habitat and Biology:
A little-known epipelagic, tropical and warm-temperate shark, apparently not uncommon in the western Atlantic and possibly in the central Pacific, but rather rare elsewhere. Its often slimmer build and broad, long pectoral fins suggests that it is slower and less active than its better-known relative, the shortfin mako (J. Casey, pers.comm.).
The longfin mako is ovoviviparous, with uterine cannibalism; fetuses are larger than those of I. oxyrinchus, are full-term at 92 to 97 cm, and occur as a litter of two young.
Food of this shark is presumably schooling fishes and pelagic cephalopods. This species has not been implicated in attacks on people or boats but is regarded as potentially dangerous because of its large size and big teeth .
Maximum total length reported 417 cm, an adult male (central Pacific) was adult at 245 cm, adult females (western North Atlantic) were from 245 to 417 cm long; size at birth presumably about 97 cm.
Interest to Fisheries:
Probably taken regularly in the tropical pelagic Japanese longline fisheries (marketed in Tokyo), but otherwise often taken in the Cuban longline fishery off the north coast of Cuba. It is utilized fresh, frozen and dried salted for human consumption. In addition to longlines, the species is taken with hook-and-line, and with anchored gillnets.
Some writers (Garrick, 1967, Compagno and Vergara(1978), Compagno(1981a) thought that the species Lamiostoma belyaevi Glikman, 1964 might prove to be an earlier name for L. paucus, particularly because a stuffed Isurus illustrated in a photograph in Glikman (1964, figs 31-32) and labelled L. belyaevi appeared to be a longfin mako. Unfortunately this may be irrelevant even if correct. A translation of Glikman's description of L. belyaevi (pp 105. 132-133; by Mrs. L.J. Dempster with the aid of Dr V.V. Barsukov) revealed that Glikman deliberately refrained from naming the stuffed Isurus as holotype of L. belyaevi but instead picked one lot of teeth crowns dredged from the ocean bottom 5120 m deep at RV Vitiaz station 5128, 13°00'N, 176°04'E (Glikman, 1964, pl. 31, figs 13, 14, 18, 19) for this role. Examination of Glikman's photos did not convince me that the shark or sharks represented by these teeth were necessarily conspecific with L. paucus and were not conspecific with L. oxyrinchus or even some extinct Isurus species. Hence I cannot recommend the substitution of the species name belyaevi for paucus, especially because the former is based on such poor material. It is uncertain if the stuffed specimen illustrated by Glikman is L. paucus also, because some of the characters ascribed to it (snout very long and acute, pectoral fins falcate, and pectoral fin length slightly less than the distance from snout tip to upper margin of first gill opening, vs. snout short and bluntly conical, pectoral fins not strongly falcate, and pectoral fin length much longer than the distance from snout tip to upper margin of first gill opening in L. paucus) indicate that it might be a specimen of L. oxyrinchus instead.
Holotype: Apparently not named? Type Locality: Probably from Caribbean Sea near Cuba.