click for previous page - 212 - 8. ORDER LAMNIFORMES - MACKERAL SHARKS Order Lamniformes Compagno, 1973c, J.Linn.Soc.(Zool.), 53 Suppl. 1:37 p. Synonymy : Order Asterospondyli: Gill, 1893 (in part); Fowler, 1941 (in part); Smith, 1949 (in part). Order Asterospondyli, Suborder Galei: Jordan & Evermann, 1896 (in part). Superorder Carcharhini, Order Squatinidae, Suborder Squaloidei: Glikman, 1967 (in part, for Cetorhinidae). Order Carcharhiniformes: Ross & Lindberg, 1971 (in part, for Cetorhinidae). Suborder Carchariina: Fowler, 1967 (in part). "Group" Carcharoidei: Garman, 1913 (in part). Order Euselachii, Suborder Galeoidei: Blot, 1969 (in part). Order Galea, Suborder Isurida: White, 1936, 1937 (in part). Suborder Galei: Gill, 1872 (in part), Jordan, 1923 (in part). Order Galeiformes, Suborder Isuroidea: Arambourg & Bertin, 1958 (in part). Suborder Galeiformes: Lozano y Rey, 1928 (in part); Budker & Whitehead, 1971 (in part). Suborder Galeoidea: Romer, 1945, 1966 (in part), Bigelow & Schroeder, 1948 (in part); Norman, 1966 (in part). "Division" Galeoidei: Regan, 1906 (in part). Suborder Galeoidei: Engelhardt, 1913 (in part). Order Isuriformes: Chu & Wen, 1979. "Group" Isuroidei: Garman, 1913 (in part). Suborder Lamnae, Order Odontaspida: Glikman, 1967 (in part, except for Cetorhinidae). Order Lamniformes: Ross & Lindberg, 1971 (in part, except for Cetorhinidae), Applegate, 1974. Order Lamniformes, Suborder Lamnoidei: Berg, 1940 (in part); Berg & Svedovidov, 1955 (in part), Patterson, 1967 (in part). Suborder Lamniformes: Bertin, 1939 (in part). Suborder Lamnina: Matsubara, 1955 (in part). Order Lamncidea, suborder Galeoidea: Schultz & Stern, 1948 (in part). Suborder Lamnoidei: Lindberg, 1971 (in part); Nelson, 1976 (in part). Suborder Scylloidei: Goodrich, 1909 (in part). Suborder Squali: Gill, 1862 (in part). Diagnostic Features : Trunk cylindrical and not raylike. Head conical to cylindrical and not laterally expanded; 5 pairs of gill slits present on sides of head, either entirely in front of pectoral bases or with the last two above the pectoral bases; spiracles usually present and very small, well behind the eyes; nostrils without barbels, circumnarial grooves, or nasoral grooves, well separated from eyes, with anterior nasal flaps not expanded and far from mouth; eyes lateral or slightly dorsolateral on head, without nictitating lower eyelids; snout very short and bluntly rounded to long and conical or flattened, usually not bladelike and not formed as a rostral saw with lateral teeth and vertral barbels; mouth moderately large to very large, strongly arched, extending well behind eyes; labial furrows short or absent, when present on lower jaw; teeth usually well differentiated along jaws, with enlarged anterior teeth, a gap or small intermediate teeth separating the anterior teeth from the lateral teeth in the upper jaw, but with posterior teeth not enlarged. Two dorsal fins, without spines, the first with its origin over the interspace between pectoral and pelvic bases or over the pectoral bases; pectoral fins moderate-sized to large but not raylike, without triangular anterior lobes; pelvic fins small to moderately large, with vent continuous with their inner margins; anal fin present; caudal fin with a long dorsal lobe but with ventral lobe varying from long (but shorter than the dorsal lobe) to absent; vertebral axis raised into the dorsal caudal lobe. Intestinal valve of ring type. Key to Families 1a. Snout greatly elongated and flattened, forming a dagger-like blade. No pre- caudal pits Ventral caudal lobe absent Anal fin broadly rounded (Fig. 1) - Goblin sharks ............................... Family Mitsukurinidae Mitsukurina Fig.1 1b. Snout very short to moderately elon- gated, conical to flattened and broadly rounded but not bladelike. Precaudal pits and ventral caudal lobe present. Anal fin angular 2a. Snout very short and broadly rounded in dorscventral view. Mouth greatly enlarged, terminal on head. Teeth very small, numerous, over 50 rows in each jaw half, and not differentiated into anteriors, laterals, and symphy- seals; no intermediates or inter- Megachasma Fig.2 mediate gap in upper jaw. Internal gill openings with papillose gillrakers (Fig. 2) - Megamouth sharks ..................... Family Megachasmidae - 213 - 2b. Snout longer and narrowly to broadly parabolic in dorsoventral view. Mouth small to moderately large, subterminal on head. Teeth larger, less nume- rous, and less than 50 rows in each jaw half, and differentiated into anteriors, laterals and often symphyseals (symphyseals absent in some species); upper jaw with intermediate teeth or an interme- diate gap between anterior and lateral teeth. Inter- nal gill openings without rakers 3a. Caudal fin about as long as rest of shark. Last two gill openings above pectoral fin base (Fig. 3) -Thresher sharks ................................... Family Alopidae Alopias Fig.3 3b. Caudal fin much shorter than rest of shark. All gill openings in front of pectoral fin base 4a. Caudal fin asymmetrical, not lunate, ventral caudal lobe short, preventral caudal margin much shorter than dorsal caudal margin. Caudal peduncle without lateral keels or with weak ones 5a. Eyes relatively small, body stout. Anal fin broad-based, not pivoting. Caudal peduncle with an upper pre- caudal pit but without a lower pit or lateral keels. Gill openings not Eugomphodus Fig.4 extending onto dorsal surface of head (Fig. 4) - Sand tiger sharks ................. Family Odontaspididae 5b. Eyes very large, body slender. Anal fin narrow-based, pivoting. Caudal peduncle with both upper and lower precaudal pits and low lateral keels on each side. Gill openings extending onto dorsal sur- face of head (Fig. 5) - Crocodile Pseudocarcharias Fig.5 sharks ......... Family Pseudocarchariidae 4b. Caudal fin nearly symmetrical and lunate, with a long ventral lobe and preventral caudal margin nearly as long as dorsal caudal margin. Caudal peduncle with very strong lateral keels 6a. Teeth relatively few, enlarged and bladelike, with less than 40 rows in each jaw. Gill openings large but not extending onto dorsal surface of head; internal gill openings Isurus Fig.6 without gillrakers (Fig. 6) - Mackerel sharks .......... Family Lamnidae 6b. Teeth numerous, minute, hooked and not bladelike, with over 150 rows in each jaw. Gill openings extremely large, extending onto dorsal surface of head; internal gill openings with prominent gillrakers formed from modified dermal den- ticles (Fig. 7) - Basking sharks ..................... Family Cetorhinidae Cetorhinus Fig.7 - 214 - 8.1 FAMILY ODONTASPIDIDAE Müller & Henle, 1839 ODONT Family Odontaspides Müller & Henle, 1839, Syst.Beschr.Plagiost., pt. 2:73.. Family Odontaspididae (correction of Odontaspides) placed on the Official List of Family-Group Names in Zoology (Name no. 3B5) and Odontaspides placed on the Official Index of Rejected and Invalid Family-Group Names in Zoology (Name no. 414) by the International Commission on Zoological Nomenclature, Opinion 723 (1965). Synonymy : Subfamily Triglochidini Bonaparte, 1838 (Family Squalidae). FAO Names : En - Sand tiger sharks; Fr - Requins de sable; Sp - Solrayos, Toros. Field Marks : Large sharks, with conical to slightly depressed, pointed snouts, long mouths extending behind eyes, small eyes without nictitating eyelids, moderately long gill openings, large teeth with slender cusps and lateral cusplets, small intermediate teeth separating anterior and lateral teeth in the upper jaw, two large dorsal fins and an anal fin, small pectoral fins, a compressed caudal peduncle without keels but with an upper precaudal pit, and an asymmetrical caudal fin with a strong but short ventral lobe. Diagnostic Features : Trunk compressed-cylindrical and moderately stout. Head short, much shorter than trunk, snout short to moderately long, pointed and conical to slightly depressed, not greatly elongated, flattened and bladelike; eyes small to moderately large; mouth large, ventral on head; gill openings moderately large, not extending onto dorsal surface of head, all anterior to pectoral fin bases; no gillrakers on internal gill slits; teeth large, anteriors narrow and awl-like but laterals moderately compressed and bladelike, less than 60 rows in either jaw; two or three rows of large anterior teeth on each side of upper jaw, three in lower, the uppers separated from the upper lateral teeth by one of five rows of small intermediate teeth or a gap. First dorsal fin large, moderately high, erect and angular; second dorsal and anal fins about as large as first dorsal or somewhat smaller, with broad, nonpivoting bases, pectoral fins moderately long and broad, much shorter than head in adults; pelvic fins large, nearly or quite as large as first dorsal fin; caudal fin not lunate, upper lobe moderately long, less than half as long as rest of shark, lower lobe short but strong. Upper precaudal pit present, caudal peduncle compressed and without keels. Habitat, Distribution and Biology : Odontaspids are tropical to cool-temperate, inshore and deepwater sharks with a wide geographic distribution in virtually all seas, in continental and insular waters from the surf zone to the outer shelves and down the slopes to possibly 1600 m. All the known species are of large size (to at least 360 cm). These sharks are relatively slow but active littoral and epibenthic swimmers. They feed on a wide variety of bony fishes, other sharks, rays, squids and bottom crustaceans. Development is ovoviviparous, without a yolk-sac placenta but with