Mosasaur Pronunciation Guide
© Ben Creisler
(Moved to Oceans of Kansas, July 5, 2012)
Amphekepubis Mehl 1929 "forked pubis"*
am-FEE-kee-PYOO-bis (Gr. amphekes
"double-pointed" + Lat. pubis "pubis") (m)
named for its distinctive "forked pubis," formed by the development of
a long, slender pubic process projecting from the front of the pubic bone; known
from a pelvic arch, part of a hindlimb and 9 postsacral (pygal and tail)
vertebrae (Holotype: Univ. of Missouri 509VP). The type material was found in
Type Species: Amphekepubis johnsoni [JON-suh-nie] Mehl
1930: for Carlyle D. Johnson, who collected the specimen about 40 miles east of
Amphorosteus Gibbes 1851 "amphora-boned one"
am-fo-ROS-tee-uhs (Gr. amphora, a jar with a narrow neck + Gr. osteon "bone" + -us) (m) named "from the resemblance of the vertebrae, in outline, to an ancient amphora." Late Cretaceous NA. [nomen dubium]
Angolasaurus Telles-Antunes 1964 "
Ancylocentrum Schmidt 1927 "fused centrum"
AN-sil-o-SEN-truhm (Gr. agkylos "crooked, curved" [used in the applied sense "stiff, fused"] + Lat. centrum, central element of a vertrebra) (n) alluding to chevrons fused to the centrum of the tail vertebra. (To replace preoccupied Brachysaurus.) [= Prognathodon]
Baptosaurus Marsh 1870 "diving lizard"
BAP-to-SAWR-uhs (Gr. bapto "plunge" + Gr. sauros "lizard")* (m) to replace Halisaurus Marsh, supposedly preoccupied by Halosaurus Johnson 1864. Because of a one letter difference, Halisaurus is not preoccupied according to current ICZN rules. [= Halisaurus]
Baseodon Leidy 1865 "pedestal tooth"
ba-SEE-o-don (Gr. baseos (basis) "step, pedestal, base" + Gr. odon "tooth") (m) named for the enlarged base of two pterygoid teeth probably belonging to a species of Mosasaurus. Late Cretaceous NA. [nomen dubium]
Batrachiosaurus Harlan 1839 "frog-like lizard"
BAT-tra-KIE-o-SAWR-uhs (Gr. batrakheios "frog-like" + Gr. sauros "lizard") (m) named to indicate an animal that supposedly "approaches" the "batrachian reptiles" in the "form and position of the intermaxillary bones"; proposed for Mosasaurus ("Ichthyosaurus") missouriensis. [= Mosasaurus]
Brachysaurana Strand 1928 "short lizard"
BRAK-ee-saw-RAY-nuh (Gr. brachys + Gr. saura "lizard" + -ana) (f) to replace preoccupied Brachysaurus--Ancylocentrum has priority as a replacement name. [= Prognathodon]
Brachysaurus Williston 1897 "short lizard"
BRAK-ee-SAWR-uhs (Gr. brakhys "short" + Gr. sauros "lizard") (m) named for the broad and large frontal bones of the skull. (Preoccupied by Brachysaurus Hallowell 1856. See Ancylocentrum.) [= Prognathodon]
Carinodens Thurmond 1969 "keeled tooth"
kah-RIEN-o-denz (Lat. carina "keel" + Lat. dens
"tooth")* (m) referring to the carina (raised cutting edge) along the
teeth; new name to replace preoccupied Compressidens Dollo 1924 (proposed
for "Globidens" fraasi Dollo 1913). The genus is known
from a small, toothed dentary (183 mm long) (IRSNB 6571) and several isolated
teeth. The teeth are broad, pointed, and laterally compressed, with carinae on
the front and back edges; teeth in the front of the jaw are narrower and
subcircular in cross-section. The robust blunt shape of the teeth indicates they
were probably used to crush crustaceans or invertebrates with thin shells such
as Nautilus--the teeth and jaws were likely too delicate to crush the
more heavy-shelled mollusks preyed on by Globidens. The coarse rib- or
fan-like wrinkles on the surface of the teeth are more developed than in Globidens,
and would have strengthened the tooth and concentrated stress in the food item
(Lingham-Soliar 1999). According to Kuypers, Jagt, Peeters and De Graaf (1998),
and Lingham-Soliar (1999), the distinction between Carinodens fraasi and C.
belgicus is based only on differential wear on the functioning teeth:
"The tricuspid pattern on some teeth [in C. belgicus] constituted
simple wear on the rounded anterior and posterior edges and on the central cusp
of the more rectangular-shaped teeth. The condition presumably occurred in older
teeth nearing replacement." (Lingham-Soliar 1999). Kuypers, Jagt, Peeters
and De Graaf (1998) made Carinodens fraasi a junior synonym of C.
belgicus. Additional material has been identified from the
Type Species: Carinodens belgicus [BEL-ji-kuhs] (Woodward 1891)
"Belgian": originally identified as "Bottosaurus" belgicus
Woodward 1891, a supposed Belgian species of the Late Cretaceous North American
alligator Bottosaurus Agassiz ("(Paul-Emile) Botta's reptile"),
based on teeth found in the Craie de Ciply of
Clidastes Cope 1868 "(vertebrae) locker"
klie-DAS-teez (from Gr. kleidoo "to lock up" + Gr. suffix -astes "one who performs an action"; by analogy with Gr. dynastes "ruler," kolastes "punisher," etc.) (m) Cope originally proposed the name Clidastes (literally "one who locks") for a single, isolated vertebra from the Marshalltown Formation of New Jersey, with the type species Clidastes iguanavus "iguana ancestor," for its supposed similarity to the vertebrae of modern iguanas. The vertebra was notable for a zygosphene and a zygantrum--extra bony articulations that help "lock" vertebrae one to the other in the flexible backbones of lizards and snakes, and thus serve to restrict vertical bending. Cope described mosasaurs as having "the arches of the vertebral column interlocked more extensively than in other reptiles except the snakes," adding with a burst of imagination that in "Clidastes, this structure is as fully developed as in the serpents, so that we can picture to ourselves its well known consequences: their rapid progress through water by lateral undulations; their lithe motions on land; the rapid stroke; the ready coil; or the elevation of the head and vertebral column, literally a living pillar towering above waves or brush of the shore swamps." (Cope 1869). However, Clidastes' vertebrae differed "from the dorsals of known serpents in having a zygosphen on the plane of the anterior zygopophysis." (See additional comments at "Pythonomorpha.") The discovery of more complete fossils debunked Cope's vision of Clidastes and other mosasaurs as huge, coiling snakelike animals, and showed that not all mosasaurs had interlocking zygosphenes and zygantra on their vertebrae.
Clidastes was relatively small (only up to 6 m. (20 ft.)long) mosasaur with a thin elongated body and a relatively short flattened tail. The expanded neural spines toward the tip of the tail aided propulsion and suggest Clidastes was a fast swimmer-- there is no preserved fossil evidence for an additional sea- snake-like soft-tissue fin to further enlarge the end of tail as depicted in some restorations, however. In other ways, Clidastes represents a relatively primitive (less derived) type of mosasaurine, particularly in its limb structure (small number of phalanges on digits, digits widely spaced, carpus retaining primitive elements; but shapes of humerus, radius and ulna highly modified as short and broad) and in its somewhat kinetic skull (though the bones allow less intercranial movement than in most plioplatecarpines). The skull also has a distinctive short, pointed rostrum projecting beyond the front teeth, producing a v- shaped dorsal profile. The teeth are compressed and bicarinate with smooth enamel surfaces. Russell (1967) suggested that: "The long slender jaws of Clidastes were probably adapted to rapid biting." The slicing teeth "might have been effective in sawing a large object into pieces of swallowable size" when the lower jaw was moved backward and forward. Thus, unlike many other mosasaurs that probably swallowed most prey whole, the relatively small Clidastes may have been able to reduce a victim to bite-sized chunks.
Its lifestyle is still debated. Williston (1898) intrepreted Clidastes as an apparent surface feeder. Martin and Rothschild (1989) concurred, noting that Clidastes' bones do not show evidence of "the bends" or decompression syndrome (avascular necrosis), indicating to them that it "lived near shore" and "did not regularly engage in deep diving." However, Sheldon (1997) analyzed the microstructure of ribs from Clidastes and discovered low bone density (osteoporosis)--the porous bones would have been filled with lipids, providing neutral bouyancy over a greater range of depths. Based on comparisons with living marine vertebrates, Sheldon concluded that Clidastes was in fact built to be a deep diver--its "thorax construction was conducive to lung compression," which would have decreased diffusion of gases into the bloodstream and thus would have prevented the avascular necrosis found in the bones of mosasaurs such as Platecarpus that were adapted to live in shallower depths.
The single type specimen vertebra (Clidastes iguanavus) that inspired the generic name is no longer considered diagnostic and probably belongs to Mosasaurus; the generic name Clidastes was conserved with a new type species (Clidastes propython) and new holotype specimen (ANSP 10193) by ICZN Opinion # 1750 (1993), based on a nearly complete skeleton and skull from the Selma Formation of Alabama that Cope had identified as Clidastes from the presence of a zygosphene and a zygantrum on the dorsal vertebrae.
Vertebrae: 42 presacrals / 7 pygals/ 26 intermediate caudals with
chevrons and transverse processes / 46 terminal caudals
Length: up to 6.2 m. (21 ft.); skull: 65.8 cm (2.2 ft.)
Type Species: Clidastes propython [proh-PIE-thon] Cope 1869 "before-python": referring to what Cope saw as "ophidian affinities" in mosasaurs, especially in the vertebrae and certain parts of the skull--he classified mosasaurs in a separate order of reptiles called the Pythonomorpha "python forms" (see Pythonomorpha). Based on a nearly complete skeleton and skull (Holotype: ANSP 10193) found in the Selma Formation (Rotten Limestone), near Uniontown, Alabama; made the type species in place of Clidastes iguanavus ("iguana ancestor") by ICZN Opinion 1750 (1993).
Additional Species: Clidastes liodontus [lie-o-DON-tuhs] Merriam 1894 "smooth-toothed": "All the teeth on the maxillary, premaxillary and dentary bones are completely smooth and can be compared with those of Liodon Owen, from which they are almost, if not totally, indistinguishable." (Merriam 1894); originally based on maxillae, premaxilla and dentaries--now known from a number of nearly complete skeletons.
NOTE: "Clidastes moorevillensis," from the Mooreville
Compressidens Dollo 1924 "compressed tooth"
com-PRES-i-denz (Lat. compressus "compressed" (from comprimo "press together) + Lat. dens "tooth") (m) named for the laterally compressed shape of teeth, unlike the rounded teeth of Globidens (preoccupied by Compressidens Pilsbury & Sharp 1897. See Carinodens) [= Carinodens]
Dollosaurus Yakovlev 1901
DOL-o-SAWR-uhs (Dollo + Gr. sauros "lizard")
(m) named to honor Louis Dollo (1857-1931), noted Belgian paleontologist who
studied mosasaurs; known from a partial skull and skeleton from the
Type Species: Dollosaurus lutugini [loo-TOO-gee-nie]
Yakovlev 1901: for Leonid Ivanovich Lutugin (1864-1915), Russian geologist and
cartographer, who studied the
Drepanodon Leidy 1856 "sickle tooth"
dre-PAN-o-don (Gr. drepane "sickle, scythe" + Gr. odon "tooth") (m) for the sharp blade-like shape of the tooth. Late Cretaceous NA. [nomen dubium]
Ectenosaurus Russell 1967 "drawn-out (snout) lizard"
EK-ten-o-SAWR-uhs (Gr. ektenes "drawn-out" +
Gr. sauros "lizard")* (m) referring to the thin,
elongated form of the muzzle; for "Platecarpus" clidastoides
Merriam 1894. Ectenosaurus is closely related to Platecarpus, with
a similar, highly kinetic skull, but differs in the narrow, elongated shape of
its snout, and in certain features of the skull bones and of the forelimbs. The
original type material at the Bayerische Staatssammlung fuer Palaeontologie in
Length: (estimated) 6 m. (20 ft.); skull: .65 m. (2.2 ft.)
Type Species: Ectenosaurus clidastoides [klie-das-TOY-deez] (Merriam 1894) "Clidastes-like"; for a resemblance to Clidastes in the shape of the back of the skull. Plioplatecarpinae Late Cretaceous (Santonian-Campanian) NA.
Edestosaurus Marsh 1871 "devourer lizard"
e-DES-to-SAWR-uhs (Gr. edestes "devourer" + Gr. sauros "lizard")* (m) named for its carnivorous nature. [= Clidastes]
Elliptonodon Emmons 1858 "elliptical tooth"
e-lip-TON-o-don (from Gr. elleiptikos "elliptical" +
Gr. odon "tooth") (m) based on a single tooth from
Globidens Gilmore 1912 "globular tooth"
GLOB-i-denz (Lat. globus "globe, sphere" + Lat. dens
"tooth") (m) named for the rounded globular shape of its teeth,
designed for crushing hard-shelled mollusks (more likely ammonites rather than
clams or gastropods) and possibly the shells of turtles. Globidens is a
fairly small, specialized mosasaur with a short, massive head, and jaws
containing bulbous to blunt-tipped teeth with strongly constricted bases and a
covering of wrinkles; pterygoid teeth on the palate are absent or very
rudimentary (unlike in other mosasaurs, which have functional pterygoid teeth).
The vertebrae have weakly developed zygapophyses. The skull and vertebrae show a
close relationship to Clidastes (Russell 1975). New North American
material (not yet described) includes a nearly complete skeleton.
Similar-looking tooth material from Africa, Europe, Middle East and
Length: (estimated) 5.5-6 m. (18-20 ft.); skull: (estimated) .47 m. (19 in.))
Type Species: Globidens alabamaensis
[AL-uh-bam-uh-EN-sis] Gilmore 1912 "from
Globidens dakotensis [dak-o-TEN-sis] Russell 1975 "from
(South) Dakota": found in the Sharon Springs Member of Pierre Shale, in
Goronyosaurus Azzaroli, de Guili, Ficcarelli & Torre 1972
goh-RON-yo-SAWR-uhs (Goronyo + Gr. sauros
"lizard") (m) named for the Goronyo district of
Length: (estimated) 7 m. (24 ft.); skull: (estimated) .62 m. (2 ft.); lower jaw: (estimated) .7 m. (2.3 ft.).
Type Species: Goronyosaurus nigeriensis [nie-jeer-ee-EN-sis] (Swinton
Hainosaurus Dollo 1885 "Haine (River) lizard"
EN-o-SAWR-uhs (Haine + Gr. sauros "lizard")
(m) named for the
Vertebrae: 40 presacrals / 9+ pygals / 30-35 intermediate caudals /
Length: (estimated) 12-15+ m. (40-50+ ft.); skull: 1.5+ m. (5+ ft.)).
Type Species: Hainosaurus bernardi [ber-NAR-die] Dollo
1885: for Leopold Bernard, a Belgian industrialist who permitted the excavation
of the holotype fossils on his phosphate mining concession at
Additional Species: Hainosaurus pembinensis [pem-bi-NEN-sis]
Nicholls 1988 "from Pembina": for the Pembina Member of the Pierre
Shale (early Campanian), Mantiboa,
Hainosaurus gaudryi [goh-DREE-ie] (Thevennin 1896): for Jean
Albert Gaudry (1827-1908), French paleontologist; originally as "Mosasaurus"
gaudryi Thevennin 1896--the teeth are typically tylosaurine with a deep
cross-section and striations on the buccal and lingual sides. (Santonian of
Halisaurus Marsh 1869 "sea lizard"
HAL-i-SAWR-uhs (Gr. halis (hals) "sea" + Gr. sauros "lizard")* (m) named to indicate a marine reptile. Marsh later assumed the name was preoccupied by Halosaurus Johnson 1864 (a fish) and provided the unnecessary replacement name Baptosaurus for his Halisaurus. (A one-letter spelling difference is adequate to distinguish two generic names under modern rules of nomenclature.)
Halisaurus remains a problematic taxon. It appears to have been a
small mosasaur with primitive-looking vertebrae and a highly kinetic skull.
Fragmentary fossils identified as Halisaurus indicate a wide geographic
range (North America, South America, Europe, Africa) and a surprisingly long
stratigraphic occurrence (ten million years from
Marsh's type species Halisaurus platyspondylus is based on an
angular bone, braincase fragments, and two vertebrae (cervical and dorsal) that
lack a zygosphen and a zygantrum (Holotype: YPM 444), found in the New Egypt
Formation (Maastrichtian) in New Jersey: Merriam added the species Halisaurus
onchognathus (as Baptosaurus onchognathus) in 1894, based
on a partial skull and lower jaw, associated with Halisaurus-like
vertebrae found in the Niobrara (Santonian-Campanian) of Kansas and sent to a
German collection (destroyed in WWII). Russell (1967) accepted the two species
in the same genus, even though they are widely separated in time. Baird and Case
(1966) identified a frontal bone from
Length: (estimated based on H. ortliebi): up to 4.5 m. (15 ft.); skull: 40 cm (16 in).
Type Species: Halisaurus platyspondylus [plat-ee-SPON-di-luhs] Marsh 1869 "broad vertebrae": for the broadened, compressed shape of the vertebrae.
Halisaurus onchognathus [ong-KOG-na-thuhs] (Merriam 1894)
"hook- jaw": "the hind end of the lower jaw has a hook-like
appearance"; type specimen in the
Halisaurus ortliebi [ort-LEE-bie] (Dollo 1889); for Jean Ortlieb, Belgian geologist and director of the research laboratory of the Society Solvay and Cie; originally described as Phosphorosaurus ortliebi Dollo 1889. The species is only known from a fragmentary skull (IRSNB R34); Lingham-Soliar (1996) identified it as a form of Halisaurus based on the narrow frontal bone in the skull, even though no associated vertebrae (the usual diagnostic feature of Halisaurus) are currently known.
Halisaurus ("Clidastes") sternbergii [stuhrn-BUHR-gee-ie]
(Wiman 1920): for Levi Sternberg (1894-1976), who discovered the type specimen
Holcodus Gibbes 1851 "striated tooth"
HOL-ko-duhs (Gr. holkos "furrow, track" + Gr. odous "tooth") (m) named for "teeth...peculiarly striated toward the base." Late Cretaceous NA. [nomen dubium]
Holosaurus Marsh 1880 "complete lizard"
HOL-o-SAWR-uhs (Gr. holos "entire" + Gr. sauros "lizard")* (m) named for the completeness of the type specimen: "based on one of the most complete skeletons of the Mosasauroid reptiles yet discovered." [= Platecarpus]
Igdamanosaurus Lingham-Soliar 1991 "Igdaman (
EEG-dah-MAHN-o-SAWR-uhs (Igdaman + Gr. sauros "lizard") (m) named for the village of Igdaman, near where the type specimen material was found in Niger, west Africa; known from a fragmentary jaw (Holotype: BMNH R11898) and isolated teeth. Igdamanosaurus was apparently a shell-crushing form that evolved in the plioplatecarpine line of mosasaurs, independently of the mosasaurine Globidens. Notable for a massive dentary (lower jaw) with broad domed teeth but marked by fine striations and unconstricted at the base, unlike the teeth of Globidens. Igdamanosaurus fits the tooth morphotype of Massare's "crunch" guild and probably fed on moderately soft-shelled invertebrates (cephalopods), in constrast to Globidens (a member of the "crush" guild with very broad bulbous teeth to process hard-shelled invertebrates and turtles). Igdamanosaurus is a small mosasaur, probably around 3.6 m (12 ft.) long.
Type Species: Igdamanosaurus aegyptiacus [ee-jip-TIE-a-kuhs] (Zdansky
1935) "Egyptian": after teeth found in
Kolposaurus Camp 1942 "bay lizard"
KOL-po-SAWR-uhs (Gr. kolpos "bay, estruary, gulf" + Gr. sauros "lizard")* (m) named to indicate a form that may have frequented the near-shore. (Preoccupied by Kolposaurus Skuphos 1893. See Plotosaurus) [= Plotosaurus]
Leiodon Owen 1841 "smooth tooth"
LIE-o-don (Gr. leios "smooth" + Gr. odon "tooth")* (m) named "in reference to the smooth and polished surface of the teeth." Owen's original spelling Leiodon is preoccupied by Leiodon Swainson 1839 (Pisces: Tetraodontidae) (See Hay (1903), Bibliography of North American Fossil Vertebrates and Eschmeyer (1990), The Genera of Recent Fishes) and therefore is NOT valid as a generic name, contrary to Lingham-Soliar 1993 ("The Mosasaur Leiodon Bares its Teeth" Modern Geology 1993 18: 443-458.) See Liodon. [= Liodon]
Liodon Agassiz 1846 "smooth tooth"
LIE-o-don (Gr. leios "smooth" + Gr. odon
"tooth")* (m) named "in reference to the smooth and polished
surface of the teeth" (Owen 1840); valid name for Leiodon Owen 1841
(preoccupied by Leiodon Swainson 1839); based on a jaw fragment with
large blade-like, somewhat recurved teeth having smooth enamel (Holotype: BMNH
41639), found in Essex, England. The genus has a confused taxonomic history, but
Lingham-Soliar ("The Mosasaur Leiodon Bares its Teeth" Modern
Geology 1993 18: 443-458) has argued that the genus is distinct and definable. Liodon
was a large mosasaur with "powerful, highly specialised teeth...probably
the most efficient in the Mosasauridae for tearing off chunks of soft bodied
prey such as fishes and other marine reptiles...[Liodon] was a formidable
predator, the nearest mosasaur analogue to sharks." (Lingham-Soliar 1993).
The postcranial skeleton has not been described--Lingham-Soliar (1993) suggests
that a skeleton from
Owen's original spelling Leiodon is preoccupied by the fish name Leiodon
Swainson 1839 (Pisces: Tetraodontidae).
Length: (estimated) up to 12+ m. (40+ ft.)); skull: 1.2 m. (4 ft.)
Type Species: Liodon anceps [AN-seps] (Owen 1840) "two-edged": referring to the carinae or cutting edges (front and back) on the teeth: "the anterior edge is most produced"; known mainly from jaw fragments and isolated teeth.
Liodon mosasauroides [moh-suh-saw-ROY-deez] Gaudry 1892 "Mosasaurus-like"
the largest known species (estimated 12+ m. (40+ ft.), with the most laterally
compressed teeth; found in SW France in the
Liodon sectorius [sek-TOR-ee-uhs] Cope 1871
"cutting": referring to its double-edged teeth; a small species
(estimated around 25- 30 ft. long) known from jaws (including a nearly complete
dentary) from the Navesink Formation,
Lesticodus Leidy 1859 "predatory tooth"
les-TIK-o-duhs (Gr. lestikos "predatory, piratical" + Gr. odous "tooth") (m) based on an isolated pterygoid tooth. Late Creteceous NA. [nomen dubium]
Lestosaurus Marsh 1872 "pirate lizard"
LES-to-SAWR-uhs (Gr. lestes "pirate, robber" + Gr. sauros "lizard")* (m) named to indicate a fierce, predatory marine reptile. [= Platecarpus]
Macrosaurus Owen 1849 "long lizard"
MAK-ro-SAWR-uhs (Gr. makros "long" + Gr. sauros
"lizard") (m) named "from the length of the body indicated by the
proportions of the vertebrae"; based on two vertebrae from
Moanasaurus Wiffen 1980 "sea lizard"
maw-UH-nuh-SAWR-uhs (Maori moana "sea" + Gr. sauros
"lizard")* (m) named to indicate a marine mosasaur found in
Length: (estimated) 12 m. (40 ft.); skull: (estimated) 78 m. (2.5 ft.))
Type Species: Moanasaurus mangahouangae [MUHNG-uh-haw-WUHNG-ee]
(Wiffen 1980) from the Mangahouanga Stream, North Island, New Zealand (Synonyms:
Rikkisaurus tehoensis, Mosasaurus flemingi) NOTE: A second
species may be described based on material from New Zealand previously
attributed to Prognathodon overtoni (Gorden Bell, personal
communication). Mosasaurinae Late Cretaceous (Campanian-Maastrichtian)
Mosasaurinae (Gervais 1853) Williston 1897 "Mosasaurus subfamily"
moh-suh-saw-RIE-nee (Mosasaurus + -inae) (fem. plural) subfamily of the Mosasauridae containing long-bodied mosasaurs with a long trunk section (usually 42-45 presacral vertebrae); zygosphenes and zygantra present on the vertebrae in most taxa; haemal arches on the underside of the tail fused with the centra; enlarged vertebrae form a fin at the end of the tail in some forms (Clidastes, Plotosaurus). Limb structure often highly modified (compact, elongated paddles with extra phalanges; radius and ulna broad and short). Skull is akinetic in more advanced forms (Mosasaurus, Plotosaurus, Globidens). Includes some of the most derived and specialized forms of mosasaurs, as well as the most gigantic (Mosasaurus).
Members: Mosasaurus (type genus); Amphekepubis, Carinodens, Clidastes, Globidens, Liodon, Moanasaurus, Plotosaurus
(NOTE: Bell (1997) includes Prognathodon and Plesiotylosaurus in the Mosasaurinae.)
Mosasaurus Conybeare 1822 "
MOH-suh-SAWR-uhs (Mosa, Latin name for the Meuse River + Gr. sauros "lizard") (m) Latinized version of Cuvier's term "great lizard of the Meuse," after the Meuse River near Maastricht, Netherlands (Holland), where the type skull (Holotype: NMHN AC. 9648) was found in 1780. Mosasaurus was one of the last, most advanced, and largest of all mosasaurs. It had a robustly constructed skull and lower jaw (more tightly united than in other mosasaurs), with relatively immobile bony parts and modified musculature (unlike the kinetic skulls, expandable jaws and lizard-like musculature found in earlier mosasaurs). The powerful backward curving jaw teeth were capable of both crushing and cutting; the pterygoid teeth on the palate were small (reduced in importance in rachet feeding). The parietal foramen for the pineal eye is the smallest of any mosasaur. According to Lingham-Soliar (1995), the moderately large orbits and relatively low level of binocular vision, along with poorly developed olfactory organs, suggest Mosasaurus hoffmanni was a surface- swimming animal adapted to an open, relatively uncomplicated habitat in nearshore waters 40-50 m. in depth. The skeleton had around 46 presacral vertebrae and 80 tail vertebrae, with a deep, barrel-shaped trunk. The compact and elongated ichthyosaur-like limb fins had extra phalanges. Healed injuries to the mandible in a number of specimens indicate a violent lifestyle, likely including fighting with members of its own species. A number of species have been distinguished, some based mainly on differences in tooth shape. Gorden Bell (1997) considers the genus paraphyletic.
Mosasaurus was first large Mesozoic reptile identified. The type
specimen skull in the National Museum of Natural History in
Vertebrae: 45-46 presacrals / 8 pygals / 21 intermediate caudals with
chevrons / 54+ terminal caudals
Length: (estimated) 12.5-17.6 m. (40-59 ft.); skull: 1.5+ m. (5+ ft.) jaw: 1.6+ m. (5.2+ ft.))
Type Species: Mosasaurus hoffmanni [HOF-muh-nie] Mantell 1829: for Dr. C.K. Hoffmann, a retired military surgeon who originally collected the type specimen from the chalk quarry at Saint Peters Mount, Maastricht, Netherlands around 1780; the largest known species, probably reaching close to 18 m. (60 ft.) in length (Lingham-Soliar 1995). The species "shows the most advanced form of tooth facetting in marine reptiles; each crown providing numerous cutting or breaking edges." (Lingham-Soliar 1995).
Mosasaurus conodon [KOH-no-don] (Cope 1881) "cone
tooth": for smoothly surfaced conical teeth; originally based on skull and
jaw parts, 12 vertebrae, scapula, coracoid, humerus and pectoral limb elements
from the Navesink Formation of Monmouth County, New Jersey as "Clidastes"
conodon. Russell (1967) referred a large, nearly complete specimen (with
a badly eroded cranium) from
Mosasaurus dekayi [de-KAY-ie] Bronn 1838: for James Ellsworth De Kay (1792-1851), American zoologist, who first described the type material; originally known from teeth and a few vertebrae from the Navesink Formation of New Jersey. Bell, Martin, Paris & Grandstaff (1994) cite the discovery of a new specimen (partial skull) found along the Missouri River in South Dakota (Late Maastrichtian), identified by its highly distinctive assymetrically bicarinate, extremely prismatic teeth.
Mosasaurus ivoensis [ee-voh-EN-sis] Persson 1963: for Ivo
parish in the Scania region of southern
Mosasaurus lemonnieri [luh-mon-YAYR-ie] Dollo 1889: for Alfred Lemonnier, a Belgian industrialist who presented the type fossil (a nearly complete skull with parts of the atlas/axis vertebrae) to the Royal Museum of Natural History at Brussels; known from a number of skeletons--the number of vertebrae with functional zygosphenes extend further back along the backbone toward the posterior trunk section than is recorded in other species of Mosasaurus (Lingham-Soliar 1991).
Mosasaurus maximus [MAK-si-muhs] Cope 1869:
"largest"--"The remains indicate an animal of the largest size,
perhaps seventy- five feet in length." (Cope 1869); for a very large
species (now estimated at 40.66 ft long) from the Navesink Formation of New
Jersey; additional material has been identified from
Mosasaurus missouriensis [mi-soor-ee-EN-sis] (Harlan 1834)
Mosasaurus mokoroa [maw-kaw-RAW-uh] Gregg & Welles 1971 "long lizard": "From the Maori moko -lizard and roa -long, a name suggested by Dr. Roger Duff, Director of the Canterbury Museum"; for a species from New Zealand (skull: .7 m. long) Mosasaurinae Late Cretaceous (Santonian-Maastrichtian) NA., Eur., Afr., New Zealand, Ant., ?Japan
Nectoportheus Cope 1868 "swimming destroyer"
NEK-to-POR-thee-uhs (Gr. nekto "swim" + Gr. portheus
"destroyer") (m) for a single large vertebra from
Oterognathus Dollo 1889 "different jaw"
o-te-ROG-na-thuhs (for Gr. hoteros "the other" + Gr. gnathos "jaw" + -us) (m) According to Dollo, "its mandible, absolutely unique in the suborder Mosasauria...extremely gracile, indicating a weak ability to chew" [= Plioplatecarpus]
Phosphorosaurus Dollo 1889 "phosphate lizard"
FOS-for-o-SAWR-uhs (Gr. phosphoros "light-giving" +
Gr. sauros "lizard") (m) named for the phosphated brown chalk
at Hainaut, near
Platecarpus Cope 1869 "oar wrist"
PLAT-ee-KAHR-puhs (Gr. plate "oar" + Gr. karpos "wrist, carpus")* (m) named for the flattened paddle-like construction of the limb bones in mosasaurs: "The anterior limbs are fins, with all the elements in a single plane, the radius incapable of rotation. The humerus broad and flat." (Cope 1869) (The name is sometimes misspelled "Platycarpus" ("flat wrist")--Cope gave the etymology as Greek plate "an oar.") Platecarpus was a medium-sized mosasaur with a highly kinetic skull and unspecialized post-cranial anatomy. The body is relatively short and stout, while the tail is fairly elongated. Teeth are long, slender and circular in cross-section. Documented stomach contents include remains of small fish. Preserved scales//////
Platecarpus now appears to have been adapted to life in shallow water as an ambush predator, although this proposed ecological niche contradicts some earlier speculation. Williston (1898) thought Platecarpus might have been a deep diver, based on its ossified external ear (a feature found in many types of mosasaurs), its relatively short and thick body, and its almost smooth scales, making the animal slick and free of drag. Martin and Rothschild (1989) found evidence of decompression syndrome (avascular necrosis) in a high percentage of Platecarpus bones sampled, which seemed to support Williston's idea about deep diving. However, Sheldon (1997) found pachyostosis in the bone microstructure of its ribs and concluded Platecarpus was in fact adapted to life in shallow water much like a modern beluga whale, perhaps lying in ambush on bottom sediments. If it was forced to dive deeply, it could not compress is rigid, thickened rib cage and would have suffered the "bends" (decompression syndrome).
Artists have often depicted mosasaurs incorrectly with an iguana- like nuchal fringe running from the neck along the back to the end of the tail. This error can be traced to a paper by Williston (1899) describing a specimen of Platecarpus--he misidentified preserved tracheal rings from the throat as impressions of a dermal crest along the top of the neck. Williston (1902) later corrected his mistake, but many artists have overlooked his retraction and continue to add the dermal fringe to mosasaurs, often embellishing the crests to fantastic dimensions. There is currently NO preserved soft-tissue evidence for either a dorsal frill or an enlarged fleshy tail-fin on any known mosasaur specimen--mosasaurs appear to have had a sleek, hydrodynamic body outline.
Vertebrae: 29 presacrals / 5 pygals / 26-31 caudals with chevrons and
transverse processes / 65 terminal caudals
Length: 7.5 m. (25 ft.); skull: .7 m. (2.3 ft.))
Type Species: Platecarpus tympaniticus [tim-pa-NIT-i-kuhs]
Cope 1869 "about tympanic bones": alluding to the "marked
differences" in the construction of the quadrate bone compared to Mosasaurus:
"broad as long, meatus larger." Leidy (1865) called the quadrate a
"tympanic bone" (a term now reserved for mammal anatomy) in his
original illustration of the type material found by William Spillman near
Platecarpus coryphaeus [kor-i-FEE-uhs] (Cope 1872)
"leader": alluding to the type specimen: "a fine relic...one that
leads its genus in size and explains its structure" (Cope 1875); originally
called Holcodus coryphaeus Cope 1872. Cope endured considerable misery to
excavate the type specimen from a high bluff in
Platecarpus ictericus [ik-TAYR-i-kuhs] (Cope 1871) "from the yellow (chalk)"; referring to the Niobrara Formation yellow chalk at Smoky Hill River, near Fort Wallace, Kansas; originally classified as Holcodus ictericus Cope 1871. (Holotype: AMNH 1559)
Platecarpus planifrons [PLAN-i-fronz] (Cope 1874) "flat forehead"; originally as Clidastes planifrons Cope 1874: "the frontal bone is especially massive, and is plane on the superior surface."
Platecarpus bocagei [boh-KAH-zhay-ie] (Antunes 1964): named to
honor Jose Vicente Barboza du Bocage (1823-1908), famous Portuguese naturalist
who described the living reptiles of
Plesiotylosaurus Camp 1942 "near-Tylosaurus"
PLEE-see-o-TIE-lo-SAWR-uhs (Gr. plesios "near
to" + Tylosaurus "knob (snout) lizard") (m) named in
reference to its large skull, described as "elongate and narrow,
approaching Tylosaurus in proportions, but without an elongate, conical
rostrum" (Camp 1942). Despite the overall skull shape, Plesiotylosaurus
is not closely related to Tylosaurus, and researchers traditionally
classify the genus in the subfamily Plioplatecarpine close to Prognathodon;
Length: (estimated) 10 m. (33 ft.); skull: .88 m. (35 in.); lower jaw: .98 m. (3 ft.))
Type Species: Plesiotylosaurus crassidens [KRAS-i-denz] Camp 1942 "thick-toothed": for its "large and heavy" mandibular teeth. Plioplatecarpinae (or Mosasaurinae) Late Cretaceous (Maastrichtian) NA.
Plioplatecarpinae (Dollo 1884) Williston 1897 "Plioplatecarpus subfamily"
PLIE-o-plat-ee-kahr-PIE-nee (Platecarpus + -inae) (fem. plural) subfamily of the Mosasauridae containing short-bodied mosasaurs, with relatively short trunk section (29 or fewer presacral vertebrae); skull is kinetic in most forms, with movable bones in both the upper and lower jaws. Skull kinesis is greatly reduced in Prognathodon and Plesiotylosaurus, forms with conical, straight teeth and a crushing bite. The haemal arches not fused to tail vertebrae except in Prognathodon.
Members: Plioplatecarpus (type genus); Ectenosaurus, ?Halisaurus, Igdamanosaurus, Platecarpus, Plesiotylosaurus, Prognathodon, Selmasaurus, Yaguarasaurus
Undescribed Members: The recently announced "Oronosaurus," found in the Negev Desert of Israel (see http://www.discovery.com/news/archive/news990914/brief4.html?ct=37dfec1a), appears to be closely related to Prognathodon, but is larger--probably in the 40 ft. range with a 5-foot-long skull. No formal description has been published yet.
Plioplatecarpus Dollo 1882 "more-Platecarpus"
PLIE-o-plat-ee-KAHR-puhs (Gr. pleion "more" + Platecarpus)
(m) named to indicate that its closest affinities were to Platecarpus,
based on the form of the teeth (recurved, striated), lack of zygosphenes, and
unfused chevrons (free haemal arches) on the tail. The more massive humerus and
compact fore-paddle set it apart. Most species are known from incomplete
material. Recently much better fossils have been found for the North American
species Plioplatecarpus primaevus, including a nearly complete
skeleton from Canada (Holmes 1996) and embryos associated with a skeleton from
South Dakota (Bell, Sheldon, Lamb & Martin 1996), providing evidence that
mosasaurs gave birth to live young. Another even larger species (yet to be
described) is known from a skull and skeleton about 70% complete found in
Plioplatecarpus appears adapted to shallow water, perhaps as a highly
maneuverable ambush predator in seaweed beds or coral reefs (Lingham-Soliar
1994). The highly kinetic jaws and weakly implanted teeth would fit a diet of
soft cephalopods. The teeth are sharp and strongly curved backward, suggesting
it also used rachet feeding (similar to some snakes) when devouring larger
prey--the curved teeth would prevent prey from escaping away from the throat.
The brain appears to have been proportionately twice as large as in Mosasaurus,
perhaps indicating more complex and adaptable behavior; the parietal foramen
containing the pineal eye is also enormous compared to some other mosasaurs.
Lingham- Soliar (1993) has suggested at least one species of Plioplatecarpus
(P. marshii) could use its forelimbs to perform underwater flight similar
to penguins or sealions while maneuvering in its complex marine environment, but
other researchers (Nicholls & Godrey 1994; Holmes, Caldwell & Cumbaa
1999) dispute this interpretation of the animal's limb structure, at least for
other species such as Plioplatecarpus primaevus. Specimens have
recently been identified from
Vertebrae: 7 cervicals / 15 dorsals / 16 pygals / 24 intermediate
caudals / 58 terminal caudals
Length (P. marshii): 6 m. (20 ft.); skull (est.) : 52 cm (21 in.)
Type Species: Plioplatecarpus marshii [MAHR-shee-ie]
Dollo 1882 for O. C. Marsh (1831-1899), noted American paleontologist, who had
visited the Royal Museum in Brussels and was the first to point out that the
specimen (which he attributed to Liodon) differed from the genus Mosasaurus.
Notable for a very slender dentary bone and a compact, well-developed forepaddle.
Lingham- Soliar (1992) has interpreted the limb-structure as evidence of
underwater flight similar to plesiosaurs in this species rather than typical
mosasaur tail-propulsion. (Holotype: IRSNB R38)
Plioplatecarpus houzeaui [hoo-ZOH-ie] (Dollo 1889) : for M. A. Houzeau de Lehaie, member of the Chamber of Representatives and Vice President of the Belgian Society of Geology, Paleontology and Hydrology, who helped secure important fossils for the Royal Museum of Natural History in Brussels (originally Oterognathus houzeaui Dollo 1889); a smaller (around 4.5 m. (15 ft.) long) species from Belgium.
Plioplatecarpus primaevus [prie-MEE-vuhs] Russell 1967
"young": indicating the earliest recorded species of Plioplatecarpus,
from the Lower Pierre Shale of South Dakota, based on a right quadrate,
scapulocoracoids and three thoracic vertebrae (Holotype: USNM 18254). A new,
almost complete specimen (NMC 21853) from the Bearpaw Formation of Saskatchewan,
Canada, is attributed to the species (Holmes 1996), and along with other new
material, including embryos (Bell, Sheldon, Lamb & Martin 1996) found in the
pelvic region of an adult skeleton unearthed in South Dakota. About 3.3 m (12
ft.) long. Plioplatecarpinae Late Cretaceous (Campanian-Maastrichtian) NA.,
Plotosaurus Camp 1951 "swimmer lizard"*
PLOT-o-SAWR-uhs (Gr. plotes "swimmer" + Gr. sauros "lizard") (m) named to indicate a highly adapted swimming reptile (new name to replace preoccupied Kolposaurus Camp). Plotosaurus is a very derived (advanced) mosasaur, with many similarities to ichthyosaurs: a slender and elongate skull with exceptionally large orbits and nares; narrow, elongated ichthyosaur-like paddles (notable for many extra phalanges); a deep, shortened, relatively rigid midsection; extreme reduction of chevrons and zygapophyses; and a tail with an enlarged, flattened end formed from raised neural spines. It was probably among the fastest swimming mosasaurs, with large eyes for keen eyesight. It may have hunted swift moving surface fish--fossilized stomach contents indicate a fish diet. Camp thought it frequented the near-shore (thus the original name Kolposaurus "bay lizard").
Vertebrae: 51 presacrals / 30 pygals / 5 intermediate caudals with
chevrons and transverse processes / 64 terminal caudals
Length: (P. tuckeri) 13 m. (43 ft.); skull: 59 cm (24 in.)
Type Species: Plotosaurus bennisoni [ben-i-SOH-nie] (Camp
1942): for Allan Bennison, a
Plotosaurus tuckeri [TUHK-uhr-ie] (Camp 1942) for W.M. Tucker of
Fresno State College, who found a long series of its vertebrae (Holotype: UCMP
33913) in the Moreno Formation,
Pluridens Lingham-Soliar 1998 "many teeth"*
PLOOR-i-denz (Lat. pluris (plus) "more, many" + Lat. dens "tooth") (m) named for the large number of teeth (28+) in its lower jaw, one and a half times the number recorded in any other known mosasaur; known from an isolated almost complete dentary bone (Holotype: BMNH R14153) from the Farin-Doutchi Formation near Mount Ilatarda, Niger and a referred dentary (BMNH R9804), found in the Nkporo Formation (Campanian-Maastrichtian) near Calabar, southern Nigeria, West Africa. Pluridens was a moderately large mosasaur (estimated 8-9 m (25-30 ft.) long). The unusual number of rather small, close-fitting, uniform teeth and relatively long, slender jaw suggests a diet similar to early ichthyosaurs such as Temnodontosaurus. Pluridens may have been an ambush predator adapted to a shallow sea and lagoonal environment, specialized for feeding on small fish and thin- shelled mollusks.
Type Species: Pluridens walkeri [WAW-kuhr-ie] Lingham-Soliar
1998 for Cyril A. Walker, to mark his contributions as a vertebrate
paleontologist at the
Prognathodon Dollo 1889 "forward-jaw tooth"
prog-NATH-o-don (Gr. pros "forward, before" + Gr. gnathos
"jaw" + Gr. odon "tooth") (m) named for
"its procumbant premaxillary teeth, projecting forward from the bone that
contains them" in the upper jaw. The projecting teeth in some species may
indicate a diet of shellfish scooped off the seafloor, similar to placodonts.
The skull is akinetic, with relatively short and heavy jaws, and a broad blunt
snout (unlike the pointed snout of most mosasaurs). The moderately swollen,
generally straight and sometimes heavily grooved conical teeth "are better
adapted to crushing than in any mosasaur except Globidens" (Russell
1967). The pterygoid teeth on the upper palate are very large (unlike the absent
or rudimentary pterygoid teeth in Globidens). The vertebrae have
functional zygosphenes and zygantra; haemal chevrons are fused to the caudal
vertebrae. No skeletons known so far provide a relatively complete set of
vertebrae. Researchers have generally classified Prognathodon in the
Length: 6-10.5 m. (20-34 ft.); skull: 60 cm. (2 ft.)
Type Species: Prognathodon solvayi [sol-VAY-ie] Dollo
1889: for Ernst Solvay, a Belgian technochemist who founded the Solvay
Institute--most of the bones originally described (a nearly complete skull,
incomplete postcranial skeleton with vertebrae, fragments of scapula and
coracoid (Holotype: IRSNB R33(4672))) were found on the institute's property in
Prognathodon giganteus [ji-GAN-tee-uhs or ji-gan-TEE-uhs] Dollo 1904 "gigantic"; a large European species up to 10 m. (33 ft.) long in length, with smooth enamel on its teeth. skull est. 85 cm.
Prognathodon overtoni [oh-vuhr-TOH-nie] (Williston 1897): for T. R. Overton, S. W. Williston's laboratory assistant, who collected the type specimen; originally called Brachysaurus overtoni Williston 1897; a medium to large species, with non-procumbant anterior teeth and smooth enamel, from the Pierre Shales in South Dakota; skull est. 70 cm.
Prognathodon rapax [RAP-aks] (Hay 1902) "rapacious"; an incompletely known North American species with a distinctive quadrate, which has a large tuberosity on the anteromedian edge of the shaft.
Prognathodon stadtmani [STAT-muh-nie] Kass 1999: for Kenneth
Stadtman, curator of the Brigham Young University Earth Science Museum; a large
species distinguished by the shape of the coronoid bone and an edentulous
anterior projection of the dentary bone. Known from an incomplete skull and
skeleton (Holotype: BYU 13082) found in the Mancos Shale near Cedaredge, western
Prognathodon waiparaensis [WIE-puhr-uh-EN-sis] Gregg &
Welles 1971 "from Waipara (River),"
Prognathosaurus Dollo 1889 "forward jaw lizard"
PROG-na-tho-SAWR-uhs (Gr. pros "first, foward" + Gr. gnathos "jaw" + Gr. sauros "lizard") (m) named for "its procumbant premaxillary teeth, projecting forward from the bone that contains them"; unnecessary replacement name for Prognathodon Dollo, supposedly preoccupied by Prognathodus Edgerton. [= Prognathodon]
Pterycollosaurus Dollo 1882 "fused-pterygoid lizard" ter-i-KOL-o-SAWR-uhs (irr. ptery(goid), wing-shaped bone in the skull + Gr. kolla "glue" + Gr. sauros "lizard") (m) from Goldfuss's description of the skull of Mosasaurus maximiliani, indicating that the pterygoid bone was supposedly fused to the nasal bones, a condition not found in other mosasaurs. Goldfuss's description was in error. [= Mosasaurus]
Pythonomorpha Cope 1869 "python forms"
pie-THON-o-MOR-fuh (Gr. Python, a giant serpent killed by Apollo + Gr. morphe "form" + -a) (n) Cope rejected widely accepted ideas about the classification of mosasaurs. Cuvier thought Mosasaurus was most closely related to monitor lizards--a view still held by most modern researchers. Owen in turn supported a classification of mosasaurs among lizards, as did Marsh--although as a distinct suborder Marsh called the Mosasauria. Cope, however, recognized affinities to lizards, plesiosaurians and especially to snakes in the mosasaurs, and placed them in a separate order of reptiles, explaining: "In the mosasauroids, we almost realize the fictions of snake-like dragons and sea-serpents, in which men have been every prone to indulge. On account of the ophidian part of their affinities, I have called this order Pythonomorpha." Cope's original vision of "pythonomorphs" was highly imaginative, and inaccurate in many details--he thought that the creatures had a single "pair of powerful paddles in front," and that "the body was snake-like, with narrow chest and neck scarcely differing in diameter. They were immensely elongate...", in some cases approaching one hundred feet. In a bout of monster fever, Cope deemed it probable that: "terrestrial representatives now unknown to us, inhabited the forests and swamps of the Mesozoic continents, and strove for mastery with the huge dinosaurs"--no such land-living pythonomorphs have ever been found. On the scientifically substantiated side, discoveries of complete specimens of mosasaurs showed the animals had a pair of hind paddles, and were much less elongated and serpentine in appearance than Cope surmised. Partly in response to this better understanding of mosasaur anatomy, Cope's theory of a close affinity between snakes and mosasaurs was widely dismissed and almost universally ignored by 20th century researchers, who favored a burrowing rather than an aquatic origin for snakes. In a major taxonomic twist, however, some researchers (Lee 1997; Caldwell & Lee 1997) have revived Cope's old idea, creating fresh controversy. Although some of the features Cope used to link snakes and mosasaurs are no longer considered valid, his fundamental insight may be sound: mosasaurs and snakes appear to share unique similarities in their teeth, skulls and vertebrae that set them apart from varanoid lizards. Lee has redefined the category Pythonomorpha as "The most recent common ancestor of mosasauroids and snakes, and all its descendants," thus including Cope's original Pythonomorpha (a synonym of the Mosasauridae), the aigialosaurs, coniasaurs and the Serpentes (snakes). It seems that a number of enigmatic snake-like marine squamates from the Early Cretaceous such as Simoliophis "Cretaceous snake," could belong in the redefined Pythonomorpha as well, or even qualify as true snakes, though new formal studies have yet to be published. Other researchers (Zaher & Rieppel 1999; American Museum Novitates 3271) have recently disputed the close mosasaur- snake relationship, citing the mode of tooth-attachment to the jaw, which they see as fundamentally different in the two groups. [clade]
Rhamphosaurus Cope 1872 "beak lizard"
RAM-fo-SAWR-uhs (Gr. rhamphos "beak" + Gr. sauros "lizard") (m) proposed replacement for preoccupied Rhinosaurus Marsh; preoccupied by Rhamphosaurus Fitzinger. See Tylosaurus. [= Tylosaurus]
Rhinosaurus Marsh 1872 "snout lizard"
RIEN-o-SAWR-uhs (Gr. rhin- (rhis) "nose, snout" + Gr. sauros "lizard")* (m) alluding to "an elongate cylindrical muzzle, that projects some distance in front of the teeth" (Preoccupied by Rhinosaurus Gray 1845. See Tylosaurus) [= Tylosaurus]
Rikisaurus Wiffen 1990 "small lizard"
RIK-i-SAWR-uhs (Maori riki "small" + Gr. sauros
"lizard") (m) named to indicate a "small adult mosasaurine"
Saurochampsa Wagler 1830 "lizard crocodile"
SAWR-o-KAMP-suh (Gr. sauros "lizard" + Gr. champsa "crocodile") (f) [= Mosasaurus]
Selmasaurus Wright & Shannon 1988 "
Type Species: Selmasaurus russelli [RUH-sel-ie] Wright & Shannon 1988: for Dale A. Russell "for his extensive work on the Mosasauridae." Plioplatecarpinae Late Cretaceous (Campanian) NA.
See also Selmasaurus johnsoni Polcyn and Everhart 2008
Sironectes Cope 1874 "rope swimmer"
SIE-ro-NEK-teez (Gr. seira "rope, chain" + Gr. nektes "swimmer") (m) alluding to the supposed "elongate snake-like form" of mosasaurs; Cope greatly exaggerated the sinuous shape of mosasaurs in his inaccurate early conceptions; based on a partial specimen of Platecarpus. [= Platecarpus]
Taniwhasaurus Hector 1874 "Taniwha lizard" ("water-monster lizard")
TUHN-i-fuh-SAWR-uhs (Maori taniwha, a dragon-like water monster
+ Gr. sauros "lizard") (m) named for Taniwha, a
dragon-like sea- monster in Maori mythology, to indicate a mosasaur found in New
Zealand. Welles and Gregg (1971) revised the material and designated a lectotype
(Lectotype: DM R1536): a well-preserved partial skull from Haumuri Bluff,
Type Species: Taniwhasaurus oweni [OH-wen-ie] Hector
1874: for Sir Richard Owen (1804-1892), British paleontologist and comparative
anatomist, who first described Mesozoic marine reptiles from
Tylosaurinae Williston 1897 "Tylosaurus subfamily"
tie-lo-saw-RIE-nee (Tylosaurus + -inae) (fem. plural) subfamily of the Mosasauridae containing large, highly predatory short- bodied mosasaurs notable for a "ram" snout--a toothless bony extension of the upper and lower jaws. Zygosphenes and zygantra are rudimentary or absent on vertebrae. The tail is relatively long, without a fin; the haemal arches on the underside of the tail are not fused with the centra. The humerus, radius and ulna are long (a primitive trait) but the carpal elements are reduced and the number of phalanges greatly increased. Lingham-Soliar (1992) saw evidence that tylosaurines were neither the fastest swimmers nor the physically strongest mosasaurs--instead, they were lightly built, with a massive reduction in body weight, relatively small limb girdles and paddles, and highly cancellous bones (probably impregnated with fat in life for buoyancy). Such features suggest tylosaurines relied on shark-like stealth and ambush, using a sudden, short burst of speed to strike at prey rather than long pursuits.
Members: Tylosaurus (type genus); Hainosaurus, Taniwhasaurus
Tylosaurus Marsh 1872 "knob (snout) lizard"
TIE-lo-SAWR-uhs (Gr. tylos "protuberance, knob" + Gr. sauros "lizard")* (m) named for "an elongated cylindrical muzzle," or rostrum, projecting beyond the frontmost teeth in the upper jaw; new generic name to replace preoccupied Rhinosaurus Marsh. The tip of the snout was similar in function to the "ram" or "beak" (Gr. embolon or proembolos; Lat. rostrum) that the ancient Greeks and Romans mounted on the prow of warships to ram and sink enemy vessels--older paleontological literature often referred to Tylosaurus as the "ram-nosed lizard" based on the analogy. Tylosaurus likely used its "ram" snout to stun prey, defend against sharks or other predators, and probably to battle rivals of its own species. One specimen has the tip of the snout deformed into a mushroom shape as a result of injury and infection.
Tylosaurus is a very large, highly predatory mosasaur known from a
number of complete skeletons and skulls, though the holotype skull from the
Vertebrae: 29-30 presacrals/ 6-7 pygals/ 33-34 caudals with chevrons /
56-78 terminal caudals
Length: (T. proriger) 10-12.3 m. (33-40 ft.); skull:1-1.3 m (3.3- 3.5 ft.)
Type Species: Tylosaurus proriger [PROHR-i-jer] (Cope 1869) "prow-bearing": referring to "the cylindrical prolongation of the premaxillary bone beyond the teeth and a similar flat prolongation of the extremity of the dentary" (Cope 1869), as Macrosaurus proriger Cope 1869; based on a partial skull and vertebrae from western Kansas "in the Museum of Comparative Zoology, Cambridge, Mass., brought by Prof. Agassiz from the Cretaceous beds in the neighborhood of Monument, Kansas, and near the line of the Kansas Pacific Railroad." (Cope 1875) The holotype specimen is apparently lost. (Santonian-Campanian)
Additional Species: Tylosaurus nepaeolicus [nep-ee-OL-i-kuhs] (Cope 1874) "from the Nepaholla River": derived from an alternate spelling of Nepaholla, an old name for the Solomon River in north central Kansas, near where the type fossils were found (Niobrara Formation); an earlier (Coniacian), smaller, more primitive species differing from Tylosaurus proriger in some features of the skull (Holotype: AMNH 1565). (estimated length: 7 m. (24 ft.); skull: 63 cm. (2.1 ft.)) (Coniacian). A much larger specimen has been found but not yet described (Mike Everhart, personal communication).
See also Tylosaurus kansasensis Everhart 2005
NOTE: A new species of Tylosaurus from the Late Coniacian of North
America will be described soon. "Tylosaurus haumuriensis"
from the Maastrichtian of New Zealand is a now considered a synonym of Taniwhasaurus
oweni . Tylosaurinae Late Cretaceous (Coniacian-Campanian) NA., Afr.,
Yaguarasaurus Paramo 1994 "Yaguara (people) lizard"
yah-GWAHR-uh-SAWR-uhs (Yaguara (a Native American people) + Gr. sauros
"lizard") (m) named for the Native American Yaguara people, who
inhabited the region in western central Colombia where the specimen was found (Villeta
Formation limestone (Upper Turonian), near the village of Yaguara, Huila
Department). Yaguarasaurus is a small plioplatecarpine, known from a
nearly complete skull and mandible, plus the atlas, axis and first cervical
vertebra, two anterior dorsal vertebrae and rib fragments (Holotype: BRV-68
(Paleontological Collections of the Department of Geosciences of the National
University of Colombia, Bogota)); additional parts of the skeleton may be lie
unexposed at the site at an angle difficult to excavate. It has a highly kinetic
skull, but differs from other plioplatecarpines in the proportions and form of
the frontals and other cranial bones. The vertebrae have well developed zygantra
and zyosphenes. The recurved and striated teeth suggest a diet of both
vertebrates (fish) and invertebrates (ammonites) of similar size. Yaguarasaurus
is the first mosasaur found in
Length: (estimated) 4.7-5 m. (16-16.6 ft.); skull: 47 cm. (to occiput)/ 54.5 cm. (to squamosal).
Type Species: Yaguarasaurus colombianus [ko-LOM-bee-AY-nuhs]
Parano 1994; for