Douglas J. Long

Sharks from the La Meseta Formation (Eocene), Seymour Island, Antarctic Peninsula

ABSTRACT The marine waters of present-day Antarctica contain an exceedingly depauperate elasmobranch fauna. Recent investigations into the Eocene marine sediments of the La Meseta Formation of Seymour Island, Antarctic Peninsula yielded 13 fossil sharks new to the Antarctic region. Two, Stegostoma cf. S. fasciatum and Pseudoginglymostoma cf. P. brevicaudatum, were unknown as fossils. Squalus woodburnei, S. weltoni, and Anomotodon multidenticulata are new species. Heptranchias howelli, Centrophorus sp., Deania sp., Dalatias licha, Odontaspis rutoti, O. winkleri, Lamna cf. L. nasus, and Scoliodon sp. are reported in Antarctica for the first time. In addition, the new fossil shark material increases the representation of the four previously known fossil sharks from Seymour Island: Squatina sp., Pristiophorus lanceolatus, Carcharias macrota, and Carcharocles auriculatus.

Sightings and Strandings of Guadalupe Fur Seals in Central and Northern California, 1988–1995

The Guadalupe fur seal ( Arctocephalus townsendi ) was hunted to near extinction before its natural history was well known. The last known population is currently centered on Guadalupe Island, Mexico, but in recent years northern extralimital records from California have become more frequent. We report 14 new records (3 adults, 11 juveniles) of Guadalupe fur seals stranded (nine) or sighted (five) along the central and northern coast of California. These northern records appear to correspond with El Nino events, seasonal currents in California, and to dispersal behavior in this species. Dietary items retrieved from stomachs and feces included otoliths from Citharichthys sordidus, Lampanyctus, Protomyctophum , and Scopelogadus , and beaks of the squids Loligo opalescens, Gonatopsis , and Onychoteuthis borealojaponica . Emaciation commonly was associated with stranding, but other findings included an umbilical hernia, septicemia, and bacterial pneumonia. Three of the stranded individuals had experienced entanglement in fishing gear or marine debris.

An Eocene wrasse (Perciformes; Labridae) from Seymour Island

A nearly complete lower pharyngeal tooth-plate from a large (over 60 cm long) fossil wrasse (Perciformes: Labridae) was recently recovered from the middle to late Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula. This find increases the number of teleosts from the Eocene of Antarctica to five taxa, and further illustrates the diversity of the ichthyofauna in the Eocene Weddellian Sea prior to wide-scale climatic change in the Southern Ocean. The fossil wrasse represents the first occurrence of this family in Antarctica, and is one of the oldest fossils of this family from the Southern Hemisphere. Wrasses are not found in Antarctic waters today, and probably became extinct during the Oligocene due to a combination of climatic change, loss of shallow-water habitat, and changes in the trophic structure of the Wedell Sea.

A new clade of putative plankton-feeding sharks from the Upper Cretaceous of Russia and the United States

ABSTRACT Eorhincodon casei from Russia and Megachasma comanchensis from the United States are two Cretaceous taxa initially described as putative planktivorous elasmobranchs, but the type specimens of these two taxa were subsequently reinterpreted to represent taphonomically abraded teeth of an odontaspidid, Johnlongia Siverson (Lamniformes: Odontaspididae). Here, we redescribe the type materials of ‘E. casei’ and ‘M. comanchensis’ and describe additional specimens of these species from other Late Cretaceous localities in Russia and the United States. These specimens demonstrate that (1) the two fossil taxa are valid species; (2) they warrant the establishment of a new genus of presumed planktivorous sharks, Pseudomegachasma, gen. nov., to accommodate the two species; and (3) the new genus is sister to Johnlongia and together constitute a new subfamily Johnlonginae, subfam. nov., tentatively placed in the family Odontaspididae sensu stricto. This taxonomic placement indicates that the putative planktivorous clade was derived from a presumed piscivorous form (Johnlongia), with an implication that Pseudomegachasma, gen. nov., evolved a plankton-eating habit independent of the four known planktivorous elasmobranch clades (Rhincodontidae, Megachasmidae, Cetorhinidae, and Mobulidae). It also indicates that planktivorous diets evolved independently at least three times in the order Lamniformes (i.e., Megachasmidae, Cetorhinidae, and Odontaspididae), and more significantly, Pseudomegachasma, gen. nov., would represent the oldest known plankton-feeding elasmobranch in the fossil record. The present fossil record suggests that Pseudomegachasma, gen. nov., evolved in a relatively shallow-water environment in Russia in the early Cenomanian or earlier and subsequently migrated to the North American Western Interior Seaway by the mid-Cenomanian.

A NEW WORLD OCCURRENCE OF NOTIDANODON LANCEOLATUS (CHONDRICHTHYES, HEXANCHIDAE) AND COMMENTS ON HEXANCHID SHARK EVOLUTION

Notidanodon lanceolatus Woodward is reported from Late Aptian strata of northern California. This specimen, the oldest fossil cow shark (Hexanchidae) in the New World, greatly extends the geographic distribution of this species and confirms the eurytopic distribution of this genus. We suggest that cow shark teeth evolve in an orderly sequence in which the mesial edge of the tooth is at first smooth (Notidanus muensteri), then serrate (Notidanus serratus, Notorynchus aptiensis), and finally dentate (Notidanodon lanceolatus).

A New Fossil Megamouth Shark (Lamniformes, Megachasmidae) from the Oligocene—Miocene of the Western United States

ABSTRACT The extant megamouth shark, Megachasma pelagios (Lamniformes: Megachasmidae), is a large filter-feeding fish. We here describe a new species of Megachasma, M. applegatei, sp. nov., a putative sister species of the extant M. pelagios, based on isolated teeth from late Oligocene—early Miocene (late Chattian—Aquitanian) marine deposits in California and Oregon, U.S.A. Although showing a megachasmid tooth design, teeth of M. applegatei, sp. nov., exhibit a wide morphological range and are reminiscent to those of odontaspidid sharks with strong heterodonty. Megachasma applegatei, sp. nov., could have commonly measured approximately 6 m in total length and likely had a wide range of diet, possibly including small fishes and planktonic invertebrates. The fossil record indicates that either M. applegatei, sp. nov., was broadly adapted to a wide bathymetric tolerance or was a nektopelagic feeder over both deep and shallow water habitats.

Tropical Eastern Pacific Records of the Prickly Shark, Echinorhinus cookei (Chondrichthyes: Echinorhinidae)

Abstract: Most records of the prickly shark, Echinorhinus cookei Pietschmann, 1928, are from temperate and subtropical areas of the Pacific rim, with few records from the tropics. This seemingly disjunct distribution led some authors to consider E. cookei to have an antitropical distribution. Unreported museum specimens and underwater observations of E. cookei from Cocos Island, Costa Rica; the Galápagos Islands; and northern Peru confirm its occurrence in the tropical eastern Pacific and, combined with other published records from the eastern Pacific, establish a continuous, panhemispheric eastern Pacific distribution.

A new species of the deepwater cardinalfishEpigonus (Perciformes: Epigonidae) from the Galápagos Islands

A new species of deepwater cardinal fish,Epigonus merleni, is described from a specimen found floating at the sea surface as a result of the eruption of Fernandina Volcano, Isla Fernandina, Galápagos Islands. It differs from all knownEpigonus in having the greatest number of lateral line scales (57) and the fewest gill rakers (17), as well as in several other characters.

The ectoparasitic barnacle Anelasma(Cirripedia, Thoracica, Lepadomorpha) on the shark Centroscyllium nigrum (Chondrichthyes, Squalidae) from the Pacific sub-Antarctic

We report the occurrence of the ectoparasitic lepadomorph barnacle Anelasma sp. on the deep-sea squaloid shark Centroscyllium nigrum from the Pacific sub-Antarctic off southern Chile. Anelasma has previously been documented only from the northeast Atlantic on the squaloid shark Etmopterus spinax; this new record extends the known range of Anelasma into the Pacific Ocean and into the Southern Hemisphere, and documents a new host for this parasitic barnacle.

Flight Feather Molt of Turkey Vultures

Abstract We document the molt sequence of flight feathers in Turkey Vultures (Cathartes aura) based on studies of captive and wild birds, and examination of museum specimens. We found an unusual pattern of primary replacement, which appears to be a modified form of Staffelmauser, or stepwise wing molt. A Staffelmauser-like strategy for replacement of the secondaries is also described. These patterns of feather replacement appear to be adaptations to maintain flying performance while replacing all primaries and most secondaries during each molt. To what extent molt patterns in Turkey Vultures reflect convergent adaptation for flight, rather than ancestral characters useful for phylogenetic studies, remains unknown.