Information of Spencer G. Lucas, Ph.D.

New Mexico Museum of Natural History and Science:

 
 

Information of Dr. Evgeny V. Popov, Department of Paleontology:

You will find some papers (free download) of Information of here: http://cretaceous.ru/people/popov/

The Family Cetorhinidae Gill, includes one extant genus, Cetorhinus Blainville, and a single living species, the basking shark, C. maximus (Gunnerus). Excluding Pseudocetorhinus Duffin, a questionable cetorhinid from the Late Triassic of Europe, the oldest cetorhinids are found in the middle Eocene of Antarctica, the Eocene of Oregon, and possibly the Eocene (Bartonian-Priabonian) Tavda Formation, west Siberia, Russia. The genus Cetorhinus has previously included only one valid extinct species, C. parvus Leriche, a small Oligocene to middle Miocene shark from marine sediments of Europe, and possibly the late Oligocene of South Carolina, U.S.A. Late Miocene through Pleistocene basking sharks from Europe, Japan, Chile, California and Oregon, are generally referred to the Recent species, C. maximus, or just identified as Cetorhinus sp. 

For purposes of comparison with fossil cetorhinids, the gill rakers, teeth, and vertebrae of C. maximus are described and illustrated. The basking shark dentition shows weak gradient monognathic heterodonty in upper and lower jaws, weak dignathic heterodonty, no evidence of disjunct monognathic heterodonty in either jaw, strong ontogenetic heterodonty in both sexes, and no dental sexual dimorphism. The occurrence of abnormal teeth, especially in the upper dental series, is relatively common. 

The most primitive known cetorhinid has been discovered in deep water (bathyal), late Eocene sediments of the Keasey Formation, Columbia County, Oregon, U.S.A. The specimen, consisting of a partial associated skeleton, with 11 vertebrae, 5 gill rakers, and 22 teeth, and a second grill raker association from the same formation, form the basis for description of a new genus and species, Keasius taylori. The Oligocene-early Miocene species Cetorhinus parvus, is referred to the genus Keasius, and diagnoses for the Family Cetorhinidae, genus Cetorhinus, and species K. parvus, are emended to accommodate new information on the heterodonty, gill rakers and vertebral calcification patterns found in K. taylori. In most characters of its teeth, vertebrae, and gill rakers, K. taylori is more ancestral than Cetorhinus maximus, and is closely related to K. parvus. Based on dental reconstructions, K. taylori has an ancestral lamnoid dental formula, lacks the derived secondary homodonty of C. maximus, possesses moderate dignathic heterodonty, and moderate disjunct monognathic heterodonty in both jaws. Keasius taylori is interpreted to have dental bullae in both jaws. Among modern macrophagous lamniforms, the dentition of K. taylori resembles most closely that of the Lamnidae, and specifically Lamna. The vertebral calcifications found in centra of K. taylori most closely resemble the lamnoids, Isurus oxyrinchus and L. nasus, and the alopiid, Alopias superciliosus, but not Carcharodon carcharias, A. vulpinus, A. pelagicus, or any other extant lamniform species. The gill raker morphology of K. taylori is ancestral relative to those of the Oligocene K. parvus, or Miocene and younger Cetorhinus. Gill raker size increases from the Eocene to Recent. Keasius taylori was certainly microphagous, but may have been macrophagous as well. The holotype individual of K. taylori appears to be about 15 years old, based on counts of growth band increments on the corpus calcareum of seven centra.

Feb. 1, 2013 — Researchers from Nova Southeastern University (NSU) are conducting a unique scientific study of bacteria found in the mouths of sharks to develop better medical treatment methods for shark bites victims.

Scientists from NSU's College of Pharmacy working in collaboration with St. Mary's Medical Center will be gathering data from sharks captured during The Blacktip Challenge, a 72-hour South Florida fishing tournament to fish blacktip sharks from the beach. The tournament runs from Jan. 30 to Feb. 3.

In the last decade, Florida has consistently ranked amongst the highest worldwide in the number of shark attacks. The Sunshine State has accounted for about 25 percent of the approximate 100 incidents of reported shark bites a year.

Because of this, NSU researchers believe their findings are critical in helping the millions of ocean-goers each year that share the beaches and waterways with sharks. Their research, the first of its kind in the United States, could lead to groundbreaking research that will ultimately save lives from this tragedy.

"We are excited to gather scientific data from these incredible animals in order to learn more about the infecting bacteria from their bites and how to treat victims," said Nathan Unger, Pharm.D., an assistant professor at NSU's College of Pharmacy and the lead researcher on this project.

Story Source: Science Daily http://www.sciencedaily.com/releases/2013/02/130201132202.htm

enlarge
Tiger Shark swims by at Tiger Beach in the Bahamas. (Credit: iStockphoto/Amanda Cotton)

Jan. 30, 2013 — A cluster of tapeworm eggs discovered in 270-million-year-old fossilized shark feces suggests that intestinal parasites in vertebrates are much older than previously known, according to research published Jan. 30 in the open access journal PLOS ONE by Paula Dentzien-Dias and colleagues from the Federal University of Rio Grande, Brazil.

Remains of such parasites in vertebrates from this era are rare- of 500 samples examined, only one revealed the tapeworm eggs. This particular discovery helps establish a timeline for the evolution of present-day parasitic tapeworms that occur in foods like pork, fish and beef.

The fossilized eggs were found in a cluster very similar to those laid by modern tapeworms. Some of them are un-hatched and one contains what appears to be a developing larva. According to the study, "This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was previously known and occurred at least 270-300 million years ago."

The fossil described in this study is from Middle-Late Permian times, a period followed by the largest mass extinction known, when nearly 90% of marine species and 70% of terrestrial species died out.

Financial support was provided by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico -- Brazil (CNPq) through a study grant (PCD-D, AEQF and BH) and the Project 478914/2006-7 (Edital MCT/CNPq 02/2006 -- Universal). This work was also partially funded by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico through scholarships granted to AEQF, BH and CLS.

Story Source: Science Daily http://www.sciencedaily.com/releases/2013/01/130130184200.htm

 

Journal Reference:

1. Paula C. Dentzien-Dias, George Poinar, Ana Emilia Q. de Figueiredo, Ana Carolina L. Pacheco, Bruno L. D. Horn, Cesar L. Schultz. Tapeworm Eggs in a 270 Million-Year-Old Shark Coprolite. PLoS ONE, 2013; 8 (1): e55007 DOI:10.1371/journal.pone.0055007