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Abstracts of AES Scientific Papers

American Elasmobranch Society 1999 Annual Meeting
State College, Pennsylvania
ABSTRACTS - Part 1: Acher through Fluharty
Acher, Roger

Lab Biological Chemistry, University of Paris VI, Paris, 75006 France

Organismal versus molecular evolution. Insights into Chondrichthyes.

The main theories of evolution, Lamarckim (adaptation) and Darwinism (natural selection), were conceived during the XIXth century from studies made at the organismal level. At present, deciphering of complete genomes and proteomes leads to a definition of the species in molecular terms. Molecular phylogenetic trees, constructed on the percentages of substitutions in nucleic acid and protein sequences, are confronted to morphological trees derived from taxonomy. However, the substitution rates greatly vary from a protein to another and, in a given protein, from a domain to another. Protein shapes, determined by aminoacid sequences through self-folding, evolve following rules different from those governing body evolutions. Molecular clocks are usually not in agreement with divergence times between lineages estimated through fossil records. Furthermore new evolutionary mechanisms, such as genetic drift (neutral evolution), genomic drive, horizontal gene transfer, have been hypothesized. Evolution of Chondrichthyes differ sharply from that of bony vertebrates by several specific features (skeleton, osmoregulatory strategy, reproduction). The osmoregulatory system implies four organs: gut, kidney, gills and rectal gland. Regulation of nephron cells involves a cascade of molecule interactions : mediators, receptors, transductors and effectors. A great diversity is found in neurohypophysial hormones when compared to those of bony vertebrates, whereas, among effectors, Squalus acanthias urea transporter and CFTR-chloride channels exhibit, respectively, 61% and 72% sequence identity with their human counterparts. Evolution of the osmoregulatory function was apparently made more by changes in the combinatorial coordination of effectors in target cells rather than modifications in the molecules themselves. 


*Amesbury, Elena, Buhi, William C., Craine, D. Andrew, Guillette, Jr., L. J., Evans, David H.

(EA, LJG) Department of Zoology, University of Florida, Gainesville, FL 32611; (WCB) Department of Obstetrics and Gynecology, University of Florida, College of Medicine, Gainesville, FL 32610; (DAC) Department of Biology, Maryville College, Maryville, TN 37804; (DHE) Department of Zoology; University of Florida, Gainesville, FL 32611

Uterine fluid and serum protein composition and serum steroid hormone concentrations during gestation in the aplacental viviparous Atlantic stingray, Dasyatis sabina

The Atlantic stingray,  Dasyatis sabina, is an aplacental viviparous elasmobranch. Embryos have an external yolk sac which is quickly depleted within the first few weeks of a 12-14 week gestation. Uterine fluid is produced shortly after ovulation, and continues to be produced until parturition. We test the hypothesis that this fluid contains unique proteins that are synthesized and secreted by the uterus, and that the changing protein composition is correlated with varying serum steroid hormone concentrations. To test this hypothesis, blood and uterine fluid samples were collected from rays during the annual reproductive cycle. Uterine fluid and serum proteins were characterized by isoelectric point (pI) and molecular weight using two dimensional gel electrophoresis. Uterine fluid from early through late gestation contained a series of basic (pI 7-8) and acidic (pI 4-5) proteins ranging from 30-220 k molecular weight. A large acidic protein (pI 5) first appeared in mid-gestation uterine fluid, and was present through late-gestation. Serum 17-ß estradiol concentrations significantly increased from 426 +/- 78 pg/ml early gestation to 8293 +/- 2165 pg/ml mid-gestation, and remained elevated through late gestation. Serum testosterone concentrations increased from 78 +/- 8 pg/ml during early gestation to 279 +/- 19 pg/ml during mid-gestation. 


*Amesbury, Elena, Wyffels, Jennifer, Wourms, John P., Snelson, Jr., Franklin F., Bodine , A. B.

(EA) Department of Zoology, University of Florida, Gainesville, FL 32611; (JW) AVS Department, Clemson University, Clemson, SC 29634; (JPW) Department of Biological Science, Clemson University, Clemson, SC 29634; (FFS) Department of Biology, University of Central Florida, Orlando, FL 32816; (ABB) AVS Department, Clemson University, Clemson, SC 29634

Morphology of the uterus during the annual reproductive cycle of the aplacental viviparous Atlantic stingray, Dasyatis sabina

The Atlantic stingray,  Dasyatis sabina, is an aplacental viviparous elasmobranch that reproduces annually. In our study population, ovulation occurred in April, and gestation lasted approximately 14 weeks. Villous extensions of the uterine mucosa line the inner wall and are present throughout the year. Prior to ovulation, during the final stages of oogenesis, the uterus was aglandular. Villus length averaged 3.7 +/- 0.7 mm. The uterine morphology transformed dramatically during gestation. Uterine villi were differentiated when encapsulated embryos were developing in the uterus. Shallow tubular glands were present in villi, and deep tubular glands were present in the uterine mucosal lining. Uteri containing unencapsulated, early gestation stage embryos were completely glandular. The uterus was fully glandular through mid- and late gestation. Villi length significantly increased to 6.9 +/- 0.6 mm during early gestation, and length remained similar through mid- and late gestation. Vascularization increased and capillaries hypertrophied during early and mid-gestation. Lipid droplets accumulated within glandular pits mid- and late gestation. The uterine mucosa and villi were aglandular in the post-partum uterus, and villus length significantly decreased to 5.2 +/- 0.6 mm. 


Amorim, Alberto F., Arfelli, Carlos A., *Castro, José I.

(AFA, CAA) Av. Bartolomeu de Gusmao, Instituto de Pesca, Santos, Bahia 11030-906 Brazil; (JIC) Southeast Fisheries Science Center, NOAA/NMFS, Miami, FL 33149 USA

A juvenile megamouth shark Megachasma pelagios caught off southern Brazil.

The megamouth shark Megachasma pelagios is one of the rarest elasmobranchs. Since the capture of the first megamouth known to science in 1976, only about thirteen specimens have been reported, and only four have been available for scientific study. A juvenile megamouth shark was accidentally caught by the Brazilian longline vessel Tooshin Maru 106 off southern Brazil (27o 08'S 43o 55' W) on September 18, 1995. The specimen was hooked in the mouth at depth of 15-40 m over water approximately 1400 m deep. The specimen was recognized as unusual and donated to the Instituto de Pesca in Santos, Brazil. This is the first juvenile megamouth seen and studied by scientists. The specimen is an immature male 1800 mm TL (1448mm FL), weighing 24.4 kg. Morphologically, this specimen is very similar to other megamouth sharks described from the Pacific. The body is soft and flaccid, with poor vertebral calcification. The claspers are small and poorly developed, and the specimen is clearly a juvenile. The specimen is clearly countershaded, being black and brown above and white below. This specimen confirms the presence of megamouth in the Atlantic.


*Aubrey, Craig W., Snelson, F. F.

University of Central Florida, Orlando, FL 32816

Sharks of the inshore waters of the Canaveral Bight, Florida with emphasis on the spinner shark, Carcharhinus brevipinna 

Between September, 1995 and October, 1998, the sharks of the Canaveral Bight, Florida were qualitatively sampled during the summers between the beach and approximately 10 m depth. Preliminary observations indicated that the inshore waters in this area were being used as a nursery area by the spinner shark, Carcharhinus brevipinna. The objective of this study was to ascertain if spinner sharks are using these waters as a nursery area, and if so, to better understand  C. brevipinna life history parameters. Sharks were captured via hook and line from either a 5.9 m outboard boat or the Ocean Obsession II, a 21.4 m charter boat providing nightly shark fishing trips between May and October. Four hundred eighty-nine sharks representing three families and seven species were captured during the study. The Atlantic sharpnose shark,  Rhizoprionodon terraenovae, and the spinner shark were the most common species captured and appear to use these waters as a nursery area throughout the summer months. Spinners began arriving in June and were common into September and October. There was no difference in fork length (FL) between males and females. The 1997 spinners were larger those observed in 1998. Spinner pups grew about 10 cm FL during the summers of both 1997 and 1998. The lack of adult female spinner sharks and the failure to observe any young of the year spinner sharks with fresh umbilical remains lends support to Castro's (1993) statement that spinners appear to undergo parturition in deeper waters. Young of the year blacktip sharks, Carcharhinus limbatus, were observed but not in sufficient quantities to indicate that blacktips are selecting the inshore waters of the Canaveral Bight as a nursery area. A number of 1+ yr. juvenile  C. brevipinna  and  C.limbatus  sharks were captured in May and June of 1998. 


*Bergman, Ulrika, Connett, Stephen, Simpfendorfer, Colin, Hueter, Robert

(UB) Stockholm University, Vastervik, Sweden 59340 Sweden; (SC) St. George's School, Newport, RI 02840; (CS, RH) Center for Shark Research, Mote Marine Laboratory, Sarasota, FL 34236

A remarkably consistent fishery-independent measure of the relative abundance of large coastal and pelagic shark species inhabiting the northwestern Atlantic, 1976-1994.

The research vessel  Geronimo, owned and operated by St. George's School of Newport, Rhode Island, instituted a shark-tagging program in 1976 in collaboration with Jack Casey of the National Marine Fisheries Service Laboratory in Narragansett. The boat's longline gear, method of operation, and fishing area remained remarkably consistent through 1994, although annual fishing effort waned after the mid-1980's. The consistency of operation provides a continuous index of CPUE for sandbar Carcharhinus plumbeus, blue Prionace glauca, and other large coastal and pelagic species inhabiting New England shelf and canyon waters. In this region from 1976 to 1994, Geronimo's crew set a total of 37,631 hooks consistently deploying about 80 to 140 hooks per set, resulting in a total catch of 5,454 sharks. Reductions in CPUE over the nearly twenty-year period indicate the abundance of sandbar and blue sharks declined substantially during the 1980's, declines which match those from other studies. There was no apparent decline in average length of either sandbar or blue sharks caught during the period. Sex ratios in the catch of blue sharks show an approximately four-year cycle that may be indicative of segregated migratory habits of females vs. males.


*Bourdon, James A., Mollet, Henry F.

(JAB) New Jersey Paleontological Society, Croton-on-Hudson, NY 10520; (HFM) 886 Cannery Row, Monterey Bay Aquarium, Monterey, CA 93940

The dentition of the pelagic stingray Dasyatis violacea, its design and function. In both sexes, the pelagic stingray dentition combines high-cusped anterior files with broadly cuspidate teeth in posterior positions. The transverse ridges of these posterior teeth create a cutting edge. This is unlike the typical clutching-crushing design associated with most members of the genus. Based upon tooth and dentition design, and feeding observations at the Monterey Bay Aquarium, there appears to be sufficient evidence to characterize this as a deboning dentition. 


Carvalho, Marcelo

Department of Ichthyology, American Museum of Natural History, New York, NY 10024

A systematic revision of the electric ray genus  Narcine  Henle, 1834 (Chondrichthyes: Torpediniformes: Narcinidae).

The electric ray genus Narcine Henle, 1834 is revised and found to be more diverse than previously understood. Some 20 species are recognized from tropical and sub-temperate waters from all major oceans and seas of the world (except the eastern Atlantic Ocean and Mediterranean Sea), and new species are described. Species of Narcine  occur primarily in shallow to off-shore waters of continental shelf regions, but some species are known from upper continental slope areas as well. The Indo-West Pacific region is the most speciose but one of the most undersampled areas in which species of  Narcine  are known to occur. Many nominal species are placed in synonymy, some for the first time. A combination of proportional measurements, numerous counts and external and internal morphology were used to identify all valid species of Narcine . Difficulties surrounding taxonomic revisions of electric rays include the poor state of many specimens in preservative (including type-specimens), the misidentification of many nominal species by previous authors, and the great similarity among many species. Taxonomic revisions of the remaining electric ray genera are currently underway or have been completed. 


*Castro, Andrey, Rosa, Ricardo S.

Lab. de Ictiologia, Depto de Sistematica é ecologia, Universidade Federal da Paraíba, João Pessoa - PB, Paraíba 58059-900 Brazil

A Preliminary investigation of spatial distribution of Nurse shark at Atol das Rocas, Brazil.

The nurse shark Ginglymostoma cirratum, although widely distributed along the Brazilian coast, faces possible localized population declines, especially due to artisanal fishery impact. The goal of this study is to investigate some populational aspects of this species, and its distribution in the Biological Reserve of Atol das Rocas, only atol of South Atlantic. We carried out underwater observations at different parts of the area, recognizing the individuals through natural distinctive marks, like scars on their fins. A total of 92 nurse sharks was observed, of which 29 were individually identified. Most specimens (57 %) were found in tide pools. The maximum observed period of individual permanence in the pools was 22 days; three individuals moved among different pools in intervals of five days or less. Total length of the individuals varied from 45 to 350 cm, and average length in open areas of reserve was significantly higher than the one of specimens from closed areas (t=2.3918, p<0.05). Most specimens were young and their total length did not exceed 150 cm, rendering sex determination difficult. Mature specimens were only observed in open areas (TL>235 cm). 


Castro, José I.

Southeast Fisheries Science Center, NOAA/NMFS, Miami, FL 33149

Myths and misinformation about the nurse shark,  Ginglymostoma cirratum .

Although the nurse shark is an extremely common shallow-water species, abundant in Florida and the Caribbean, its biology is poorly known, and there are numerous myths and a great deal of misinformation about it in the literature. Although its name has been attributed to the making a "sucking sound" while feeding, it is actually derived from the name "huss", an ancient English name for a dogfish. The size and weight attained by the nurse shark has often been exaggerated, with claims of specimens 2130-3350 mm TL being common. None of the specimens measured in this study exceeded 2680 mm TL and 110 kg. None of the specimens actually measured by other researchers ever exceeded 2800 mm TL. The size at maturity is also often stated erroneously at about 1500 mm TL. Nurse shark females begin to develop sexually at about 2200 mm TL. In late spring, maturing females measuring 2360-2380 mm TL carried ripe oocytes 55-58 mm in diameter. Mating occurs primarily from mid-June to early July. The reproductive cycle of the nurse shark encompasses a five to six-month gestation cycle and a two-year ovarian cycle. A female will mate and ovulate in June of the first year. It then gestates for about five and a half months and gives birth in November or early December of that year. It will not mate again until about eighteen months later, in June of the second year. Thus, the reproductive cycle is biennial and a female produces a brood or litter every two years. The adult population of females could be divided into two groups during most of the year based on whether they were reproducing that year (carrying ripe oocytes or embryos) or they were post-partum.


*Chen, Che-Tsung, Chen, Sen-Lu, Cheng, I-Jiunn

National Taiwan Ocean University, Keelung 202, Taiwan R.O.C.

Temporal Variation of Heavy Metal Concentrations of  Galeus sauteri  (Carcharhiniformes: Scyliorhinidae) in the Northeastern Waters of Taiwan

This study is to determine the concentrations of Hg, Zn , Cu , Ni , Pb and Cd in Galeus sauteri in the waters off northeastern Taiwan by flameless and flame atomic absorption spectrophotometry. The concentration of Zn was found to be abundant in vertebrae (72.29ºg.g-1  dry.wt.) and stomach (71.85ºg.g-1  dry wt.) samples and was the lowest in muscle samples (17.00ºg.g-1 dry wt.). The concentration of Cu was associated with stomach samples (9.23ºg.g-1 dry wt.) and the highest concentrations of Cd was found in liver (0.99ºg.g-1  dry wt.) and kidney (1.13ºg.g-1 dry wt.) samples. The concentrations of Pb (ˇ0.02ºg.g-1  dry wt.) and Ni (ˇ0.01ºg.g-1  dry wt.) were not detectable and that of Hg was found abundant in liver (293.60 ng.g -1  wet wt.) and muscle (871.42 ng.g-1  wet wt.) samples. The Zn ranked the first place in concentration series of G. sauteri and followed by Cu. There was no significant difference on heavy metal levels between males and females except that of Zn in gonad and Cu in kidney. The concentrations of Zn and Cu in liver and vertebrae have significantly temporal variation. There was no significantly temporal variation on Cd and Hg which were not essential elements. Hence, concentrations of Cd and Hg could be resulted from biomagnification and long-term accumulation. There was an exponential positive relationship between the length of adult  G.sauteri and Hg concentration in the muscle.The concentration of Hg in elesmobranchs was higher than that in teleosts, but no significant difference on the concentrations of Zn was found between  G. Sauteri  and teleosts. 


*Chiaramonte, Gustavo E., Tamini, Leandro L., Perez, Jorge E., Cappozzo, H. Luis

Museo Argentino de Ciencias Naturales, Estacióñ Hidrobiológica de Puerto Quequén (EHPQ), Buenos Aires 1405 Argentina

Preliminary study of discard composition of Batoids in a bottom trawl fishery at Puerto Quequéñ, Buenos Aires, Argentina.

From the 439 coastal vessels working in Argentina, 25 are at Puerto Quequéñ(38 37' S, 58 50' W). Bottom trawl (BT), in multispecific fishery, is the most common kind of gear used and the fishing discard is composed by invertebrates, elasmobranchs and finfishes. This work describes the by-catch composition of batoids in BT at Puerto Quequéñ, studied during 1998 winter-spring seasons by on board observed in 24 gear operations. Eleven batoid species were recognized and 599 specimens were weighted and measured disc width. The commercial species were  Raja castelnaui,  R. flavirostris  and  R. cyclophora  . Vessels worked in the same fishing area during winter and spring and each gear operation spent 2.2 Ò 0.3 hours. Batoids was 56 % of the total catch with an average of 220.13 Ò 156.80 kg per operation (83.6 Ò 60.5 kg of commercial biomass) in winter and 309.22 Ò 201.99 kg (56.9 Ò 39.1 kg) in spring. Batoids was 57.2% of the discard in winter and 72% in spring. Electric ray,  Discopyge stchudii, was 78,5% of the race captured (sex ratio 1:0.9; mature males and females 87 and 90%) and all the individuals were discarded . For the electric ray populations and other diferent taxa, BT fishery impact might by important and its effect on benthonic communities has not been measured yet. 


*Correia, Joáo, Figueiredo, Ivone, Silva, Alexandre

(JC) Esplanada D. Carlos I, Oceanário de Lisboa, Lisboa, 1998 Portugal; (IF) Av. Brasília, DRM, IPIMAR, Lisboa, 1400 Portugal; (AS), DOP, Universidade dos Açores, Horta, 9900 Portugal

Age and growth of Blackmouth Catsharks,  Galeus melastomus, from Portuguese waters

1301 vertebrae were extracted from Blackmouth catsharks fished off the Portuguese Continental slope during five surveys held by the IPIMAR in 1994 and 1995. The vertebrae were prepared and observed following a protocol established earlier by the same authors. A growth curve was established based on vertebrae where both readers had 100% agreement (56%) and parameters were estimated using models from Von Bertallanfy, Gompertz, Richards and Schnute. The model that provided the best fit for the data was Richards', yielding Linf = 70.0 cm, K = 0.57, T0 = 2.27. These results were verified using MULTIFAN, a length frequency analysis based on five length distributions totalling 10.361 individuals. 


Cortés, Enric

NOAA/NMFS, Panama City, FL 32408

Life history patterns and relationships in sharks

This study examines life history patterns and correlations between traits related to body size, reproduction, age, and growth in sharks, using data from over 200 populations. Interspecifically, body size correlated positively with litter size and offspring size, and a trade-off between litter size and offspring size was found after factoring out the effects of body size. Offspring size correlated positively with growth completion rate (K) after correcting for body size effects. Parental size for males, females, and genders combined was negatively correlated with K. Parental size and size at maturity exhibited a strong positive correlation, with sexual maturity occurring at about 75% of maximum size in both genders. Males were found to be 9% smaller than females and to reach their maximum length 46% faster than females on average. Maximum size and longevity were not correlated in females, but were positively correlated in males. Principal component and cluster analyses were used to reflect similarities among traits of 40 populations and three separate life history strategies were identified. Among conspecifics, body size shows considerable geographic variability, but no clear patterns could be discerned. There is also limited evidence of clinal variation in life history traits in some species. 


Didier, Dominique A.

The Academy of Natural Sciences, Philadelphia, PA 19103

Diversity and taxonomy of chimaeroid fishes (Chondrichthyes, Chimaeridae)

At present there are 34 described species of chimaeroid fishes. Taxonomy of this lineage is historically problematic and many species of chimaeroids remain undetermined due to lack of useful characters for species identification. As part of a taxonomic revision of chimaeroid fishes over 1200 specimens were examined. A total of 35 measurements were taken on each specimen for morphometric analysis. At least 5 described species of chimaeroids are synonymous, 4 new species have been described, and at least 9 additional new species have been discovered. Status of each species, including several newly described species, and known geographic range, including range extensions for some species are presented. Characters for species determination and phylogenetic analysis are identified. Accurate identification of species is critical for management and preservation of chimaeroids as a bycatch and emerging fishery. This study emphasizes the instrumental role of systematics research centers, such as museums, as leaders in addressing issues of global biodiversity and conservation. Supported by NSF DEB-9510735. 


*Ellis, Jim, Rogers, Stuart

Lowestoft Laboratory, Centre for the Environment, Lowestoft, Suffolk NR33 0HT U.K.

Nursery areas of elasmobranch fishes in the coastal waters of the British Isles

Nursery areas are utilised by many species of elasmobranch fishes and are important habitats for neonatal and juvenile individuals. Nursery areas of coastal elamobranchs are typically in shallower waters than areas inhabited by the adults, and usually provide abundant food resources and protection from predation. Nursery areas have been documented for several species of carcharhinid and sphyrnid sharks, although there have been fewer studies on the nursery grounds of other families. Additionally, there are few records of elasmobranch nursery grounds in the coastal waters of the British Isles. Groundfish survey data (1988-1998) from the English Channel, Irish Sea and Bristol Channel were used to identify those locations where juvenile demersal elasmobranchs and the egg cases of oviparous species (e.g.  Raja  spp. and  Scyliorhinus canicula ) occur. Recent data on the macro-epibenthic assemblages within the study areas are used to describe some of the biological characteristics of these juvenile habitats. 


*Feldheim, Kevin A., Gruber, Samuel H., Ashley, Mary V.

(KAF) Dept. of Biological Sciences, University of Illinois at Chicago/Bimini Biological Field Station, Chicago, IL 60607; (SHG) Division of Marine Biology and Fisheries, Bimini Biological Field Station/University of Miami, Miami, FL 33194; (MVA) Dept. of Biological Sciences (M/C 066), University of Illinois at Chicago, Chicago, IL 60607

Multiple paternity of a lemon shark litter determined by DNA microsatellite analysis

A long term field and genetic study of lemon shark mating system and breeding biology is in progress at a nursery ground in Bimini, Bahamas. In the spring of 1996 an adult female lemon shark was caught, measured, sampled for DNA analysis, and injected with a PIT tag. The female was judged to be pregnant when caught. This same female was also caught in April, 1998. At the time of her second capture, the female gave birth to 13 offspring, of which 11 were caught, tagged, and sampled. The recapture of this female provides the first definitive evidence that female lemon sharks are returning to give birth at the Bimini nursery ground, and the reproductive cycle can be no longer than biennial for some females. We used four microsatellite marker loci, developed from a genomic library of  Negaprion brevirostris, to genotype the adult female and her litter. At two of the four loci, four paternal alleles were observed among the pups, indicating that the littermates were sired by at least two males. These results suggest that lemon sharks likely have a polygamous mating system. Observation and analysis of this single female therefore provided critical new information regarding the mating and reproduction of a large coastal shark. 


*Feldheim, Kevin A., Gruber, Samuel H., Ashley, Mary V.

(KAF) Dept. of Biological Sciences, University of Illinois at Chicago/Bimini Biological Field Station, Chicago, IL 60607 U.S.A; (SHG) Division of Marine Biology and Fisheries, Bimini Biological Field Station/University of Miami, Miami, FL 33194; (MVA) Dept. of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607

Isolation and characterization of microsatellite markers in the lemon shark genome

Although microsatellite loci have proven to be extremely useful for population genetic studies of many vertebrates, their application in elasmobranchs has been extremely limited. We are currently developing microsatellite markers for lemon sharks ( Negaprion brevirostris ) in order to assess the local mating system and larger-scale stock structure of this species. A size selected plasmid library was constructed from genomic DNA and screened for 10 di- and trinucleotide repeats. Screening yielded 42 positive clones, of which 35 have been sequenced. (CA) and (GA) dinucleotide repeats were primarily found. Primer pairs were developed for 21 loci, and these are being screened. To date, only five loci have been shown to be polymorphic, suggesting that microsatellite loci in sharks may be less variable than in other vertebrates. Two loci, LS22 and LS30, have been optimized, and at least 90 adult and juvenile lemon sharks from two populations, Bimini, Bahamas, and Marquesas Key, Florida have been genotyped at each locus. LS22 has 16 alleles and observed heterozygosity of 0.82 and LS30 has 15 alleles and observed heterozygosity of 0.70. These preliminary data suggest that although application of microsatellite markers in elasmobranchs may require additional screening, these markers can provide an important new tool for shark biologists. 


*Fluharty, Cynthia A., Grogan, Eileen D.

Saint Joseph's University, Philadelphia, PA 19131

Chondrichthyan calcified cartilage: chimaerid cranial tissue with reference to Squalus.

Select cartilages of the chimaerid,  Callorhinchus capensis, were processed for light microscopy, stained with hematoxylin and eosin, alizarin red, and von Kossa stains, and assessed for features of mineralization. The calcified cartilage demonstrates a tesserate-mode of mineralization which is fundamentally similar to that observed for  Squalus acanthias . Calcification exists in the form of superficial, polygonal deposits of calcium phosphate. In cross section, they appear block-like and are located subperichondrally. Viable chondrocytes and Liesegang waves could be seen throughout the bodies of calcification. Comparison of select stains permits a study of progressive mineralization. Presumptive sites of mineralization first stain positive with alizarin red then positive with von Kossa. This suggests the progression from calcium to calcium phosphate as mineralization proceeds. Fundamentally these results conform to those obtained from examination of  S. acanthias . They demonstrate similar developmental and histological characteristics of mineralization in sister taxa. However, there was no evidence of a discrete tessera cap, as has been noted in  Squalus  and other sharks and jaw tissue provided evidence of mineralization other than that found peripherally. Regional variation in the stage of mineralization was observed across the tissue. At this time these features are interpreted as architectural and stress related.