Helminth assemblages of the turtle Emydura macquarii (Pleurodira: Chelidae) Queensland, Australia

The helminth fauna of 76 Emydura macquarii from 3 river systems in central and northern Queensland was examined. Eleven species were found, including 2 nematodes, 6 trematodes, 1 aspidogastrean, 1 cestode, and 1 monogenean. Analysis of helminth diversity showed that the Fitzroy and Ross River turtles had communities of comparable diversity, but the helminth communities in Proserpine River turtles were much less diverse. The helminth communities in all localities were dominated by trematodes. Polystomoides australiensis was the most prevalent, being found in 60% of the Ross River turtles, 57% of the Fitzroy River turtles, and 46% of the Proserpine River turtles. Notopronocephalus peekayi was the most abundant species, with mean abundances of 5.9 in the Ross River turtles and 9.8 in the Fitzroy River turtles. Species richness, Simpson's Reciprocal Index, was highest, 4.68, for the Ross River helminth community, Sorensen's Qualitative Index showed 95% similarity between the Ross River and Fitzroy River communities, although Sorensen's Quantitative Index indicated only 35% similarity between the 2 sites. Host feeding patterns are likely the most important factor affecting species richness of the helminth infracommunities, as the majority of helminth species are transmitted by food-web interactions involving intermediate hosts.     

Morphology and function of the feeding apparatus of Pelusios castaneus (Chelonia; Pleurodira)

Feeding mechanics of vertebrates depend on physical constraints of the surrounding media, water or air. Such functions are inseparably combined with form. The aim of this study is to show this linkage for the pleurodiran freshwater turtle Pelusios castaneus and, additionally, to point out the major functional and biomechanical distinctions between aquatic and terrestrial feeding turtles as well as several intermediate forms. Gross morphological investigations of skull, hyoid, tongue, and connected musculature, as well as scanning electron microscopy of the tongue surface, show typical features of an aquatic feeder, e.g., strongly developed hyoid apparatus vs. a small tongue with only moderate papillae, and massive jaw and hyoid musculature. Additionally, the special function of the esophagus during feeding is investigated to elucidate the problems of a bidirectional feeder. The esophagus is highly distensible in order to store the excess water sucked in during feeding until the prey is fixed by the jaws. The distension is probably achieved by a coincidence of active (branchial horn) as well as passive (water) components. P. castaneus is a feeding generalist, and is well adapted to the aquatic medium in terms of its functional as well as morphological features.     

The primary structure of myoglobin from pacific green sea turtle (Chelonia mydas caranigra)

The amino acid sequence of the main component myoglobin from skeletal muscle of Pacific green sea turtle (Chelonia mydas caranigra) has been determined. The globin is 153 residues in length and has a free amino-terminus. The heme-binding and internal residues are as found in mammalian myoglobins. Ten substitutions are observed between this myoglobin and that from map turtle. About 38, 52, 47 and 86 substitutions are noted in comparison with the myoglobins of other reptiles, mammals, birds and fish, respectively. The inferred pattern of structural stabilization and conservation of two loci are typical of tetrapod myoglobin.     

Nematode parasites of the turtle Pelusios sinuatus (pelomedusidae: Pleurodira) from southern Africa

Summary Two nematode parasites are described from the turtle Pelusios sinuatus of southern Africa. Camallanus chelonius n. sp. (Camallanoidae) is easily distinguished from other species reported from Africa in possessing less than 10 smooth ridges in the buccal valves. It most closely resembles a group of seven species described from Indian amphibians but may be differentiated from these by a combination of characters: shape of the female tail and distal end of the spicules, male caudal papillae, presence or absence of small barbs between the bases of the buccal valve ridges. C. chelonius is intermediate in cephalic morphology between other Camallanus spp., which are all restricted to fish and amphibian hosts, and the genus Serpinema reported only in turtles. Falcaustra pelusios n.sp. (Cosmocercoidea) is the first species of the genus reported in pelomedusid turtles. It is easily distinguished from all other species by the presence of two large and complex cheilostomal rings in the cephalic end, a very short male tail, large gubernaculum, relatively short thick spicules and large number (more than 50 pairs) of subventral preanal muscle cells posterior to the sucker. ac]19810907     

Reproduction of the Australian freshwater turtle Emydura krefftii (Chelonia: Chelidae)

A study of the reproduction of Krefft's river tortoise, Emydura krefftii , was conducted in the perched dune lakes of Fraser Island, Queensland. Mature male specimens exhibit a postnuptial pattern of spermatogenesis typical of temperate-zone turtles elsewhere, with a peak in spermatogenic activity in autumn and a cessation of activity during the breeding season in spring and early summer. The spermatogenic cycle is paralleled by seasonal variation in testicular weight (standardized for body size) and in the diameter of the seminiferous tubules. Sperm are abundant in the epididymal canals throughout the year. Mating was observed in autumn, late winter and spring.
Females have a cyclic reproductive pattern, with distinct phases of follicular enlargement, ovulation and oviducal period, and quiescence. Yolk begins to accumulate in the ovaries in late summer, and the accumulation continues unabated through the winter, presumably by the transfer of material from fat stores to the ovaries. Ovulations occur from late winter to mid-summer. Atresia of follicles that fail to ovulate was demonstrated histologically.
Emydura krefftii lay up to three clutches of hard-shelled ellipsoid eggs per season. Each clutch contains between four and 10 eggs; the number is strongly correlated with maternal body size. Reproductive potential ranges from 12 eggs per annum for a female that has recently matured (carapace length c. 150 mm), to 30 eggs per annum for a full-sized female (length c. 250 mm). Selected life-history traits of Emydura krefftii are discussed in the context of findings for other populations of the species and for other species of freshwater turtle.     

The Green sea turtle (Chelonia mydas): mating, nesting and hatching on a farm

The collection of eggs from wild rookeries for incubation and hatching on the Mariculture Ltd farm on Grand Cayman Island, BWI, was described in the previous paper. It was realized, however, that this method of stocking the farm must sooner or later be superseded by the production of farm-laid eggs, and at an early stage a start was made on the task of establishing a breeding colony. The necessary collection of adult turtles and progress in breeding to the end of 1973 is described in the present paper.     

The primary structures of gundi (Ctenodactylus gundi, Rodentia) hemoglobin and myoglobin

The primary structures of the alpha- and beta-chains of hemoglobin and myoglobin from the gundi (Ctenodactylus gundi, Rodentia) are presented. The sequences were determined after enzymatic and chemical cleavages of the polypeptide chains and by sequencing of the peptides mainly by automated sequence analysis. The sequences of gundi hemoglobin chains and of myoglobin are compared with those of other rodents.     

Oviducal development in a Krefft's river turtle,Emydura krefftii gray (Chelonia: Chelidae)

A clutch of Emydura krefftii eggs hatched 20 days after oviposition, in contrast to the normal incubation period of 45–50 days for this species. This shortened incubation and the presence of stage 20–21 embryos at oviposition indicates facultative oviducal development in E krefftii.     

Characterization of polymorphic microsatellite markers for the green turtle (Chelonia mydas)

We describe primers and polymerase chain reaction conditions to amplify 12 microsatellite loci from the green turtle (Chelonia mydas), including one dinucleotide, four trinucleotide and seven tetranucleotide loci. The primers were tested on 78 individuals from a Pacific population nesting in the Hawaiian Islands. The primer pairs developed in this study yielded an average of 8.33 alleles per locus (range of 3-15 alleles), an average observed heterozygosity of 0.668 (range 0.309-0.910), and an average polymorphic information content of 0.647 (range 0.287-0.894).     

The Green sea turtle (Chelonia mydas): further observations on breeding in captivity

Mating, nesting and hatching of the Green sea turtle on Mariculture Ltd's farm on Grand Cayman Island, BWI in 1973 were recorded in a previous paper. The results described were the first of their kind, so that events in the farm breeding colony in the following year were awaited with much interest, especially as to hatchability of the eggs. The observations made in 1974, which extended and mainly confirmed those made in 1973, are described below.     

Two new species of Choanocotyle Jue Sue and Platt, 1998 (Digenea: Choanocotylidae) from an Australian freshwater turtle (Testudines: Pleurodira: Chelidae)

Choanocotyle hobbsi n. sp. and Choanocotyle juesuei n. sp. are described from the small intestine of the oblong turtle Chelodina oblonga from the vicinity of Perth, Western Australia. These are the third and fourth species referred to Choanocotyle. Choanocotyle hobbsi is most similar to Choanocotyle nematoides but differs in the size and shape of the oral sucker and the absence of a median loop in the cirrus sac. Choanocotyle juesuei is most similar to Choanocotyle elegans but differs in the size of the oral sucker and other morphometric criteria. Comparative analysis of the sequences of different nuclear ribosomal deoxyribonucleic acid regions of C. nematoides and C. hobbsi has confirmed that they are closely related but distinct species.     

The Green sea turtle (Chelonia mydas): nesting on Ascension Island, 1973–1974

The collection of eggs of Chelonia mydas from beaches on Ascension Island and elsewhere for hatching at the Mariculture Ltd farm on Grand Cayman was described in a previous paper (Simon, 1975). Improved organization of these collections has made it possible to record many incidental observations which throw light on the nesting behaviour and performance of the female Chelonia , and Ascension Island, because of its small size, numerous beaches and good communications, proved to be particularly favourable for such research. The present paper records observations made in February and March 1973 and 1974. The second author has contributed only by the analysis of the data and the preparation of the paper.     

Conformational changes of alpha-macroglobulin and ovomacroglobulin from the green turtle (Chelonia mydas japonica)

Green turtle plasma alpha-macroglobulin and ovomacroglobulin underwent conformational changes when they were treated with proteinases or methylamine. Their conformational changes were studied by HPLC gel chromatography, circular dichroism, and electron microscopy. The Stokes radii of native green turtle alpha-macroglobulin and ovomacroglobulin were estimated to be 84.3 +/- 0.5 A, and 93.0 +/- 0.5 A, respectively, by means of an HPLC experiment. After reaction with methylamine or proteinases, the Stokes radius of alpha-macroglobulin changed to 83.0 +/- 0.5 A or 85.4 +/- 0.5 A, respectively, and that of ovomacroglobulin to 93.0 +/- 0.5 A or 87.1 +/- 0.5 A. The circular dichroic spectra of native alpha-macroglobulin and ovomacroglobulin exhibited a negative band at around 215 nm, indicating the presence of beta-structure. Reaction of the two macroglobulins with methylamine resulted in a slight decrease in the ellipticity and reaction with proteinases led to a slight increase. The electron micrographic images of native alpha-macroglobulin and ovomacroglobulin can be described as deformed rings for the former and rugby balls for the latter. A common characteristic feature of the two molecules was that the central parts of the molecules were only thinly occupied by subunit. After reaction of macroglobulins with proteinases, the void spaces became partially filled and their overall shape more rectangular. Methylamine treatment caused a structural change only in alpha-macroglobulin but not in ovomacroglobulin. The difference in the susceptibility of the macroglobulins to methylamine was taken as an indication of evolutional divergence of the two homologous proteins within the last 300 million years.     

Hb(alphaalpha,betabeta): a novel fusion construct for a dimeric, four-domain hemoglobin

Hemoglobin-based blood substitutes are one of the options available to derive a resuscitating fluid taking into account clinical and physiological demands. In this paper we investigated a novel protein, Hb(alphaalpha,betabeta) obtained as a combination of two homodimers alpha(2) and beta(2) both derived from a fusion gene containing two alfa chains or two beta chains, each respectively coupled via a specific linker. The construct here described is thus a novel heterodimeric hemoglobin carrying four heme groups. The protein cannot dissociate into dimers, as demonstrated by its absence of reactivity versus haptoglobin, and is expected to have a relatively long circulating half-life. The modification does not increase the autoxidation rate, but increases the oxygen affinity, due to a destabilization of the T quaternary state. Characterization of the biochemical properties of this protein in comparison with HbA is reported.     

Structural analysis of the minor human hemoglobin components: Hb AIa1, Hb AIa2 and Hb AIb

Human hemolysate contains several minor hemoglobin components, including Hb AIa1, Hb AIa2, Hb AIb and Hb AIc which are post-translational modifications of the major component, Hb A0. Hb AIc is known to contain glucose attached to the N terminus of the beta chains by a ketoamine linkage. We separated the alpha and beta globin chains from purified Hb AIa1, Hb AIa2 and Hb AIb by ion-exchange chromatography. The beta chains were reducible by sodium borohydride and gave a positive thiobarbituric acid test. These results indicated that they are modified by ketoamine-linked carbohydrate. In addition, phosphate analysis revealed 1.5 phosphate residue associated with each beta AIa1 chain and 1 phosphate residue with each beta AIa2 chain. Hb AIa1, Hb AIa2 and Hb AIb were all found to be contaminated by non-globin proteins. Protein-sequencing approaches demonstrated that the N termini of beta AIa1, beta AIa2 and beta AIb were blocked. In support of this conclusion, analysis of tryptic digests of beta AIa2 and B AIb revealed modified N-terminal peptides. We conclude that, like Hb AIc, components Hb AIa1, Hb AIa2 and Hb AIb also contain a sugar moiety linked to the N terminus of the beta chain.     

Patterns of lipid storage and mobilisation in the female green sea turtle ( Chelonia mydas)

Reproductive data from southern Queensland indicate that vitellogenesis in female Chelonia mydas takes approximately 8 months and is followed by a migration to a breeding area. At Heron Island, females lay multiple clutches over approximately 3 months. To investigate how females mobilise and store lipid during the breeding season we collected plasma, yolk, and fat tissue samples from females at a variety of stages during the nesting season. In breeding females, concentrations of plasma triglyceride increased seasonally. They reached peak concentrations during vitellogenesis and courtship, remained high throughout the nesting season, and then declined to a nadir after the last clutch. Plasma protein concentration increased throughout the breeding season, peaking following the last clutch for the season. Yolk lipids were highest during courtship and were similar throughout the nesting season, suggesting that uptake of lipid by ovarian follicles is completed prior to the beginning of the nesting season. Plasma triglyceride decreases in females with prolonged periods of unsuccessful nesting, and total lipid levels in adipose tissue and follicle yolks were significantly lower in atretic females. It appears that: (1) endogenous energy reserves can be reduced by stochastic environmental events (such as those reducing nesting success), and (2) a metabolic shift signalling the end of the nesting season is characterised by a drop in plasma triglycerides and slight increase in total plasma protein.     

Mitochondrial DNA diversity and phylogeography of endangered green turtle (Chelonia mydas) populations in Africa

We analysed the genetic structure of seven nesting sites of the endangered green turtle (Chelonia mydas) in Africa using mitochondrial DNA control region sequences. Tissue samples were collected from 188 nesting females at six sites in West Africa and one in the Indian Ocean. A 488 bp fragment of the control region revealed 14 different haplotypes, 10 of which are previously undescribed. The most common haplotype (CM8) was observed in 157 individuals. All other haplotypes were closely related, except two divergent lineages: CM38, removed by four substitutions, and the three Indian Ocean haplotypes, distinguished by 31 substitutions. Significant differences in haplotype and nucleotide diversity were observed between Atlantic rookeries and among ocean basins. Analysis of molecular variance revealed high levels of differentiation between the Atlantic and the Indian Ocean populations but a much shallower Atlantic substructuring. Green turtle population genetic structure is thought to have been shaped by a dynamic succession of extinction and recolonisation of rookeries, by natal homing and occasional breakdown in nest-site fidelity. Mismatch distributions of pairwise differences between haplotypes at each rookery were found to be consistent with recent population expansion. We argue that demographic histories can be explained by scenarios at several temporal scales, including geological events, sea level fluctuations and more recent patterns of exploitation. We discuss management and conservation implications of our results for these threatened populations, identifying two ESUs (one in the Atlantic and one in the Indian ocean) and three MUs within the Atlantic.     

Aptorchis glandularis n. sp. (Digenea: Plagiorchioidea) from the northwestern red-faced turtle, Emydura australis, (Pleurodira: Chelidae) in the Kimberley, Western Australia

Aptorchis glandularis n. sp. is described from the intestine of the northwestern red-faced turtle, Emydura australis (Pleurodira: Chelidae), in the Kimberley, Western Australia. This digenean is morphologically most similar to Aptorchis aequalis but can be differentiated readily from the latter species by the presence of ventral glands arranged in 3 rows. This feature is unique among plagiorhioidean digeneans and resembles the glands observed in some monostome digeneans in Notocotylidae and Microscaphidiidae. Comparison of approximately 2,600 bases of ribosomal DNA (partial 18S, complete ITS1+5.8S+ITS2, partial 28S), obtained from all 5 known Aptorchis species, strongly supports the status of Aptorchis glandularis n. sp. as a new species. Phylogenetic analysis of these sequence data demonstrates 2 strongly supported clades (A. pearsoni + A. megacetabulus) and (A. aequalis + A. glandularis n. sp.), with A. megapharynx representing a separate lineage. This is the first report of an endoparasite from Emydura australis.