A NEW SPECIES OF MYXOBOLUS (CNIDARIA: MYXOSPOREA: MYXOBOLIDAE) FROM THE GILLS OF CREEK CHUB, SEMOTILUS ATROMACULATUS (CYPRINIFORMES: LEUCISCIDAE: PLAGIOPTERINAE), FROM THE OUACHITA DRAINAGE OF ARKANSAS

During October and November 2021, 33 creek chubs, Semotilus atromaculatus, were collected from 3 sites in Polk County, Arkansas (Ouachita River drainage), and their gills, gallbladder, fins, integument, musculature, and other major organs were examined for myxozoans. The gills of 9 (27%) were infected with a new myxozoan, Myxobolus fountainae n. sp. Qualitative and quantitative morphological data were from fresh and formalin-fixed preserved spores, while molecular data consisted of a 1918 base pair sequence of the partial small subunit ribosomal RNA gene. Phylogenetic analysis grouped M. fountainae n. sp. with the other leuciscid-infecting myxobolids from North America and within a larger clade of European myxozoans. In addition, histological information is provided on the infection. A previous record of Myxobolus muelleriBütschli, 1882, from the gills and ureters of S. atromaculatus is considered invalid and represents an unknown species. Myxobolus fountainae n. sp. is the only named myxozoan known to infect the gill filaments of S. atromaculatus, whereas Myxobolus pendula (Guilford, 1967) infects the gill arches.

A New Isospora (Apicomplexa: Eimeriidae) from the Carolina Wren, Thryothorus ludovicianus ludovicianus (Passeriformes: Certhioidea: Troglodytidae), in Southeastern Oklahoma, USA

PURPOSE

Nothing is known of the coccidian parasites of the Carolina wren, Thryothorus ludovicianus ludovicianus (Latham, 1790). Here, we report a new species of Isospora from T. l. ludovicianus from Oklahoma, USA.

METHODS

Faecal samples were collected between September and December 2021 from five adult T. l. ludovicianus taken with a mist net from McCurtain County, Oklahoma, USA, and examined for coccidian parasites. Samples were placed in individual vials containing aqueous potassium dichromate. They were examined for coccidia after flotation in Sheather's sugar solution, measured, and photographed. Tissue samples from the intestine of a single positive bird were removed and placed in 10% neutral-buffered formalin for examination of coccidian endogenous stages.

RESULTS

A single Carolina wren (20%) was found to be passing a new species of Isospora. Oocysts of Isospora edwardwilsoni n. sp. were subspheroidal to ovoidal with a smooth bi-layered wall, measured (L × W) 23.8 × 20.3 µm, and had a length/width (L/W) ratio of 1.2; a micropyle and oocyst residuum was absent but typically one to up to four polar granule(s) was present. Sporocysts are ovoidal to ellipsoidal and measured 15.3 × 9.7 µm, L/W 1.6; a knob-like Stieda body was present as well as a distinct rounded sub-Stieda body. The sporocyst residuum was composed of various-sized granules in a compact irregular mass or dispersed between and across the sporozoite, or a combination of both within the same sporocyst. Information is also presented on the endogenous development of this coccidian.

CONCLUSION

This is the first coccidian reported from T. l. ludovicianus and, more importantly, the first known from the members of the family Troglodytidae in North America.

No remnants of nasolacrimal ducts in any Desmognathini salamanders indicates loss early in their evolutionary history

Previous studies demonstrated that nasolacrimal ducts were present in the ancestral plethodontid lineage. Two lineages within Plethodontidae contain individuals that do not possess nasolacrimal ducts: Desmognathus and Eurycea. Earlier works examined only two species of Desmognathus, D. fuscus and D. monticola. We obtained every Desmognathini (Phaeognathus + Desmognathus) species possible from novel collections and museum collections and assessed presence or absence of nasolacrimal ducts using contrast-enhanced computed tomography and routine histological procedures. The goal was to test the hypothesis that nasolacrimal ducts were lost on the evolutionary branch leading to Desmognathus. We rejected our hypothesis by finding that nasolacrimal ducts were absent in all Desmognathus that we examined and Phaeognathus hubrichti; thus, we recovered the absence of nasolacrimal ducts on the evolutionary branch leading to Desmognathini.

Histology of the Urogenital System in the American Bullfrog (Rana catesbeiana), with Emphasis on Male Reproductive Morphology

Previous studies have revealed variations in the urogenital system morphology of amphibians. Recently, the urogenital system of salamanders was reviewed and terminology was synonymized across taxa. Discrepancies exist in the terminology describing the urogenital system of anurans, which prompted our group to develop a complete, detailed description of the urogenital system in an anuran species and provide nomenclature that is synonymous with those of other amphibian taxa. In Rana catesbeiana, sperm mature within spermatocysts of the seminiferous tubule epithelia and are transported to a series of intratesticular ducts that exit the testes and merge to form vasa efferentia. Vasa efferentia converge into single longitudinal ducts (Bidder's ducts) on the lateral aspects of the kidneys. Branches from the longitudinal ducts merge with genital kidney renal tubules through renal corpuscles. The nephrons travel caudally and empty into the Wöffian ducts. Similar to salamanders, the caudal portion of the kidneys (termed the pelvic kidneys in salamanders) only possesses nephrons involved in urine formation, not sperm transport. Data from the present study provide a detailed description and synonymous nomenclature that can be used to make future comparative analyses between taxa more efficient.

Metals, Parasites, and Environmental Conditions Affecting Breeding Populations of Spotted Salamanders (Ambystoma maculatum) in Northern Arkansas, USA

The spotted salamander (Ambystoma maculatum) is indigenous to northern Arkansas, and several breeding sites are known to exist in the region. Spotted salamanders (n = 17) were collected and examined for parasites and only three females harbored nematodes (Physaloptera spp.). Chronic aquatic bioassays were conducted using water collected from eight breeding ponds during different hydroperiod events. No lethal or sublethal effects were measured in Ceriodaphnia dubia; however, decreased growth and survival were seen in Pimephales promelas. Aqueous, sediment, and salamander hepatic samples were analyzed for As, Cd, Cu, Pb, and Ni. Metal analysis revealed possible increased metal exposure following precipitation, with greatest metal concentrations measured in sediment samples. Hepatic metal concentrations were similar in parasitized and non-parasitized individuals, and greatest Pb concentrations were measured following normal precipitation events. Determining environmental stressors of amphibians, especially during their breeding and subsequent larval life stage, is imperative to improve species conservation.

Spermatogenic cycle of a plethodontid salamander, Eurycea longicauda (Amphibia, Urodela)

Previous investigators have described the spermatogenic cycles of numerous species of plethodontid salamanders. Most studies describe a fairly stereotypical cycle with meiotic divisions of spermatogenesis commencing in the spring/summer. However, many studies lack details obtainable from histological examination and/or testicular squashes and, instead, provide only mensural data from the testes. Studies that lacked microscopic evaluation often revealed spermatogenic cycles that varied greatly from that of the stereotypical cycle with meiotic divisions commencing in the fall/winter. Those studies hamper comparisons between the spermatogenic cycles of different species and their environments, as they do not provide a correlation between testicular size and any aspect of the spermatogenic cycle. In the following manuscript, we elucidate the spermatogenic cycle of Eurycea longicauda longicauda in an effort to outline an appropriate protocol for analyzing spermatogenesis in salamanders that will facilitate future comparative studies. Like many Nearctic plethodontids, E. l. longicauda exhibits a meiotic wave that travels through the testes during the summer; this process is followed by spermiogenesis, spermiation, and recrudescence in the fall, winter, and spring.

Testicular histology and germ cell cytology during spermatogenesis in the Mississippi map turtle, Graptemys pseudogeographica kohnii, from Northeast Arkansas

The testicular histology and cytology of spermatogenesis in Graptemys pseudogeographica kohnii were examined using specimens collected between July 1996 and May 2004 from counties in northeastern Arkansas. A histological examination of the testes and germ cell cytology indicates a postnuptial testicular cycle of spermatogenesis and a major fall spermiation event. The majority of the germ cell populations in May and June specimens are represented by resting spermatogonia, type A spermatogonia, type B spermatogonia, pre-leptotene spermatocytes, and numerous Sertoli cell nuclei near the basement membrane. The start of proliferation is evident as spermatogonia in metaphase are present near the basal lamina and many of these germ cells have entered meiosis in June seminiferous tubules. Major spermatogenic events occur in the June and July specimens and result in an increased height of the seminiferous epithelium and increased diameter of the seminiferous tubules. The germ cell population during this time is represented by spermatogonia (type A, B, and resting), hypertrophic cells, large populations of early primary spermatocytes, and early round spermatids. By September, the major germ cell population has progressed past meiosis with abundant round and early elongating spermatids dominating the seminiferous epithelium. October seminiferous epithelia are marked by a decreas in height and mature spermatozoa fill the luminal space. Round and elongating spermatids constitute the largest portion of the germ cell population. Following the spermiation event, the testes enter a period of quiescence that lasts till the next spermatogenic cycle, which begins in the subsequent spring. Based on the cytological development of the seminiferous tubules revealed by our study, Graptemys pseudogeographica kohnii demonstrates a temporal germ cell development strategy similar to other temperate reptiles. A single major generation of germ cells progresses through spermatogenesis each year resulting in a single spermiation event with sperm stored within the epididymis until the next spring mating season.

A New Species of Eimeria (Apicomplexa: Eimeriidae) from Green Frog, Lithobates clamitans (Anura: Ranidae) from Arkansas, U.S.A

Between April and October 2012, 20 juvenile and adult green frogs (Lithobates clamitans) were collected by hand or dipnet from 3 counties of Arkansas and examined for coccidial parasites. A single frog (5%) was found to be passing oocysts of a new eimerian species. Oocysts of Eimeria menaensis n. sp. were ellipsoidal to subspheroidal with a bilayered wall and measured (L × W) 25.4 × 15.6 (23-27 × 13-17) µm, with a L/W ratio of 1.6. A micropyle was absent but an oocyst residuum and polar granule were present. Sporocysts were spheroidal to subspheroidal and measured 5.0 × 5.0 (4-6) µm with L/W of 1.1. An indistinct Stieda body was present, but sub-and para-Stieda bodies were absent. The sporocyst residuum consisted of condensed granules dispersed between sporozoites. Sporozoites were elongate and attenuated at both ends with spheroidal anterior and posterior refractile bodies. This represents the second report of coccidia from L. clamitans and the first time a coccidian has been reported from a green frog from Arkansas.

Two new species of coccidia (Apicomplexa: Eimeriidae) from ground skinks, Scincella lateralis (Sauria: Scincidae), from Arkansas, USA

Between February 2011 and January 2014, 75 ground skinks, Scincella lateralis (Say) were collected from 13 counties of Arkansas and McCurtain County, Oklahoma, USA, and examined for coccidia. Two (3%) and 11 (15%) S. lateralis were found to be passing oöcysts of a new choleoeimerian and isosporan, respectively. Oöcysts of Choleoeimeria ouachitensis n. sp. are ellipsoidal to cylindroidal with a smooth, colourless, bi-layered wall and measure 27.2 × 15.6 μm, and have a length/width (L/W) ratio of 1.7; both micropyle and oöcyst residuum are absent, but 1-2 polar granule(s) are present. Sporocysts are ovoidal, 8.9 × 6.8 μm, L/W 1.3; neither Stieda, sub-Stieda and para-Stieda bodies are present; the walls have two valves joined by longitudinal sutures; a sporocyst residuum consisted of dispersed granules between sporozoites. Oöcysts of Isospora koberi n. sp. are ovoidal with a smooth, colourless, bi-layered wall and measure 25.1 × 20.5 μm, L/W 1.2; both micropyle and oöcyst residuum are absent, but a polar granule is rarely present. Sporocysts are ovoidal, 11.4 × 8.6 μm, L/W 1.3; a nipple-like Stieda body and a sub-Stieda body are present without a para-Stieda body; a sporocyst residuum consisted of condensed granules dispersed between sporozoites. This is the second choleoeimerian and third isosporan reported from S. lateralis.

The testicular sperm ducts and genital kidney of male Ambystoma maculatum (Amphibia, Urodela, Ambystomatidae)

The ducts associated with sperm transport from the testicular lobules to the Wolffian ducts in Ambystoma maculatum were examined with transmission electron microscopy. Based on the ultrastructure and historical precedence, new terminology for this network of ducts is proposed that better represents primary hypotheses of homology. Furthermore, the terminology proposed better characterizes the distinct regions of the sperm transport ducts in salamanders based on anatomy and should, therefore, lead to more accurate comparisons in the future. While developing the above ontology, we also tested the hypothesis that nephrons from the genital kidney are modified from those of the pelvic kidney due to the fact that the former nephrons function in sperm transport. Our ultrastructural analysis of the genital kidney supports this hypothesis, as the basal plasma membrane of distinct functional regions of the nephron (proximal convoluted tubule, distal convoluted tubule, and collecting tubule) appear less folded (indicating decreased surface area and reduced reabsorption efficiency) and the proximal convoluted tubule possesses ciliated epithelial cells along its entire length. Furthermore, visible luminal filtrate is absent from the nephrons of the genital kidney throughout their entire length. Thus, it appears that the nephrons of the genital kidney have reduced reabsorptive capacity and ciliated cells of the proximal convoluted tubule may increase the movement of immature sperm through the sperm transport ducts or aid in the mixing of seminal fluids within the ducts.

Combined Effects of Ephedrine-Containing Dietary Supplements, Caffeine, and Nicotine on Morphology and Ultrastructure of Rat Hearts

Cigarette smokers have an increased risk for coronary artery disease. Nicotine present in cigarettes can adversely affect the cardiovascular system via stimulation of both sympathetic and parasympathetic neurons. Caffeine, another cardiovascular and central nervous system (CNS) stimulant, is commonly found in Ephedra and Ephedra-free dietary supplements. These caffeine-containing supplements also have been linked to cardiovascular toxicities. Although no longer on the U.S market, Ephedra-containing supplements are another source of cardiovascular and CNS stimulants, namely the ephedrine alkaloids. Together caffeine, nicotine, and ephedrine can individually stress the cardiovascular system, and an overlap of these agents is predicted in smokers and dieters. To understand the collective effects of these stimulants on the heart morphology and ultrastructure, rats were exposed to synthetic combinations of nicotine (0.2 mg/kg/day), ephedrine (0-30 mg/kg/day), and/or caffeine (0-24 mg/kg/day) as well as an extract from a caffeine-containing Ephedra supplement (Metabolife 356). After exposure for 3 days, the hearts were removed and examined for hypersensitivity myocarditis and myocardial necrosis. None of the drugs tested alone affected heart tissue morphology, nor were atypical cardiac cells observed. However, in combination, significant interactions were found between caffeine and ephedrine; the interventricular septum was most susceptible, with a significant increase in atypical cardiac cells observed. Nicotine pretreatment caused greater susceptibility to cardiotoxicity associated with combinations of caffeine + ephedrine or Metabolife, particularly in the left ventricle wall. These results indicate that sympathomimetic combinations present in Ephedra supplements may have produced cardiotoxicity reported in consumers of these products. Moreover, the presence of nicotine exacerbates these toxic effects.

The importance of comparative phylogeography in diagnosing introduced species: a lesson from the seal salamander, Desmognathus monticola

BACKGROUND

In most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys. In some cases this challenges our ability to discriminate native from introduced species. This distinction is particularly critical for isolated populations, because relicts of native species may need to be conserved, whereas introduced species may require immediate eradication. Recently an isolated population of seal salamanders, Desmognathus monticola, was discovered on the Ozark Plateau, approximately 700 km west of its broad continuous distribution in the Appalachian Mountains of eastern North America. Using Nested Clade Analysis (NCA) we test whether the Ozark isolate results from population fragmentation (a natural relict) or long distance dispersal (a human-mediated introduction).

RESULTS

Despite its broad distribution in the Appalachian Mountains, the primary haplotype diversity of D. monticola is restricted to less than 2.5% of the distribution in the extreme southern Appalachians, where genetic diversity is high for other co-distributed species. By intensively sampling this genetically diverse region we located haplotypes identical to the Ozark isolate. Nested Clade Analysis supports the hypothesis that the Ozark population was introduced, but it was necessary to include haplotypes that are less than or equal to 0.733% divergent from the Ozark population in order to arrive at this conclusion. These critical haplotypes only occur in < 1.2% of the native distribution and NCA excluding them suggest that the Ozark population is a natural relict.

CONCLUSION

Our analyses suggest that the isolated population of D. monticola from the Ozarks is not native to the region and may need to be extirpated rather than conserved, particularly because of its potential negative impacts on endemic Ozark stream salamander communities. Diagnosing a species as introduced may require locating nearly identical haplotypes in the known native distribution, which may be a major undertaking. Our study demonstrates the importance of considering comparative phylogeographic information for locating critical haplotypes when distinguishing native from introduced species.

A FORTY-THREE YEAR MUSEUM STUDY OF NORTHERN CRICKET FROG (ACRIS CREPITANS) ABNORMALITIES IN ARKANSAS: UPWARD TRENDS AND DISTRIBUTIONS

The northern cricket frog (Acris crepitans) is a resident of streams, rivers, and wetlands of eastern North America. We documented abnormalities in A. crepitans housed in the Arkansas State University Museum of Zoology Herpetology Collection. Abnormality frequency increased from 1957 to 2000 (chi 2 = 43.76, df = 3, P < 0.001). From 1957 through 1979 only 3.33% of specimens were unusual. This rate was 6.87% during the 1990s, and in 2000 it was 8.48%. High frequencies of abnormalities were identified in the following Ozark highland counties: Sharp, Lawrence, and Randolph. We observed 104 abnormalities among 1,464 frogs (7.10%). The differential abnormality frequencies observed between the Arkansas lowlands and highlands are striking. The Ozarks had significantly higher frequencies of abnormalities than other Arkansas regions (chi 2 = 59.76, df = 4, P < 0.001). The Ouachita Mountains had significantly higher frequencies than the Gulf Coastal Plain, Delta, or Arkansas River Valley (chi 2 = 13.172, df = 3, P < 0.01). There was no difference in abnormality frequency between the Gulf Coastal Plain, Delta, and Arkansas River Valley (chi 2 = 0.422, df = 2, P > 0.70). Proposed hypotheses for distributions include: 1) A. crepitans might possess naturally high abnormality levels, and land use practices of the Delta may reduce this variability; 2) an unknown xenobiotic may be in Ozark streams causing increased numbers of abnormalities; 3) the museum's collection effort may be skewed; 4) Delta habitat might be more favorable for green tree frogs (Hyla cinerea) allowing this species to drive out A. crepitans through competition; here, abnormal metamorphs are not detected because they are even less competitive than normal individuals.

A comparative ultrastructural study of spermatozoa of the teiid lizards Cnemidophorus gularis gularis, Cnemidophorus ocellifer, and Kentropyx altamazonica (Reptilia, Squamata, Teiidae)

The ultrastructure of the spermatozoa of Cnemidophorus gularis gularis, Cnemidophorus ocellifer, and Kentropyx altamazonica is described for the first time. Mature spermatozoa of Cnemidophorus spp. and K. altamazonica differ in the occurrence of a perforatorial base plate, the enlargement of axonemal fibers 3 and 8, and shape of mitochondria. The comparisons of the ultrastructure sperm of Cnemidophorus spp. and K. altamazonica with Ameiva ameiva [J. Morphol. (2002) in press] suggest that Ameiva and Cnemidophorus are more similar to each other than either is to Kentropyx. Statistical analyses reveal that sperm of all three species studied are significantly different in the following dimensions: head, acrosome, distal centriole length, and nuclear shoulders width. There was no variable statistically different between the Cnemidophorus spp. only. The length of the tail, midpiece, entire sperm, and nuclear rostrum are significantly different between K. altamazonica and Cnemidophorus spp. Our results indicate that sperm ultrastructure presents intra and intergeneric variability.

Morphology of the spermatozoa of the iguanian lizards Uta stansburiana and Urosaurus ornatus (Squamata, Phrynosomatidae)

The spermatozoa of Uta stansburiana and Urosaurus ornatus show the following squamate autapomorphies: a single perforatorium extending anteriorly from the apical tip of the paracrystalline subacrosomal cone; the presence of an epinuclear electron lucent region; intermitochondrial dense bodies; and the fibrous sheath extending into the midpiece. The acrosome vesicle is flattened and concentrically zoned apically; basally it overlies a subacrosomal cone which invests the nuclear rostrum. A stopper-like perforatorial base plate, rounded nuclear shoulders and a basal nuclear fossa are present. The proximal centriole contains a density within its centre for approximately one half its length and lies at approximately 80 degrees to the distal centriole. The two central singlets of the axoneme extend into the short distal centriole. A peripheral dense fibre is associated with each of the nine triplets of the distal centriole, and the fibre continues posteriorly with each of the nine doublets of the axoneme. A central fibre is associated with the two central singlets. All fibres are absent or vestigial at the level of the annulus. Mitochondria are short sinuous with a maximum of eight seen in transverse section. Uta and Urosaurus sperm differ from each other in their arrangement of intermitochondrial dense bodies in two ways: 1) longitudinally, Uta has five incomplete 'rings' of dense bodies, whereas Urosaurus has only four such rings; 2) in cross section, each individual 'ring' of Uta may contain up to four irregularly spaced dense bodies, whereas Urosaurus contains a maximum of only two dense bodies. The sperm of Uta and Urosaurus show strong similarities to those of the agamids and polychrotids. No spermatozoal autapomorphies for the Phrynosomatidae were found.

Purification and structural characterization of insulin from the lesser siren, Siren intermedia (Amphibia: Caudata)

Insulin has been isolated from an extract of the pancreas of a salamander, the lesser siren Siren intermedia, and its primary structure was established as: A-chain, Gly-Ile-Val- Glu-Gln-Cys-Cys-His-Asn-Thr10-Cys-Ser-Leu-Tyr-Gln-Leu-Glu-Asn-Tyr- Cys20-Asn, and B-chain, Val-Pro-Asn-Lys-Pro- Leu-Cys-Gly-Ala-His10-Leu-Val-Glu-Val-Met-Tyr-Phe-Val- Cys-Gly20-Asp-Arg-Gly-Phe-Phe-Tyr-Pro-Ser-Ser-Thr 30. Although those amino acid residues considered to constitute the receptor-binding region of insulin have been retained, siren insulin contains several substitutions (Gln-->Lys at B4, Ser-->Ala at B9, Ala-->Val at B14, Leu-->Met at B15, Leu-->Phe at B17, Pro-->Ser at B28, and Lys-->Ser at B29) of amino acid residues that are conserved in insulins from species of other amphibian orders. The biological activity of siren insulin was not investigated in this study but the substitutions at B28 (involved in dimer formation) and at B14 and B17 (involved in hexamer formation) may be expected to influence conformation and therefore biological potency. The data are consistent with the view that the Sirenoidea represent an early divergence from the ancestral stock of salamanders.

A new species of Chloromyxum (Myxozoa: Chloromyxidae) from the gall bladder of Eurycea spp. (Caudata: Plethodontidae) in North America

A previously undescribed species of Chloromyxum (Myxozoa: Chloromyxidae) was found in plasmodia adhering to the epithelium of the gall bladders in salamanders of the genus Eurycea (Caudata: Plethodontidae) from Arkansas and Texas (USA) in November, December, and January, 1987 to 1994. Bivalved spores of Chloromyxum salamandrae sp. n. from Eurycea multiplicata griseogaster (type host) were subspherical, with a mean size +/- SD of 8.3 +/- 0.3 x 7.7 +/- 0.4 (7.8 to 8.8 x 7.0 to 8.2) microns (n = 20), and had a shape index (length/width) of 1.07 +/- 0.03 (1.02 to 1.14). The valves measured 0.8 to 1.0 micron thick and had 10 to 12 external striations each. Each of the four polar capsules were piriform, with a mean size +/- SD of 4.0 +/- 0.1 x 2.6 +/- 0.1 (3.8 to 4.2 x 2.4 to 2.8) microns (n = 20), and there appeared to be about four coils of each polar filament. The sporoplasm was irregular in shape and appeared to be binucleate. Adherent plasmodia observed in winter months were small, with a mean size +/- SD of 31.5 +/- 6.3 x 24.9 +/- 2.6 (20 to 40 x 20 to 30) microns (n = 20), and contained zero to eight disporoblastic spores each. The myxozoan occurred in nine of 14 E. multiplicata griseogaster, three of eight E. multiplicata multiplicata, and two of 12 E. neotenes. This represents the first report of a Chloromyxum sp. from Amphibia in the Western hemisphere.