Oral Disc Research Articles

Morphometric and Karyological Differentiation Among Populations of <I>Discoglossus Pictus</I> (Discoglossidae: Anura) in Eastern North Africa

Abstract. To assess karyological and morphometric diversity within Discoglossus pictus Otth 1837, morphometric and cytogenetic analyses were carried out on five populations from the northern Tunisia and Algeria. A total of eight morphometric adult traits were evaluated, tadpole oral disc structure was described and chromosome patterns were assessed by means of conventional staining and banding methods (C-, Ag-NOR and CMA3 banding). Karyological data indicated the same chromosome and chromatin characters among the five populations. We observed also the same oral disk structure (LTRF: ⅔) in all studied Discoglossus tadpoles. However, we found significant differences in morphometric parameters of the specimens from these localities. Discriminant Function Analysis (DFA) of morphometric variables correctly classified 88% of individuals to their original localities. The pattern of morphometric variation does not match the genetic observation, which suggests that body shape differences result from the phenotypic...

Molecular and morphological characterisation of Sphaeronema alni Turkina & Chizhov, 1986 (Nematoda: Sphaeronematidae) from Spain compared with a topotype population from Russia

Abstract The occurrence of a male-less population of Sphaeronema alni parasitising chestnut (Castanea sativa) roots and inducing a stelar syncytium is reported for the first time in Pola de Somiedo (Oviedo province), Spain. Morphometric and molecular characters of the Spanish population matched those of a topotype population from Russia. SEM observations showed swollen females having the first lip annulus wider than the second and appearing as a cap-like, circumoral elevation. The second-stage juveniles, having a single band in the lateral fields, were characterised by a non-annulated dome-shaped lip region derived from the fusion of the oral disc with all the lip sectors and lip annuli, and showing slit-like amphidial apertures and an oval prestoma. The sequences of the D2-D3 expansion segments of 28S rRNA, partial 18S rRNA and ITS rRNA gene for the Spanish and topotype populations of S. alni were congruent and matched those deposited in GenBank for another population from Germany, thereby confirming their conspecificity. A PCR-RFLP profile of D2-D3 of 28S rRNA for identification of this species was also provided. The phylogenetic relationships between S. alni populations and representatives of the suborder Criconematina, as inferred from analysis of partial 18S rRNA and D2-D3 of 28S gene sequences obtained in this and previous studies, indicated that S. alni formed a basal clade on the majority consensus Bayesian phylogenetic trees, standing together with Meloidoderita sp. or alone. These findings provide additional evidence of the need to clarify the position of Sphaeronema within Criconematina and its relationships with representatives of Tylenchulinae.

A New Species of the Scinax catharinae Species Group (Anura: Hylidae) from Minas Gerais, Southeastern Brazil

A new species of tree frog from the Scinax catharinae species group is described, discovered in the Municipality of Ouro Preto, southeastern Brazil. The new species is related to Scinax flavoguttatus, but differs from this species mainly by the light green color on its inguinal regions and hidden portions of flanks and thighs, by its subovoid snout, by its developed nuptial pad, and by its smaller males and females. Additionally, we describe the tadpole which is characterized by: dorsal position of nostril; dorsolateral eyes; gold spots between nostrils and eyes, short spiracle; spiracle opening on the midline of dorsal and ventral surface of body; absence of tail flagellum; oral disc with a short dorsal gap, surrounded by a uniseriate marginal papillae; M- shaped upper jaw sheath; tooth row formula 2(2)/3.

The tadpole of Hypsiboas atlanticus (Anura, Hylidae) from northeastern Brazil

The tadpole of Hypsiboas atlanticus (Caramaschi & Velosa, 1996) is described from the municipality of Maceió, State of Alagoas, Brazil. At stage 36 the larvae have an overall elliptical body in lateral and dorsal views, oral disc anteroventral, spiracular tube sinistral, and labial tooth row formula 2(1,2)/3(1). The oral disc is surrounded, almost completely (anterior medial gap present) by a single row of marginal papillae. Described tadpoles of the H. punctatus species group can be differentiated by a combined disc oral features. Additional descriptions of H. punctatus (Schneider, 1799) tadpoles from populations throughout South America may be helpful in determining the status of these populations.

Specific identification of toads and frogs based on the mouthpart configuration of their tadpoles

The mouth part configuration of the tadpoles of some anuran amphibians were examined using a dissecting microscope. Features examined included the tooth rows, oral disc, and the jaw sheath. Two different groups of tadpoles were collected and suitable pond conditions provided for them to metamorphose into adults. One group metamorphosed to Bufo regularis and the other to Hyperolius nasatus. The Bufo regularis tadpoles had a jaw sheath that was serrate and valley-sawed with a Labial Tooth row Formula (LTF) of 2(2)/3. The Hyperolius nasatus tadpoles on the other hand had a jaw sheath that was cuspate pointed with a Labial Tooth row Formula of 2(2)(3)/3(3). The findings from this study show that it is possible to identify frogs and toads from their tadpoles without having to look for the breeding adults in the wild.

Reproductive Biology, Vocalizations, and Tadpole Morphology ofRupirana Cardosoi, an Anuran with Uncertain Affinities

ABSTRACT. We describe the tadpole morphology, the advertisement and courtship calls, and reproductive characteristics of Rupirana cardosoi Heyer 1999, an endemic species from rocky mountain fields in Chapada Diamantina, Bahia State, Brazil. Females of Rupirana cardosoi deposit pigmented eggs in shallow backwaters or ponds. The body of tadpoles is ovoid in dorsal and ventral views and depressed in lateral view. The oral disc is ventral and the labial tooth row formula is 2(2)/3(1). Eyes are dorsal. The advertisement call has one pulsed note, with dominant frequency approximately 1.3 kHz. The courtship call presents three note types with dominant frequency ranging from 0.7 to 1.4 kHz. Females are larger ( = 34.4, SD = 1.6, 31.4–37.4 mm, n = 12) than males ( = 30.9, SD = 1.5, 28.8–33.8, n = 9; t = 5.1; p < 0.001) and males present nuptial excrescences located on the base of the thumbs. The eggs are medium sized ( = 2.47 ± 0.52 mm, N = 27) and mean clutch size was 120.44 ± 74.38 eggs (N = 11 clutches).

The Tadpole ofPhyllomedusa itacolomi(Anura, Hylidae), with a Description of the Internal Oral Morphology

We describe the external morphology and the internal oral features of the tadpole of Phyllomedusa itacolomi (Anura, Hylidae) from Serra de Ouro Branco, Municipality of Ouro Branco, State of Minas Gerais, Brazil. Tadpoles were found at mid water in a temporary pool, in an open montane meadow. Phyllomedusa itacolomi (Gosner's stage 37) is characterized by a tooth row formula 2(2)/3(1), labial tooth row P3 smaller than P1 and P2, marginal papillae of oral disc with wide dorsal and narrow ventral gaps. External morphological features were compared with other tadpoles of the Phyllomedusa hypochondrialis species group. Additionally, we provide information on egg clutches of P. itacolomi and P. megacephala.

The tadpole of Odontophrynus cordobae Martino &amp;amp; Sinsch, 2002 (Anura: Cycloramphidae) from central Argentina

The genus Odontophrynus is endemic to South America and currently consists of 10 recognized species distributed in southern and eastern of the continent (Rosset et al. 2006; Rosset 2008; Amaro et al. 2009). The americanus group is currently represented by four species: O. americanus, O. lavillai, O. cordobae and O. maisuma. Odontophrynus cordobae is cryptic with their polyploid counterpart O. americanus and inhabited in the center and northwestern Córdoba and south of Santiago del Estero provinces (Martino and Sinsch 2002; Rosset et al. 2006). The tadpole of O. cordobae remains undescribed. Herein we describe the larval external morphology and oral disc.

Living in fast‐flowing water: Morphology of the gastromyzophorous tadpole of the bufonid Rhinella quechua (R. veraguensis group)

We describe the bufonid gastromyzophorous tadpoles of Rhinella quechua from montane forest streams in Bolivia. Specimens were cleared and stained, and the external morphology, buccopharyngeal structures, and the musculoskeletal system were studied. These tadpoles show a combination of some traits common in Rhinella larvae (e.g., emarginate oral disc with large ventral gap in the marginal papillae, labial tooth row formula 2/3, prenarial ridge, two infralabial papillae, quadratoorbital commissure present, larval otic process absent, mm. mandibulolabialis superior, interhyoideus posterior, and diaphragmatopraecordialis absent, m. subarcualis rectus I composed of three slips), some traits apparently exclusive for the described species of the R. veraguensis group (e.g., second anterior labial tooth row complete, lingual papillae absent, adrostral cartilages present), and some traits that are shared with other gastromyzophorous tadpoles (e.g., enlarged oral disc, short and wide articular process of the palatoquadrate, several muscles inserting on the abdominal sucker). In the context of the substantial taxonomic and nomenclatural changes that the former genus Bufo has undergone, and despite the conspicuous morphological differences related to the presence of an abdominal sucker, the larval morphology of R. quechua supports including it in the genus Rhinella and placing it close to species of the R. veraguensis assemblage.

Comparative larval morphology in Madagascan frogs of the genus Mantella (Amphibia: Mantellidae)

We describe and compare the tadpole morphology of nine species of frogs of the endemic Madagascan genus Mantella based upon specimens identified through DNA barcoding or captive bred. The tadpole morphology of M. crocea/ milotympanum-hybrids, M. madagascariensis, M. pulchra, M. viridis, M. baroni, M. bernhardi and M. betsileo is described for the first time. In general, Mantella have small and generalized tadpoles with a uniform dark colouration. The oral disc is elliptical, emarginated, and positioned anteroventrally. In M. laevigata the oral disc is rounded, not emarginated, and positioned ventrally; eyes are positioned and directed dorsally, while in other species they are directed dorsolaterally. Labial tooth row formulas of Mantella tadpoles differ among some species, and in M. aurantiaca and M. crocea/milotympanum they also show intraspecific variation. Species identification is difficult when considering only morphometric variables. Tadpoles within each species group of the genus do not cluster together (except for some clustering of species belonging to the M. madagascariensis group), confirming that the larval morphology in closely related Mantella species is not suitable for determining phylogenetic relationships. Mantella laevigata, distinguished by tree-hole breeding and parental care, shows the most distinguished larval morphology.

Giant Tadpole and Delayed Metamorphosis of Pseudis platensis Gallardo, 1961 (Anura, Hylidae)

Pseudis platensis, like Pseudis paradoxa, is a Neotropical aquatic frog with a giant tadpole. Despite being one of the few anuran species whose larvae grow larger than adults, knowledge of its larval development is limited to prometamorphic stages. This study describes qualitative and quantitative variation through P. platensis larval development, including descriptions of various traits (lateral line, oral disc, vent tube, limbs) and their transformations during metamorphosis. We found similarities with the development of other anurans at larval stages up to the end of prometamorphosis but not with their metamorphic stages. For this species, we described key features to characterize 13 ontogenetic stages as follows: four for prometamorphic larval morphologies, eight stages covering metamorphic changes, and one defining the posmetamorphic adult stage. At the end of prometamorphosis, tadpole body size in P. platensis is similar to adult size, but the tail shows extra development. Unlike most anurans, the disappearance of two larval traits (i.e., vent tube and tail) is delayed until later in metamorphosis. Larval development of P. platensis exhibits unique features not reported for other anurans and offers a model to study developmental and evolutionary aspects of anuran metamorphosis.

Serratotantulus chertoprudae gen. et sp. n. (Crustacea, Tantulocarida, Basipodellidae): A new tantulocaridan from the abyssal depths of the Indian Ocean

A single tantulus larva was found at the abyssal depth of the Indian Ocean attached to a harpacticoid host of the family Cletodidae. It represents a new genus and species of Tantulocarida, family Basipodellidae. Its ultrastructure was studied with SEM. This genus can be easily distinguished from the other genera of Basipodellidae by the pore pattern, bilobed oral disk with strong longitudinal ridges and the posterior projection of the cephalic shield. A morphological analysis of two related families Basipodellidae and Deothertridae shows that they represent polyphyletic taxa and need further revision.

Fossilized polyp remains in Silurian Heliolites (Anthozoa, Tabulata) from Nunavut, Arctic Canada

Dixon, O.A. 2010: Fossilized polyp remains in Silurian Heliolites (Anthozoa, Tabulata) from Nunavut, Arctic Canada. Lethaia, Vol. 43, pp. 60–72. Calices within a substantially silicified corallum of Heliolites garnieriDixon, 1996, from the lower part of the Barlow Inlet Formation (Ludlow) on south-western Devon Island, contain what appear to be the silicified remains of soft tissues of coral polyps. These remains apparently represent the peristomal portion of an oral disc, incorporating a symmetrical radial array of 12 spicules (intra-polyp sclerites), and a membrane-like, possibly epidermal structure. These remains, and more non-descript material in a few coralla belonging to two other species of Heliolites, occur at local intra-corallum discontinuities where polyps died, but the surrounding colony continued skeletal construction. Their preservation indicates that, before the organic remains were fully destroyed by decomposition, they were rapidly enclosed and sealed by precipitation of microcrystalline quartz or a precursor, and that the failed calices were capped rapidly by local construction of basal epitheca. Clusters of hollow microspheres were also preserved at these discontinuities, suggestive of micro-organisms with a predilection for sites of tissue decay; these microbial decay agents possibly helped to isolate microenvironments conducive to early precipitation of silica. □Canada, Heliolitidae, microspheres, Nunavut, silicified polyp remains, Silurian, Tabulata.

Getting in shape: adaptation and phylogenetic inertia in morphology of Australian anuran larvae

The external morphology of frog larvae is predicted to vary among habitats, for a variety of functional reasons. I performed a phylogenetic comparative study to test whether correlations between habitat and the shape of the tadpole and its oral disc are adaptive in 82 species from south-eastern Australia in the families Hylidae and Myobatrachidae. Habitat distributions and phylogenetic relationships were compiled from the literature and shape was quantified using geometric morphometric analysis of published drawings. Results indicate that shape evolved towards different optima in different habitats while also showing appreciable levels of phylogenetic inertia. Within myobatrachids, evolution of terrestrial tadpoles was associated with a short and shallow head/body and a shallow tail. In aquatic species, the use of benthic microhabitats was correlated with a long shallow tail, dorsal eye position, shallow head/body and ventral mouth with robust jaw sheaths. Even traits with evidence for adaptation evolved slowly in response to habitat shifts, usually requiring >or=10 million years to evolve half-way to a new optimum. Although these findings support adaptive evolution of tadpole body form, they also highlight a strong influence of ancestral character states and indicate that phenotypes in extant species are partly maladaptive.

Morphological variation in tadpoles of the Geocrinia laevis complex: regional divergence and hybridization (Amphibia, Anura, Myobatrachinae)

Morphological variation in tadpoles of Australian frogs of the Geocrinia laevis complex was studied using specimens preserved at predetermined sizes, that had been reared under laboratory conditions from field-collected egg masses. Univariate and multivariate statistical analyses of 24 metric characters included comparisons of G. laevis with two disjunct population groups of G. vicioriana, as well as descriptions of the variation across a hybrid zone between the two species. Geocrinia victoriana differed from G. laevis by having shorter interpupillar distances, but longer tooth rows and more oral papillae. The two regional groups of G. vicioriana were also distinct; larvae from south-western Victoria had the widest oral disks, whereas those from central Victoria showed the most narrowly positioned eyes. Most populations from the hybrid zone were more similar to G. laevis in tadpole morphology than in call parameters, adult morphology, or frequencies of allozyme markers. Morphological aberrations did not occur in increased frequencies in larvae from the hybrid zone.

Keratodont formulae in anuran tadpoles: proposals for a standardization

The various systems proposed to describe concisely, in the form of a formula, the number and arrangement of keratodont rows in the oral disk of anuran tadpoles, are reviewed and classified. A distinction is made between individual and collective keratodont formulae. The different systems are compared and evaluated, and proposals are made to standardize the use of various signs, numerals and letters in keratodont formulae. Nine standardized systems (seven all-cardinal and two cardinal-ordinal systems) are finally retained: these should cover all needs according to the kind of use and the level of precision required.

Natural History ofPhyllomedusa centralisBokermann 1965 (Anura: Hylidae: Phyllomedusinae): Tadpole and Calls

ABSTRACT. The tadpole and vocalizations of Phyllomedusa centralis are described based on individuals from the type locality, Chapada dos Guimaraes, State of Mato Grosso, Brazil. An opaque abdomen, upper jaw sheath medially higher, and an abundance of oral disc papillae characterize the tadpole of P. centralis. Phyllomedusa centralis, P. ayeaye, P. oreades, and P. megacephala are similar in inhabiting small streams, larvae with medially high upper jaws sheaths, spiracle opening free from body, and a ventral fin about three times deeper than the dorsal fin. The vocal repertoire of P. centralis consists of three different calls (“single call”, “compound call”, and ”response call”). These calls differ from those of other species of the hypochondrialis group by their low dominant frequency, short note duration, and broad frequency range with minimum (fundamental) and maximum frequencies coincident with the dominant frequency.

Three new species of shallow water, yellow zoanthids (Hexacorallia: Zoanthidea: Epizoanthidae) from southern California, USA, and southern Australia

In southern California and southern Australia, several species of hexacorals that are common at diving depths have been referred to as “Yellow Zoanthids.” We describe three new species of them in the genus Epizoanthus because all have a macrocnemic mesenterial arrangement and mesogleal marginal sphincter muscle. Epizoanthus giveni is from southern California, and Epizoanthus karenae and Epizoanthus rodmani are from southern Australia. Distinguishing features of E. giveni n. sp. are a sphincter muscle with alveoli arrayed in a single, longitudinal column, polyps no longer than 8 mm beyond the coenenchyme, obvious scapus ridges numbering 19 or fewer, and mesenteries numbering 36 or fewer. Distinguishing features of E. karenae n. sp. are radiating dark-orange lines on the oral disc (in life), a broad sphincter muscle filling most of the margin distally and transversely stratified proximally, polyps no longer than 12 mm beyond the coenenchyme, obvious scapus ridges numbering 20 or fewer, and mesenteries numbering no more than 40. Distinguishing features of E. rodmani n. sp. are the lack of lines on the oral disc (in life), a sphincter muscle situated in the middle of the mesoglea with alveoli more elliptical than circular in section, polyps no longer than 8 mm beyond the coenenchyme, scapus ridges not obvious, and mesenteries numbering 48 or fewer.

Isozoanthus antumbrosus, a new species of zoanthid (Cnidaria: Anthozoa: Zoanthidea) symbiotic with Hydrozoa from the Caribbean, with a key to hydroid and sponge-symbiotic zoanthid species

Isozoanthus antumbrosus, a new species of zooxanthellate zoanthid, is described. Colonies associate with the arborescent hydroid Dentitheca dendritica in the Caribbean Sea at 1–60 m. The coenenchyme, column, and oral disk are seal brown. The tentacles are golden brown and number 30–38. The coloration of the oral disk and tentacles recalls an annular solar eclipse. Polyps are 4.1–8.9 mm long and 2.2–4.3 mm in diameter. Genetic, morphological, and ecological characters differentiate this species from other hydroid-symbiotic zoanthids. Assignment to the genus Isozoanthus is based on morphology, with the acknowledgment that the currently accepted genera may not reflect evolutionary relationships.

Larval morphology in four species of Hylarana from Vietnam and Thailand with comments on the taxonomy of H. nigrovittata sensu latu (Anura: Ranidae)

We describe the tadpole morphology of four species of Hylarana based on larval specimens identified by DNA barcoding. Of these, the larvae of Hylarana attigua and H. maosonensis, two species recently recorded from Phong Nha – Ke Bang National Park, Quang Binh Province, central Vietnam, had not been previously described; in addition, descriptions of the tadpoles of syntopic H. guentheri and H. nigrovitatta are provided as well. The tadpoles of these four species are generalized exotrophic lentic-benthic forms of Orton’s Type 4 with a depressed body shape, dorsolaterally positioned eyes and a moderate height of tail fins. In contrast to the silver-whitish H. guentheri the preserved tadpoles of H. attigua, H. maosonensis and H. nigrovittata are greenish-brown to greyish. The generalized oral discs exhibit a wide gap of marginal papillae on the upper labium and elongated papillae on the lower labium. In general, the keratodont row formulae of the Hylarana species studied herein is 2(2)/3(1) (sometimes 1/3(1) in H. guentheri). Differences between species mainly concern body shape, size in different developmental stages as well as number and shape of oral papillae. H. nigrovittata larvae from near Chiang Mai in northern Thailand mainly differ from Vietnamese specimens in the number and shape of oral papillae. In concert with adult morphological differences and molecular divergences by molecular data this indicates species-level distinctness of the Vietnamese versus the northern Thai populations.