Rachidian Tooth Research Articles

Integrative taxonomy and phylogeography of the genus Acanthodoris (Gastropoda: Nudibranchia) in the Russian seas, with the description of a new genus

The nudibranch genus Acanthodoris Alder et Hancock, 1845 includes 15 recognised species, most of which are distributed in the temperate marine waters of both hemispheres, but only two species were known from the Russian seas: the widely distributed trans-Arctic A. pilosa (Abildgaard in Müller, 1789) and A. uchidai Baba, 1935, which is found from in the Kuril Islands. The main aim of this study is to revise the species composition of Acanthodoris in Russian waters, evaluate the genetic population structure of the trans-Arctic A. pilosa in the context of connectivity among its distant populations, and infer the phylogenetic relationships between the Russian species of Acanthodoris and other representatives of the family Onchidorididae. The material was collected from eight localities in the subarctic and North-West Pacific waters. The methods employed included morphological analyses, particularly, scanning electron microscopy and computer microtomography, as well as molecular analyses of partial fragments of genetic markers: cytochrome c oxidase subunit I, 16S rRNA, histone H3, 28S rRNA, and 18S rRNA. The genus Acanthodoris is represented in the Russian seas by two species: the North Atlantic and subarctic A. pilosa and the North Pacific A. atrogriseata O’Donoghue, 1927, which is recorded here for the first time from Russia. Acanthodoris uchidai represents a separate clade that is not related to other Acanthodoris; therefore, a new genus Acanthomira gen. nov. is proposed herein, with a single representative species Acanthomira uchidai, comb. nov. We also provide evidence for the existence of cryptic biodiversity within North Atlantic A. pilosa. Our current phylogenetic hypothesis suggests an independent loss of the rachidian teeth in both Acanthodoris and Acanthomira gen. nov., although this should be further tested with a larger taxon sampling. The results of this study emphasise the necessity of incorporating molecular analyses to confirm species identity and to prevent the description of new Nudibranchia taxa based solely on subtle morphological differences.

Redescription and geographical distribution of Leiostracusobliquus (Reeve, 1849) (Mollusca, Gastropoda, Simpulopsidae).

Leiostracus Albers, 1850 was established to allocate land snails from Central America and Northern South America. Currently, approximately 19 species are considered valid. However, for most of them, the internal morphology is unknown. Leiostracusobliquus was described as a species of Bulimus from the state of Bahia based on shell characters. Until now, knowledge of this species has been scarce. The discovery of ethanol-preserved specimens from MZSP of this species allowed us to characterize, for the first time, the internal anatomy of this species and update its distribution. The shell of L.obliquus has seven to eight whorls and a wide pale-pink disrupted band all over the teleoconch. The rachidian tooth is small rectangular, symmetric, with round edges, and without differentiated cusps. After comparing the anatomy and radular characters between the shells of L.obliquus and L.carnavalescus, we found remarkable similarities in the morphology and color pattern.

Ontogenetic Shifts of Predatory Strategies by the Carnivorous Gastropod Acanthina monodon (Pallas, 1774)

Predatory strategies used by carnivorous gastropods may change during their ontogeny. In muricid gastropods attack mechanisms include an accessory boring organ (ABO), radula, labral tooth and/or pedal muscle. However, these mechanisms and their patterns of use in relation to the ontogeny of the carnivorous gastropod remain uncertain. We studied the occurrence of shifts in predatory strategies through the ontogeny of the gastropod Acanthina monodon preying on the mytilid Perumytilus purpuratus. Our results showed a direct relationship between predator and prey size. During attack, the small-sized snails (up to 18 mm shell length, SL) used exclusively the ABO, and medium-sized snails (18–20 mm SL) shifted to using the radula for rasping shells. Meanwhile, the largest-sized snails (> 20 mm SL) used the radula, but also occasionally the pedal muscle and labral tooth, to attack their prey. The site selectivity on the mytilid shell varied according to predatory mechanisms used. The small-sized gastropods used the ABO to drill the center of the prey valves, whereas mid-sized and large-sized snails used the radula and the labral tooth on the valve edges. Occasionally, large-sized snails also used ABO. Shifts in predatory strategies and attacked areas are influenced by the development and consolidation of structures involved in the attack as predator size increased. The incorporation of trace elements during rachidian teeth growth may enable major resistance to friction against carbonate prey valves, as well as the appearance and development of the labral tooth, play relevant roles in the predatory mechanism shifts, which allows the consumption of larger prey. These patterns described evidences the gastropod's predatory behaviour in terms of energetic gain while minimizing the risk of the predator itself being preyed on.

Costapex baldwinae, a new species of bathyal costellariid (Mollusca: Gastropoda: Neogastropoda: Costellariidae) from the Caribbean Sea

Costapex baldwinae, new species, is described from deep reef habitats of the southern and eastern Caribbean Sea, including Curaçao, Dominica and Guadeloupe, where it occurs at bathyal depths on sunken wood. It is assigned to the genus Costapex based on phylogenetic analyses using partial sequences of COI, 12S and 16S mitochondrial genes that reveal it to be the sister species of two Indo-Pacific members of this genus. This new species most closely resembles Costapex martinorum (Cernohorsky, 1986) from the Philippines, but differs in being smaller, and in having a slightly lower spire and more prominently beaded spiral sculpture. Of the Caribbean species of costellariids, it is somewhat similar to Nodicostellaria laterculata (Sowerby II, 1874), which occurs in shallower water and has a white or tan rather than dark brown shell, and also a taller spire, more prominent axial sculpture, and a more rounded aperture. It differs from Vexillum styria (Dall, 1889), with which it co-occurs, in having a broader shell with a lower spire, prosocline rather than opisthocline axial ribs, and more prominent, strongly beaded spiral cords. Costapex baldwinae differs from both these taxa in having rachidian teeth with three cusps rather than five cusps (N. laterculata) or seven cusps (V. styria). The genus Costapex was previously known only from Indo-Pacific species. The discovery of this new species represents a significant expansion of the range of this genus into the Caribbean Sea.

Radular morphology by using SEM in Pugilina cochlidium (Gastropoda: Melongenidae) populations, from Thondi coast-Palk Bay in Tamil Nadu-South East coast of India.

Radula in all melongeninae species is rather uniform and characterized by bicuspid lateral teeth with strongly curved cusps and sub rectangular rachidians, bearing usually 3 cusps. The aim of the present study was to describe the radula of 2 Pugilina cochlidium populations using SEM. The radula in 2 species proves itself as a rachiglossate type showing the radular formula of 1 + R + 1. The first population hasthe central tooth wide with sharp cusps equal in length, emanate from posterior margin of tooth base. The lateral teeth have 2 cusps and are long, sharp, pointed and bent towards the rachidian tooth. Whereas the second population, the central tooth is narrow with sharp cusps equal in length, emanate from posterior margin of tooth base. The lateral teeth have 2 cusps and are broad, longer, sharp, pointed and bent towards the rachidian tooth. They are typically sickle shaped with broad strong base. In both populations the rachidian tooth is subquadrate with 3 big cusps in the middle, but in the second population the base of the rachidian is concave while in the first population it is straight. In the present study the median rachidian of the second population, has a broad basal region when compared to first. This similar observation has been made in Chicoreus virgineus ponderosus and Siratus virgineus ponderosus. In the present study, since 2 populations exhibit the same generalized rachiglossate pattern it does not offer much scope for systematic diagnosis below generic level.

A report of a new species and new record of Cadlina (Nudibranchia, Cadlinidae) from South Korea.

Of the four species in the genus Cadlina present in the northwestern Pacific region, C. japonica has been the only species recorded from South Korea. For the purpose of investigating Cadlina in Korean waters, specimens were collected from the Korean East Sea (Sea of Japan) by scuba diving. The radula and morphology of these specimens were examined by stereoscopic and scanning electron microscopy. Based on morphology, three species were identified in Korean waters, including the new species, Cadlina koreanasp. nov., C. umiushi (first record in South Korea), and C. japonica. Cadlina koreanasp. nov. somewhat resembles C. umiushi but differs in both its morphology as well as the structure of its radula. The background color of Cadlina koreanasp. nov. is translucent white, tubercles on the dorsum are opaque white and the yellow marginal band is absent. The radular formula of Cadlina koreanasp. nov. is 57 × 23.1.23 with a rectangular rachidian tooth. In addition, mitochondrial cytochrome c subunit 1 (COI), 16S ribosomal RNA (16S rRNA), and nuclear 28S ribosomal RNA (28S rRNA) gene sequences were generated and used for analysis of Automatic Barcode Gap Discovery (ABGD) and reconstruction of the phylogenetic tree. Morphological distinction and genetic analyses confirm that three Cadlina species are present in Korean waters of which Cadlina koreana is a new species.

Renewal mechanisms of buccal armature in Flabellina verrucosa (Nudibranchia: Aeolidida: Flabellinidae)

The general and fine morphology of the buccal armature and concomitant epithelia in Flabellina verrucosa were examined using light microscopy, cLSM, TEM, and SEM. A 3D-reconstruction of the radular sheath terminal end was constructed as well. Based on the obtained data, we suggest the mechanisms of jaw and radula syntheses for this species. The jaw plate’s growth is provided by the apocrine secretion of the gnathoblasts. There are two primary areas of jaw synthesis: the anterior area is responsible for growth formation of the jaw portion used in the masticatory process, and the posterior area provides the growth of the jaw plate. These types of synthesis (common for both areas) were described in detail for the first time for Gastropoda. The radula growth is provided by the microvillar activity of odontoblasts and membranoblasts. The rachidian tooth is synthesised by a single cell, and the lateral teeth are synthesised by group of 3–5 cells. The tooth formation includes four main stages: (1) tooth mould formation; (2) 90° turn of the tooth mould; (3) chitin accumulation, and (4) tooth maturation. The wide range of synthesis mechanisms is provided by a combination of two factors: the type of secretion and the amount of cells.

A new diplommatinid genus and two new species from the Philippines (Gastropoda, Caenogastropoda, Cyclophoroidea).

A new diplommatinid genus, Luzonocoptis Páll-Gergely & Hunyadi, gen. n. is erected for two new species, Luzonocoptis antenna Páll-Gergely & Hunyadi, sp. n. and L. angulata Páll-Gergely & Hunyadi, sp. n. Both species inhabit the northeastern part of Luzon Island, Philippines. The genus Luzonocoptis gen. n. is mostly characterized by a very slender shell with 14–18 whorls, a strongly expanded peristome, an interrupted, weak columellar lamella, the absence of any additional plicae or lamellae, and a rachidian tooth having five cusps.

On the genus Armina (Gastropoda: Heterobranchia: Nudibranchia) in Thailand

The marine sea slug heterobranch fauna from Thailand is composed of a total of 240 species, and Armina semperi is the only representative of the genus Armina recorded in the country. This species, described in the Philippines in the nineteenth century, has an uneasy taxonomic history and appears to be part of a complex of morphologically similar species, which has made its real identity difficult to determine. Comparison of samples of the genus Armina from Thailand with the original description of A. semperi showed that they were different. Furthermore, additional sampling allowed the discovery of a second species of the genus, similar to the so-called A. semperi and living in sympatry with it. In this paper, the taxonomic history of A. semperi is summarized and both species from Thailand are described as new to science. Armina scotti n. sp. is characterized by its black dorsum with pale yellowish notal ridges, widened forming three rounded blotches, not divergent posteriorly, not bifurcated; oral veil white, with a pale blue submarginal band and yellow edge; white rhinophores with a black subterminal band, which is pale blue on the inner-front sides, orange tips, and a black stripe running to the sides of the oral veil. The cutting edge of the jaws with up to four rows of denticles; radular formula 28 x 20.1.1.1.20; rachidian tooth with 5–6 strong denticles on each side of the median cusp; lateral teeth denticulate to smooth. Hermaphrodite duct very thin. Ampulla very long and wide; bursa copulatrix absent; prostate not differentiated; and penis proportionally very large and unarmed. Armina occulta n. sp. is characterized by its black dorsum with white notum narrowed forming two transverse dark bands, divergent and bifurcated posteriorly; orange mantle edge; black foot with a thick marginal band of deep blue; rhinophores deep blue with yellow tips, and a black subterminal band. The radular formula is 50 x 29.1.1.29; broad rachidian teeth, bearing 4–6 strong denticles only on the left side of the median cusp; a very thin hermaphrodite duct; very long and wide ampulla; undifferentiated prostate; large bursa copulatrix; and a penis bearing a stylet.

Radular Morphology of Extinct Pleurocerids (Gastropoda: Cerithioidea: Pleuroceridae)

Abstract: The freshwater gastropod family Pleuroceridae suffers from a disproportionately high number of imperiled species and recent extinctions. As pleurocerid diversity has been lost, so too has our ability to study the biology of these animals. However, many extinct species were deposited in natural history collections before their demise. I extracted radulae from dried tissue left in shells of seven extinct species in three genera (Leptoxis Rafinesque, 1819, Gyrotoma Shuttleworth, 1845, Lithasia Haldeman, 1840) to gain insights into the morphological differences separating species and provide data for future researchers. There were notable intergeneric and interspecific differences in radular morphology such as shape of cusps (e.g., dagger-like vs. blunt) and number of denticles on the rachidian, lateral, and marginal teeth. Interestingly, the degree of radular differences among Leptoxis spp. likely corroborates previous hypotheses that the genus is not a natural group. These data are a resource for ...

Review ofPugilinafrom the Atlantic, with Description of a New Species from Brazil (Neogastropoda, Melongenidae)

The anatomy of Brazilian and African specimens of Pugilina morio, a supposedly amphi-Atlantic species, is described in detail in this paper. Two different entities are recognised. The first is the true Pugilina morio, which is now restricted to the western African coast, from Senegal to Congo. The remaining species is Pugilina tupiniquim sp. n., described herein as the single Brazilian melongenid species known so far, distributed from the Caribbean to Brazil (Para to Santa Catarina states). The two species showed important anatomical discrepancies, and differ in the position of the tentacles, size of the neck, diameters of the aortas, diameter of the posterior oesophagus, and other features described below. A bursa copulatrix and rachidian teeth bearing a central cusp are both exclusive to P. morio.

Radula Development in the Giant Key-Hole LimpetMegathura crenulata

Changes in the morphology of the radula in the giant key-hole limpet (GKL) were analyzed including radula length, width, number of rows, and the morphology of the teeth in each row through ontogeny. In postlarvae with a shell length (SL) of 700 mm, the radula is ∼240 mm long and composed of about 30 rows of teeth. Each row has a central rachidian tooth, which has a pointed tip similar to the three pairs of lateral teeth on either side. These are flanked by five pairs of marginal teeth. In GKL with an SL of ∼2 mm, the teeth are larger, the rachidian tooth no longer has a triangular tip and lies flat along the radular ribbon except for a curled cusp. The most distal lateral tooth is larger than the other lateral teeth and has a sharply pointed tip, and the number of marginal pairs has increased from 18 to 20. InGKLwith an SL of 6–8 mm, the radula is∼2mmlong. The large, flat rachidian tooth overlaps and covers the laterals except the fifth lateral, which is now much larger and tapers to a sharp point. By the time GKL have an SL of 11 mm, the radula is about 3 mm long and tooth morphology is the same as in larger animals except for a gradual increase in tooth size and differentiation of the marginal tooth tips into three varieties. Scanning electron microscopy with energy-dispersive X-ray spectroscopy demonstrates that the radula is not mineralized and signs of wear and breakage are common on teeth in the first five to seven rows, the rows that are actually extended out of the mouth during a feeding motion.

Phylogeny and systematics of mitriform gastropods (Mollusca: Gastropoda: Neogastropoda)

With about 800 Recent species, ‘miters’ are a widely distributed group of tropical and subtropical gastropods that are most diverse in the Indo-West Pacific. They include the two families Mitridae and Costellariidae, similar in shell morphology and traditionally treated as close relatives. Some genera of deep-water Ptychatractidae and Volutomitridae are close to miters in shell morphology, and the term ‘mitriform gastropods’ has been introduced to refer to Mitridae, Costellariidae, and this assortment of convergent forms. The present study aimed at the reconstruction of phylogenetic relationships of mitriform gastropods based on representative taxon sampling. Four genetic markers [cytochrome c oxidase subunit I (COI), 16S and 12S rRNA mitochondrial genes, and H3 (Histone 3) nuclear gene] were sequenced for over 90 species in 20 genera, and the molecular data set was supplemented by studies of radula morphology. Our analysis recovered Mitridae as a monophyletic group, whereas the genus Mitra was found to be polyphyletic. Of 42 mitrid species included in the analysis, 37 formed a well-supported ‘core Mitridae’ consisting of four major clades, three of them consistent with the subfamilies Cylindromitrinae, Imbricariinae, and Mitrinae, and Strigatella paupercula standing out by itself. Basal to the ‘core Mitridae’ are four minor lineages, with the genus Charitodoron recognized as sister group to all other Mitridae. The deep-water family Pyramimitridae shows a sister relationship to the Mitridae, with high support for a Pyramimitridae + Mitridae clade. Our results recover the monophyly of the Costellariidae, which form a well-supported clade that also includes Ptychatractidae, Columbariinae, and Volutomitridae, but not Mitridae. Most derived and diverse amongst Costellariidae are species of Vexillum, characterized by a bow-shaped, multicuspidate rachidian tooth. Several previously unrecognized deep-water costellariid lineages are revealed. Their members retain some plesiomorphies – in particular a tricuspidate rachidian tooth – that makes them morphologically intermediate between ptychatractids and Vexillum. The taxa of Ptychatractidae included in the analysis are not monophyletic, but form three well-supported, unrelated groupings, corresponding respectively to Ceratoxancus + Latiromitra, Exilia, and Exiliodea. None of them shows an affinity to Pseudolividae. © 2015 The Linnean Society of London

Morphological Development of the Radula of Four Species of the Neogastropod Family Muricidae

Radular ontogenies of four species of the neogastropod family Muricidae are described through comparisons of early post-metamorphic and adult developmental stages, with specific focus on the rachidian (central) tooth. The degree of rachidian transformation during ontogeny varies from minor shape change to addition or loss of structural features important for assigning taxa to subfamilies. Changes include: flattening of the rachidian base and a switch from a short, beak-like to a long, flattened central cusp in the rapanine Stramonita biserialis; a switch from variable, asymmetric to regular, symmetric expression of inner lateral denticles in the basal muricid Timbellus phyllopterus; curvature of the rachidian base at the margins and separation of the pointed base endpoint from the radular membrane to form a marginal cusp in the muricine Chicoreus dilectus; and moderate straightening of the rachidian base in the ocenebrine Vokesinotus perrugatus. From these observations and previous work, we propose a plesiomorphic developmental sequence for the Muricidae and provide supporting evidence for the developmental origins of novel features of the muricid radula.

Describing the Radular morphology by using SEM in Muricanthus kuesterianus (Tapparone-canefri1875) Family: Muricidae, from Palk Bay-South East Coast of India

Scanning electron microscopic studies (SEM) revealed that the radula of Muricanthus kuesterianus resembled that of Muricanthus virgineus in most details. But there were some apparent differences. In Muricanthus kuesterianus rachidian tooth have a broad base than that of Muricanthus virgineus. The base of the median cusp was broad, short, stout and pointed straight towards the anterior end. The left lateral cusp elongated, sharp, slightly bent and pointed outwards and the right lateral cusp dorso ventrally flattened and the anterior end small, slightly pointed. In between the median and left lateral cusps, a sharp and pointed denticle is present where as the right laterals and median cups there is no denticle. The lateral teeth which are two in numbers flanked median rachidian.Keywords: Scanning Electron Microscope, Radula, Gastropoda, Muricidae, Muricanthus kuesteianus,

Wave‐induced changes in seaweed toughness entail plastic modifications in snail traits maintaining consumption efficacy

Summary Environmental stress can influence species traits and performance considerably. Using a seaweed–snail system from NW (Nova Scotia) and NE (Helgoland) Atlantic rocky shores, we examined how physical stress (wave exposure) modulates traits in the seaweed Fucus vesiculosus and indirectly in its main consumer, the periwinkle Littorina obtusata. In both regions, algal tissue toughness increased with wave exposure. Reciprocal‐transplant experiments showed that tissue toughness adjusted plastically to the prevailing level of wave exposure. Choice experiments tested the feeding preference of snails from sheltered, exposed and very exposed habitats for algae from such wave exposures. Snails from exposed and very exposed habitats consumed algal tissues at similar rates irrespective of the exposure of origin of the algae. However, snails from sheltered habitats consumed less algal tissues from very exposed habitats than tissues from sheltered and exposed habitats. Choice assays using reconstituted algal food (triturated during preparation) identified high thallus toughness as the explanation for the low preference of snails from sheltered habitats for algae from very exposed habitats. Ultrastructural analyses of radulae indicated that rachidian teeth were longest and the number of cusps in lateral teeth (grazing‐relevant traits) was highest in snails from very exposed habitats, suggesting that radulae are best suited to rupture tough algal tissues in such snails. No‐choice feeding experiments revealed that these radular traits were also phenotypically plastic, as they adjusted to the toughness of the algal food. Synthesis. This study indicates that the observed plasticity in the feeding ability of snails is mediated by wave exposure through phenotypic plasticity in the tissue toughness of algae. Thus, plasticity in consumers and their resource species may reduce the potential effects of physical stress on their interaction.

Comparative anatomy of the fasciolariids <em>Pustulatirus ogum</em> and <em>Hemipolygona beckyae</em> from Brazil (Gastropoda: Buccinoidea: Peristerniinae)

The Brazilian species Pustulatirus ogum and Hemipolygona beckyae were examined, and certain morphological characters were described. Both species were originally assigned to the genus Latirus, considered as a heterogeneous complex. The radulae of both species are like that which characterizes Latirus, in which the innermost cusp of the rachidian tooth is well developed but always smaller than the other cusps. This feature differs from Leucozonia, in which this cusp is reduced or absent. The penis tapers terminally, and the tapered part may be long (more than half the total penis length), as in H. beckyae, or very short (less than half the total penis length), as in P. ogum. The anatomical data observed in both species are discussed under the framework of fasciolariid systematics and they appear to be widespread among other fasciolariid species. For this reason, to date, the soft-part features here provided and those known from previously studied species of Latirus are not useful for delineating precise generic diagnoses.

A new species of Cerithium (Gastropoda: Cerithiidae) from the South China Sea

Specimens of a new species of Cerithiidae, Cerithium mangrovum n. sp., were collected during two surveys along the coasts of Hainan and Guangdong Province, China. Usually associated with potamidid snails, this species often occurs in large populations between the mid-high tidal zones in a range of habitats, including mangroves, grass beds, silt, mud, and coral reefs. C. mangrovum n. sp. has a slender and tapering shell and the straight-sided whorl bears three aligned beaded spiral cords. The thick outer lip has a wide posterior sinus. It morphologically resembles C. coralium Kiener, 1841. The shell of C. coralium is usually larger and wider and the spiral cords are not as beaded as in C. mangrovum n. sp. Its radula has a rachidian tooth with a shallow, wide, median basal projection while the rachidian tooth of C. mangrovum n. sp. has a moderately long, median basal projection.

Developmental origins of complex radular characters in the Muricidae: the bifid rachidian edge

AbstractMuricid gastropod radulae are more complex than those of most other neogastropods, especially in the number and variety of cusps, denticles, and interlocking mechanisms. How this complexity evolved, however, is unknown. Morphological gaps between higher taxa within the Muricidae are substantial, and there are few unambiguous intermediates. Here, we use developmental data from the Patagonian trophonine muricid Trophon geversianus to investigate the evolution of an unusual condition in which there are two marginal cusps at each end of each central rachidian tooth, rather than one or none as in most muricids. Trophon geversianus begins ontogeny with one marginal cusp (the inner marginal cusp), but a second (the outer marginal cusp) appears later, arising from separation of the rachidian base edge from the radular membrane rather than through bifurcation or lateral migration of pre‐existing cusps. Truncation of development (i.e., paedomorphosis) at this second developmental phase in a trophonine ancestor provides an explanation for the lack of transitional forms between most adult trophonine muricids, which have the plesiomorphic condition of one marginal cusp, and sister group ocenebrine muricids, which have the derived condition of two marginal cusps.

A new species ofTritonia(Opisthobranchia: Nudibranchia: Tritoniidae) from the tropical South Atlantic Ocean

A new species of the family Tritoniidae is described from the tropical South Atlantic Ocean. The animal was found off north-east Brazil.Tritonia khaleesisp. nov. is up to 12 mm long, with a slender white body, of which the notum is covered with one broad white band extending from between the eyes and veil to the tail; veil with 4 velar appendages; retractable white rhinophores; rhinophoral sheath with fleshy extension; seven pairs of branchial plumes; the anus is located between the 3rd and 4th gills on the right side, and the genital opening is under the 2nd gill. Internally,T. khaleesisp. nov. is distinguished from other tritoniids by jaws with 10–14 rows of denticles on the inner lips, absence of stomach plates and the radular formula 32 × 2–5.1.1.1.2–5 teeth.Tritonia khaleesisp. nov. is the onlyTritoniathat possesses a unicuspid rachidian tooth as an adult.