Rows Of Denticles Research Articles

Denticle rows on appendages of larvae in twelve species of Phytoseiidae (Parasitiformes: Mesostigmata)

The larval stages of phytoseiid mites (Acari: Phytoseiidae) are rarely considered in taxonomic descriptions. The presence of denticles on the palpi and legs is rarely documented in any developmental stages of mites of this family. To address this gap, the presence of denticles was evaluated on the appendages of larvae of the following twelve species: Amblydromalus limonicus (Garman and McGregor), Amblyseius herbicolus (Chant), Amblyseius orientalis Ehara, Amblyseius taiguensis Liu, Ma and Fan, Euseius utilis (Liang and Ke), Neoseiulus benjamini (Schicha), Neoseiulus californicus (McGregor), Neoseiulus setarius Ma, Meng and Fan, Neoseiulus womersleyi (Schicha), Neoseiulus zwoelferi (Dosse), Phytoseiulus persimilis Athias-Henriot and Phytoseius hongkongensis Swirski and Shechter. We identified and described the denticles on the palps, basis capitulum, and specific leg segments of these species, and hypothesized that the denticle rows might potentially be used for tearing open their own epidermis during hatching.

Description of Ornithodoros (Pavlovskyella) tartakovskyi using scanning electron microscopy, with notes on the morphology of Pavlovskyella sensu stricto and Theriodoros subgenera

Accumulation of DNA sequence data and its use in systematics of the family Argasidae reveals new incongruencies between genera and subgenera, since several groups defined by classical taxonomy appear to be paraphyletic, which is the case of the subgenus Pavlovskyella. In order to identify morphological characters unique to one of the monophyletic groupings within Pavlovskyella and improve its system, we describe all active stages of Ornithodoros (Pavlovskyella) tartakovskyi, a species with an incomplete original description. Larvae, nymphs, males and females from Iran were examined with scanning electron microscopy (SEM). The larva of O. (P.) tartakovskyi lacks dorsal plate, posteromedian seta, postcoxal setae and a spinose area in palpal article I; the dorsal surface has 13 pairs of setae and the hypostome has two short rows of denticles in the apex only. The first nymphal instar (N1) has a micromammillated body with faint dorsal and ventral disks. The second nymphal instar (N2) shows mammillated body with an incipient hood, and dorsal disks outlined as in subsequent instars. Both N1 and N2 have a small patch of glabrous surface in the anterior margin of preanal groove, absent in posterior stages. Third nymphal instar (N3) has a small hood and lack cheeks, which are incipient in the fourth nymphal instar (N4). The four nymphal instars (N1–N4) have blunt hypostomes, striated capitula, non-mammillated legs, and 3 humps on tarsi I. Females and males of O. (P.) tartakovskyi have mammillated bodies, small cheeks not covering the capitulum, the anteromedian disk is placed anteriorly to anterior central disks, and a posterior median file of disks is merged with the median disk. We describe all postembryonic stages of O. (P.) tartakovskyi providing morphological characters that define Pavlovskyella sensu stricto and Theriodoros, a sister subgenus that includes similarly shaped species.

Redescrption of Species of Mylonchulus Amurus, Khan and Jairajpuri, 1979 (Nematoda: Mononchida) In Himayatbag Region District Aurangabad (M.S.) India

The survey of plant nematodes were carried out during 2013-14. During this period the plant nematodes collect and observed. The species is characterized by body length 1.02 mm, ventrally curved upon fixation, buccal cavity1/3rd of its width and bears dorsal tooth opposed by five transverse rows of denticles ,length of oesophagus 1/4th of total body ,oesophagous intestinal junction non tuberculate ,gonad didelphic-amphidelphic, ovary small reflexed , tail short. All these characters are observed in Mylonchulus amurus hence the nematode is identified confirm to be redescribed species Mylonchulus amuru, Khan and Jairajpuri 1979.

Review of Admirandus Belogurov & Belogurova, 1979 (Nematoda, Oncholaimidae) with the description of a new species and the first record of the genus from Brazil

The present study provides a description of a new Admirandus species from northeastern Brazil, together with an updated species identification key. Admirandus capibaribei sp. n. can be distinguished from all the other Admirandus species by its physical dimensions (body length, a, stoma and spicule ratios), sexual dimorphism of the tail, the absence of pre-cloacal supplements, and the presence of a row of denticles at the base of the right ventrosublateral tooth. While Admirandus has been reported from temperate, subtropical and tropical environments around the world, this is the first record of the genus from Brazil. Further research on Admirandus and other Adoncholaiminae species, which include the integration of morphological and molecular approaches, will be important to provide a better understanding of the taxonomy of this group, as well as on its demanian system.

A new genus and species of Eviphididae Berlese (Acari: Mesostigmata) associated with an earth-boring dung beetle (Coleoptera: Geotrupidae) in Nepal

We describe a new monotypic genus in the mite family Eviphididae, Platyphis Joharchi & Halliday gen. nov., to accommodate a new species, P. montreuili Joharchi & Halliday sp. nov., from specimens collected on a rare earth-boring dung beetle species, Enoplotrupes bieti (Oberthür) (Coleoptera: Geotrupidae) in Nepal. The new genus differs from all other genera of Eviphididae by having an expansive anal shield. Other distinctive features of the new genus include the moderately narrow deutosternal groove with five rows of denticles, and the internal malae with thick and moderately long fimbriae.

Oral and Buccophryngeal Morphology of the Tadpoles of Polypedates maculatus with Notes on their Diet pattern

Oral morphological features and the diet of the tadpoles of Polypedates maculatus were described in this study. The tadpoles were collected from various water bodies of the state of Odisha over three consecutive breeding seasons (2018–2020). Oral and internal buccal characters were analysed independently for Gosner developmental stages 25 to 46. The upper labium has four labial tooth rows with a medial gap in the three rows proximal to the mouth, whereas the lower labium has three rows with a medial gap in the row proximal to the mouth. The order of length of denticle rows is A2>P1>P2>A1>P3>A3>A4 with a dental formula of A4(3)/P3(1). The food spectrum of the tadpoles included mostly phytoplanktons (represented by six classes and 51 genera) followed by zooplankton (two classes and four genera). Three Bacillariophyceae genera (Navicula, Pinnularia, and Synedra) contributed most of the gut contents. Scenedesmus was the major food items in Chlorophyceae family and had the highest numeric frequency (7.63%) among all the food items. Other prevalent food items included Zygnematophyceae, Cyanophyceae, Euglenophyceae, Rotifera, Ulvophyceae and Copepoda.

Deciphering the morphological variation and its ontogenetic dynamics in the Late Devonian conodont Icriodus alternatus

Identification of relevant taxonomic and evolutionary units is a recurrent issue in the fossil record, and all the more for ancient fossils devoid of modern equivalents such as conodonts. Extensive morphological variation has often led to the description of numerous species, subspecies or morphotypes, which may correspond to end-member morphologies reached through ontogeny. The platform elements of the Late Devonian conodont speciesIcriodus alternatuswere characterized by rows of denticles coming into occlusion between opposite elements; each element grew by the incremental addition of lamellae and by the addition of successive triads during ontogeny. During the late Frasnian and the early Famennian, the important morphological variation within this species led to the description of three subspecies. An extensive sample of early FamennianIcriodus alternatuswas quantified using 2D biometric measurements and denticle counts on 2D pictures, showing that the subspecies mainly differed in their size range but not in their general morphology. A 3D morphometric analysis was further performed on a subsample to characterize the shape of the ontogenetically older part of the elements. During ontogeny, early valleys between denticles tended to be filled, and the asymmetry between the inner and outer side of the element increased. These ontogenetic trends are responsible for the morphologies formerly described as the subspeciesIc. alt. mawsonaeandIc. alt. helmsi. Slight discrepancies between temporal ranges of the subspecies may be achieved through variations in range of size reached by the elements as a response to environmental changes. Disparity along ontogeny seems to follow an “hourglass model” suggesting a shift from relatively loose developmental constraints to a pattern of growth modulated by functional constraints during occlusion.

A new genus from Madagascar with strongly enlarged labium (Ephemeroptera, Baetidae)

A new genus of Baetidae, Megalabiopsgen. nov., and a new species, M. madagasikarasp. nov., are described from Madagascar based on nymphs. The new genus is characterized by having a strongly enlarged mentum; pedicelli with many long, stout, pointed setae; a brush of dense, short setae between prostheca and mola of both mandibles; an apically pointed maxillary palp with a stout seta at the tip; and a labium with many long, simple setae ventrally on glossae. The patellotibial suture is absent on the fore tibia and present on middle and hind tibiae. The claw is strongly elongated with two rows of denticles. The imago remains unknown and the relationships with other African genera of Baetidae are tentative. Despite being easily identifiable, only two nymphs were found in two highly sampled localities in Madagascar.

The anatomy of the palate in Early Triassic Chaohusaurus brevifemoralis (Reptilia: Ichthyosauriformes) based on digital reconstruction.

The palatal anatomy of ichthyosauriforms remains largely unknown. Here, the complete palate of the early-branching ichthyosauriform Chaohusaurus brevifemoralis is reconstructed and described for the first time with the assistance of high-resolution X-ray computed tomography (CT) scanning on the basis of the three-dimensionally preserved skull of its paratype (GMPKU-P-3086) from the Lower Triassic of South China. The reconstruction reveals new palatal features of C. brevifemoralis. The palatine contacts the jugal directly, which is observed in ichthyosauriforms for the first time. A single row of denticles is present on each side of the palate. The vomer exceeds the anterior and posterior margins of the internal naris. The pterygoid is posterior to the internal naris. The epipterygoid is present and the ectopterygoid is absent.

A new species of Caenis Stephens, 1835 (Ephemeroptera: Caenidae) from Tamil Nadu, Southern India.

A new mayfly species Caenis maduraiensis sp. nov. is described and illustrated from nymph and adults collected from lentic habitat around Madurai. The nymph can be distinguished by the following characters: anterior margin of labrum with row of bipectinate setae longer laterally and a group of highly fringed setae behind emargination; and hind claw long, slender and hooked with row of denticles. Adults are characterized by prosternal triangle with slightly concave sides, tip acutely pointed; apical part of forceps abruptly narrowed to the tip, with a long apical spine, and few trichomes on surface.

Influence of prey diet quality on predator-induced traits in wood frog tadpoles (Lithobates sylvaticus)

Abstract Diet quality and predation are two critical factors in determining the growth and development of organisms. Various anurans are susceptible to phenotypic changes influenced by these factors. Yet, few studies examined prey diet quality as potential influence over predator-induced traits. Using wood frog tadpoles (Lithobates sylvaticus) as a model species, we investigated the effects of three diet compositions (plant-based, animal-based, omnivorous) crossed with presence or absence of chemical cues from predatory dragonfly larvae (Aeshnidae). After 35 days, we recorded 11 morphological measurements, Gosner stage, and intestinal length of tadpoles to assess phenotypic changes under the six different experimental conditions. Our results showed the additive effects of both diet quality and predator chemical cue without detection of interactions between the two. Tadpoles receiving the omnivorous diet grew and developed faster with wider denticle rows than those receiving the plant or animal diets. The growth and development of tadpoles receiving only the animal diet were significantly hindered. These results emphasize the importance of diet quality in the growth and development of larval wood frogs. Chemical cues from predators significantly reduced tadpole body size but, in contrast to previous findings, did not affect tail size. Our experimental procedure of providing water containing predator and injured conspecific chemical cues on a weekly basis likely provided relatively weak predation risk perceived by tadpoles compared to previous studies using caged predators. The predator environment in our experiment, however, represents one ecologically relevant scenario in which predation risk is not urgent.

Philibaetis gen. nov., a new genus from the Philippines (Ephemeroptera, Baetidae)

Investigations of type material and new material from the Philippines (Luzon) revealed that Baetis luzonensis Müller-Liebenau, 1982 and B. realonae Müller-Liebenau, 1982 do not belong to Baetis Leach, 1815. A new genus, Philibaetisgen. nov., is described to accommodate both species and both are re-described based on larvae. The new genus is characterised by having a rectangular labrum with a submarginal row of long, simple setae on the dorsal surface and ventrally on lateral margins long, simple, spine-like setae, on anterolateral margins long, feathered setae and medially long, bifid setae and a partial, submarginal row of lanceolate setae. Both mandibles have blade-like incisors and dorsally, a mediolateral patch of long, spine-like setae; additionally, the left mandible has a tuft of long, partly branched setae at the base of the subtriangular process. Philibaetisgen. nov. is further characterised by a hypopharynx with a medial tuft of stout setae and anterolaterally, two smaller tufts of stout setae, a galea-lacinia with the distal denti-seta tooth-like and directed against canines, a fore femur apically with stout setae, both on anterior and posterior side and without a femoral patch and a claw with one row of denticles and two or three subapical setae. The protogonostyli under the cuticle of male last instar larvae are folded in the Labiobaetis type, excluding their affiliation to the genus Baetis. COI sequences were obtained from both species. The genetic distance (Kimura 2-parameter) between them is 17.5% on average. Very limited genetic distances of 0% to 3% (0.75% on average) were found between specimens of P. luzonensiscomb. nov.

Pedicelliops gen. nov., a new genus from West Africa with striking antennae (Ephemeroptera, Baetidae)

A new genus of Baetidae, Pedicelliopsgen. nov., and a new species, P. capillifersp. nov., are described from Guinea (West Africa) based on larvae. The new genus is characterized by having strongly enlarged pedicelli and very short flagella, a brush of dense, short setae between prostheca and mola of both mandibles, a small rectangular labrum, an apicolaterally pointed maxillary palp, a labial palp with a small distolateral protuberance and long setae ventrally on glossae and paraglossae. The femora of all legs are covered with numerous long, fine setae. The patellotibial suture is absent on the fore tibia and present on middle and hind tibiae. The claw is pointed with two rows of denticles. No spines are present on the posterior margins of the abdominal tergites. The imago remains unknown and the relationships with other African genera of Baetidae remains tentative. Despite being easily identifiable and of a fairly large size (body length ca. 5 mm), only two larvae were found in two highly sampled localities in West Africa.

Redescription of Apobaetis lakota McCafferty, 2000 (Ephemeroptera: Baetidae) and description of two new species from Brazil.

The genus Apobaetis Day is known by its small size and larval shifting-sand habitat preference (psammophilous). Three species of this genus are recorded in North America, from these, only Apobaetis lakota McCafferty needs to be redescribed because its original description is incomplete, turning difficult to distinguish it from species with similar morphology. Therefore, one of the objectives of this study is to redescribe A. lakota. Based on this redescription, two new species from Brazil, with similar morphology could be identified and are described (Apobaetis biancae sp. nov. and Apobaetis jacobusi sp. nov.). Apobaetis lakota can be differentiated by the labrum rectangular, distal margin without medial emargination, medial area of distal margin with three sockets of setae on dorsal surface; maxillary palp long, more than 2.0× the length of galea-lacinia, segment I with the same length as galea-lacinia; lingua subcircular with one medial lobe; glossa distally rounded; inner projection of labial palp segment II rounded and distally directed, segment III triangular; tarsal claws 1.3× the length of tarsus, without row of denticles. Apobaetis jacobusi sp. nov. can be differentiated from other species by fore tarsal claw I with the same length of tarsus, labrum medially with two protuberances and glossa with pointed apex. Apobaetis biancae sp. nov. can be differentiated by the absence of a ventral row of long thin setae near distolateral margin of labrum, four marginal spines on the paraproct, a subrectangular hypopharynx, and by the absence of robust setae on inner margin of the glossa.

Una nueva especie de alacrán del género Centruroides Marx (1890) (Scorpiones, Buthidae) de la depresión del Balsas, México

Se describe una nueva especie del género Centruroides Marx de la Depresión del Balsas en los Estados de Guerrero, Michoacán y México, en elevaciones que van de los 400 a los 1500 msnm. Esta especies se caracteriza por tener ocho hileras de dentículos en los dedos de la quela del pedipalpo y corresponde, dentro del género, a la sección de alacranes rayados, en la cual se le ha confundido con Centruroides limpidus limpidus Karsch y con Centruroides limpidus tecomanus Hoffmann. Las diferencias se observan en morfometría y patrón de coloración. Esta nueva especie es simpátrica con C. limpidus limpidus en la parte Este de su rango de distribución en el Estado de Michoacán y con C. infamatus infamatus Pocock en la Sierra de Coalcomán y regiones adyacentes en la parte Norte del Estado. Se registra también en una localidad en el Estado de Guerrero y en una localidad en el Estado de México.

New species of Thoonchus (Enoplida, Enchelidiidae) from the Yellow Sea and redescription of T. giganticus Belogurova et al., 1986.

The family Enchelidiidae is recovered as monophyletic and appears to be a more recently derived taxon within the superfamily Oncholaimoidea. It combines nematodes with buccal cavity with three unequal teeth, crenate pharynx, and absence of demanian system. Genus Thoonchus was erected for nematodes characterized by the large buccal cavity with heavily cuticularized walls and several rows of denticles, short and arcuate spicules and gubernaculums with expanded corpus. One new species is described here from the Sishili Bay, located in the northern Yellow Sea. Thoonchus covidus sp. nov. is characterized by the body length 3195‒4339 µm, outer labial and cephalic setae in one circle, pocket shaped amphid above the buccal cavity base, secretory-excretory pore at the base of cephalic setae, arched spicules, gubernaculum with thin proximal extension parallel to spicules, preanal supplement absent, three pairs of preanal papillae. It differs from other congeners by the position of secretory-excretory pore, absence of supplementary organ in males and presence of three pairs of precloacal papillae. Redescription of T. giganticus is also provided. After critical evaluation of the genus we recognize 4 valid species and provide a taxonomic key to species.

New genus and species of Baetidae (Insecta: Ephemeroptera) from Brazil.

One new taxon was brought to light during an Ephemeroptera survey in Roraima state, but it was not described. This new taxon was included in a cladistics analysis (as Gen A) in order to delimitate some Baetidae genera, and it was recovered as a new genus. Taking in account that the new genus and species status were already defined in a previously published paper, the objective of this study was to describe it based on imagoes and nymphs, and formally name it as Macuxi tunamore gen. nov. sp. nov. The new genus is sister group of Rhopyscelis Cruz, Salles Hamada + Varipes Lugo-Ortiz McCafferty clade, and can be differentiated from both mainly by the absence of long and stout setae on femora of all legs. Several characteristics were obtained in the morphological analyses to distinguish the new genus from other genera, but the paraglossa and glossa with pectinate setae, and claw with two rows of denticles, one reduced and other with apical ones larger than the others, are highlighted.

Erection of Euterranova n. gen. and Neoterranova n. gen. (Nematoda, Anisakidae), with the description of E. dentiduplicata n. sp. and new records of two other anisakid nematodes from sharks off New Caledonia.

Helminthological examinations of three species of sharks, Galeocerdo cuvier, Triaenodon obesus (both Carcharhinidae, Carcharhiniformes) and Stegostoma fasciatum (Stegostomatidae, Orectolobiformes) from New Caledonian waters, carried out during 2003–2005, revealed the presence of three species of adult anisakid nematodes referable to Terranova Leiper et Atkinson, 1914. However, this genus can no longer be considered valid, because its type species has been designated a species inquirenda. Therefore, the present nematodes are assigned to two newly established genera, Euterranova n. gen. [type species E. dentiduplicata n. sp.] and Neoterranova n. gen. [type species N. scoliodontis (Baylis, 1931) n. comb.], based mainly on different labial structures. Euterranova dentiduplicata n. sp. from the stomach of S. fasciatum is mainly characterized by the presence of lips with two rows of denticles. Innominate specimens of Euterranova (a female and a third-stage larva) were collected from the digestive tract of T. obesus. Specimens of N. scoliodontis were recorded from G. cuvier. The two named species are described based on light and scanning electron microscopical examinations. Neoterranova scoliodontis has previously been recorded in New Caledonian waters from the same host species. Species previously attributed to Terranova are transferred to Euterranova (5 species), Neoterranova (4 species) or considered species inquirendae (10 species). Since Pseudoterranova Mozgovoy, 1950 was found to be a nomen nudum according to the International Code of Zoological Nomenclature (ICZN), the available name of this genus is Pseudoterranova Mozgovoy, 1953. A key to Porrocaecum-like nematode genera (Porrocaecum, Pseudoterranova, Pulchrascaris, Euterranova, and Neoterranova) is provided.

High resolution XCT scanning reveals complex morphology of gnathal elements in an Early Devonian arthrodire

Arthodire placoderms, as a possible sister group of Chinese ‘maxillate’ placoderms plus crown gnathostomes, provide important information regarding early evolution of jaws and teeth. High-resolution computed tomography and digital dissection on a unique articulated 400 million-year-old buchanosteid arthrodire permitsa detailed description of the three types of gnathal elements in basal arthrodires for the first time, giving insights into their morphology and the organization of the associated dentition. In displaying numerous denticle rows (dental fields), the gnathal element morphology is very different from the much-reduced denticulation of higher brachythoracid arthrodires, even though the latter have been used recently to interpret origin and early evolution of teeth. Ossification centres are anterolateral on the anterior supragnathal (attached to the braincase), anteromesial on the posterior supragnathal (attached to the palatoquadrate), and in the central part of the biting portion of the infragnathal (attached to the meckelian cartilage). The latter bone shows no evidence of two ossification centres as has been interpreted for more advanced arthrodires. Denticle rows radiating from the ossification centre form dental fields in all three elements, and are more similar to the gnathal elements of phlyctaeniid and actinolepid arthrodires than to advanced brachythoracids. The new evidence gives insights into the primitive arthrodire condition for comparison with the dermal jaw bones of Chinese ‘maxillate’ placoderms that have been homologised with the premaxilla, maxilla, and dentary of osteichthyans. The new details will help clarify the sequence of character acquisition in the evolution of marginal jaw bones in basal gnathostome groups.

A scanning electron microscopy study of Anisakis physeteris molecularly identified: from third stage larvae from fish to fourth stage larvae obtained in vitro

The development of the fourth larval stage (L4) of Anisakis physeteris was studied using scanning electron microscopy (SEM), comparing it with third larval stage (L3) recently obtained from the host fish, blue whiting (Micromesistius poutassou), from the western Mediterranean Sea (east coast of Spain, zone FAO 37.1.1). After molting to L4, samples of the parasite were examined at different times in order to observe their development. Following collection of the L4, a small portion was taken from the middle of the larva for molecular identification, confirming in all cases that it was A. physeteris. The anterior and posterior sections of the larvae were prepared for morphological study by SEM. The development of a row of denticles on each of the three prominent lips, almost reaching the buccal commisures, was observed in the L4. Pores of unknown function were found in the upper external part of each lip. Clearly developed cephalic papillae, amphids, and deirids were also observed in L4, while, although present in L3, these were beneath the cuticle. Phasmids were detected in L4 but not in L3. The L4 tail finished in a conical lobe with a blunt point, absent in L3. In the oldest L4, some preanal papillae were observed beneath the cuticle in males, while, in females, the vulva could be seen by light microscopy, apparently still covered by the cuticle.