Dorsal Sculpture Research Articles

Milnesium guanyinensis sp. nov. (Eutardigrada: Apochela) from Yunnan, China

A new species from China, Milnesium guanyinensis sp. nov. (Tardigrada: Eutardigrada: Apochela: Milnesiidae), is described by means of classical taxonomic analysis, i.e. morphology-based evidence, specifically obtained from light and scanning electron microscopy imaging. The new Milnesium species is characterised by the reticulated dorsal cuticle and a claw configuration [2-2]-[2-2] in hatchlings and [2-3]-[3-2] in juvenile and adult specimens. Milnesium guanyinensis sp. nov. is most similar to M. katarzynae Kaczmarek et al. 2004 and M. pacificum Sugiura et al. 2020, but it differs from them mainly by details of the dorsal sculpture and some morphometric characters. So far, there have been nearly 200 Tardigrada species reported for China, and the discovery of the new species raises the number of first known tardigrade species of the genus Milnesium in China to three.

New Indomalayan Nebularmis species (Heterotardigrada: Echiniscidae) provoke a discussion on its intrageneric diversity

Recent years have brought undeniable progress in tardigrade taxonomy, and speciose complexes were detected in a number of phylogenetic lineages. The family Echiniscidae is one such lineage; it is one of the most diverse groups of limno-terrestrial tardigrades and can be characterized as having achieved great evolutionary success. In this contribution, using populations representing several species that originated from the Indomalayan region, we reconstructed phylogenetic affinities within Nebularmis, a recently erected genus within the Echiniscus lineage. Nebularmis auratussp. nov. and Nebularmis burmensissp. nov. are described from the Eastern Yoma Mountains and the Shan Hills (Myanmar), Nebularmis bhutanensissp. nov. is described from the Eastern Himalayas (Bhutan), and Nebularmis indicussp. nov. is described from the foothills of the Western Ghats (Goa, India). Moreover, males are reported in populations of the last two species. All known members of the genus can be phenotypically differentiated based on minute details of their dorsal sculpture and claws. Moreover, a very wide tropical distribution is demonstrated for Nebularmis cirinoi, recorded for the first time from islands of the Malay Archipelago. Furthemore, novel morphological, genetic, and geographic data allowed for the clarification of the generic diagnosis. Currently available data favor a scenario under which Nebularmis evolved in Southeast Asia and later dispersed to other regions of the globe.

Integrative description of five Pseudechiniscus species (Heterotardigrada: Echiniscidae: the suillus-facettalis complex).

Pseudechiniscus is a morphologically homogeneous heterotardigrade genus with a relatively low number of morphological features useful for the species discrimination. The species of the Pseudechiniscus suillus-facettalis complex are some of the most challenging tardigrades to identify. Here, we examine several populations from Antarctica, Italy, Madagascar and Norway that would have most likely been attributed to Pse. suillus prior to the recent redescription of the species. Populations were analysed using integrative taxonomy-a combination of classical morphology and morphometry, as well as genetic data. Besides minute differences in dorsal sculpture and morphometry, we found clear, species-specific differences in ventral sculpture which are very useful in discrimination of Pseudechiniscus species. Based on morphology (mainly ventral sculpture) and significant genetic distances in COI and ITS-2 sequences, we describe five new species: Pse. angelusalas sp. nov. from Madagascar, Pse. dastychi sp. nov. from Antarctica, Pse. ehrenbergi sp. nov. from Italy as well as Pse. indistinctus sp. nov. and Pse. lacyformis sp. nov. from Norway. Finally, we provide an updated phylogenetic tree of the genus Pseudechiniscus based on COI sequences.

High diversity in the Pseudechiniscus suillus–facettalis complex (Heterotardigrada: Echiniscidae) with remarks on the morphology of the genus Pseudechiniscus

AbstractPseudechiniscus is a morphologically homogeneous genus of tardigrades. The morphological features commonly used for species discrimination in this genus are the dorsal sculpture, the shape and number of dorsal plates and trunk appendages. Species of the Pseudechiniscus suillus–facettalis complex are one of the most challenging tardigrades to identify. All species are similar in their general appearance and all lack trunk appendages. Moreover, not only the nominal Pseudechiniscus suillus, but also other members of the suillus–facettalis complex have been insufficiently described. In our study, we examined several populations from the Northern and the Southern Hemispheres that could be traditionally attributed to Pse. suillus. These populations were analysed using integrative taxonomy – a combination of classical morphology and morphometry with molecular data. Besides the differences in the dorsal sculpture and morphometry, we also found species-specific differences in ventral sculpture, which were originally used for discrimination of Pseudechiniscus species. Moreover, we provide an extensive discussion on all morphological and morphometric differences used in Pseudechiniscus taxonomy and indicate main taxonomic problems with this genus. Finally, we redescribe the nominal Pse. suillus from Italy.

Marine Tardigrada from the Mexican Caribbean with the description of Styraconyx robertoi sp. nov. (Arthrotardigrada: Styraconyxidae).

Marine tardigrades were sampled at three sites on Mexico's Caribbean coast. Eleven taxa were collected, one of which is described as a new species. Styraconyx robertoi sp. nov. is characterized by: asymmetric primary clavae; dorsal cuticle with a grid-like sculpture; claws with reduced accessory hooks; females with peduncles on only two digits (the external) of legs I-IV; males with peduncles only on the external digits of legs I-III and peduncles on all four digits of leg IV. Styraconyx robertoi sp. nov. is most similar toS.craticuliformis Chang Rho, 1998 and S. kristenseni Renaud-Mornant, 1981 by having asymmetric primary clavae but differs from S. craticuliformis mainly by the number of peduncles and from S. kristenseni mainly by the presence of a grid-like dorsal sculpture. Additionally, a comparison of material collected from the same region, but reported previously only as genus level records, was carried out in order to produce a refined list of the known Mexican marine tardigrade species.

Variability of Echiniscus tristis Gąsiorek & Kristensen, 2018-is morphology sufficient for taxonomic differentiation of Echiniscidae?

The majority of species in the genus Echiniscus (Heterotardigrada) have been described based on differences in the chaetotaxy or dorsal sculpture. Dorsal sculpture is, in general, considered to be species-specific and not very variable; however, many problems have arisen due to various interpretations of microscope images, which has led to taxonomic confusion in the genus Echiniscus. Conversely, chaetotaxy is generally much easier to interpret, even using low-quality microscope optics. In this study, we emended the description of Madagascan population of Echiniscus tristis Gąsiorek & Kristensen, 2018 that exhibits several different types of chaetotaxy and dorsal sculpture. The analysed specimens were characterised by two types of chaetotaxy, A-C-Dd-E and A-Dd-E, but we also found a wide range of variation in appendage number, shape and length. The observed differences are partly correlated with life stages. Additionally, we analysed DNA sequences of 28S rRNA, ITS-2 and COI of the two main morphotypes, and did not find significant genetic differentiation of the two morphotypes. This highlights the importance of analysing the morphology of both immature stages and adults, as well as of DNA markers in tardigrade species identification.

Current knowledge on Mexican tardigrades with a description ofMilnesium cassandrae sp. nov. (Eutardigrada: Milnesiidae) and discussion onthe taxonomic value of dorsal pseudoplates in the genus Milnesium Doyère, 1840.

Mexico is a megadiverse country, however its tardigrade fauna is poorly known and to date 44 species have been reported from this region. In the present paper, an update of the reported Mexican tardigrades is presented, increasing the number of recorded tardigrades to 55 species (11 new records). Moreover, we describe Milnesium cassandrae sp. nov. from State of Nuevo León in northern Mexico. The new species is most similar to Mil. krzysztofi Kaczmarek Michalczyk, 2007 and Mil. beasleyi Kaczmarek, Jakubowska Michalczyk, 2012, but it differs from them mainly by details of the dorsal sculpture and some morphometric characters. We also discuss the taxonomic value of a recently described feature, 'pseudoplates', for differentiating the taxa within the genus Milnesium Doyère, 1840. [Zoobank URL: urn:lsid:zoobank.org:act:0684AE18-0510-4F7B-B75D-AE5177FBF2A2].

Cornuproetine (proetide) trilobites with nine thorax segments from the Devonian of Morocco, Germany and the Czech Republic

The majority of cornuproetine taxa known from articulated specimens have ten thoracic segments. Here we record rare, well-preserved specimens with nine segments in the Early and Middle Devonian of Morocco, Germany and the Czech Republic. These encompass the genera Lepidoproetus Erben, Sculptoproetus Erben, Macroblepharum Alberti, Koneprusites Přibyl, Paralepidoproetus Alberti, Timsaloproetus Gibb and Chatterton and Hollandiella gen. nov. Large holaspides of these trilobites are often comparatively small and bear dorsal sculpture consisting of terrace lines in a fingerprint-like configuration, small granules, or a mixture of these features. The holotype of Sculptoproetus sculptus (Barrande) and the lectotype of Lepidoproetus lepidus (Barrande), the type species of these genera, are refigured. Additional topotypical specimens of S. sculptus are illustrated; these provide new insights into the morphology of this species, leading to the putative synonymy of Macroblepharum with Sculptoproetus. The following new cornuproetine taxa are described: Hollandiella curvirostris gen. et sp. nov., Hollandiella lebruni gen. et sp. nov., Hollandiella verecunda gen. et sp. nov., Koneprusites oresibios sp. nov., Lepidoproetus arenicolus sp. nov., Sculptoproetus raki sp. nov., Timsaloproetus weddigei sp. nov., Timsaloproetus gibbae sp. nov., Timsaloproetus pulchistriatus pulchistriatus ssp. nov. and Timsaloproetus pulchistriatus repens ssp. nov. Timsaloproetus haasi is recorded from several localities in Morocco. Additionally, Tafilaltaspis rufa sp. nov. is proposed as a new species of the nine-segmented eremiproetine Tafilaltaspis, which was traditionally classified as a cornuproetine genus.

Echiniscus siticulosus (Echiniscidae: spinulosus group), a new tardigrade from Western Australian scrub

ABSTRACTAustralian fauna is widely recognised for its high levels of endemism, and tardigrade fauna does not seem to be an exception in this respect. The richness of xerothermic habitats in Australia, often occupied by heterotardigrade family Echiniscidae, entails high abundance and uniqueness of echiniscid assemblages. A new gonochoristic/dioecious echiniscid species was found in large numbers in samples from Western Australia. Echiniscus siticulosus sp. nov., characterised by dominant large cuticular pores in the dorsal sculpture and appendages in the form of spines, represents the spinulosus group but can be distinguished from the known members of this species complex by a unique combination of traits: peculiar faceting of the caudal plate formed by ridge-shaped epicuticular extensions and pore morphology. An amended phenotypic diagnosis of Echiniscus spiniger Richters 1904, the species morphologically most similar to the new species, is also presented.

A new species of Astacilla (Crustacea: Isopoda: Valvifera) from the Le Danois Bank (N Spain, NE Atlantic), living on Placogorgia sp. (Cnidaria: Octocorallia) with notes on the cnidarian host

Located in the Cantabrian Sea (NE Atlantic), El Cachucho is the largest offshore Marine Protected Area (MPA) in Spain. One of the most abundant keystone megafauna species occurring in this MPA is a yellow gorgonian of genus Placogorgia Wright and Studer (1889), occurring in relatively high densities in steep slopes with rocky outcrops at depths ranging 500–1200 m. Here, we describe a new species of isopod, Astacilla andresmeixidei sp. nov., living in association with a specimen of a yellow gorgonian collected at 525 m depth. Females of the new species are characterised by a trapezoidal pereonite 4 with a middorsal bifurcate tubercle on posterior margin; males have a rectangular pereonite 4 with small tubercles irregularly distributed and pereonite 3 with a midventral process. The new species is distinguished from the most morphologically similar species Astacilla gorgonophila Monod (1925) by its dorsal sculpture, having a shorter antenna 2 with a flagellum of three articles plus a claw, and also by its geographic and bathymetric distribution. Phylogenetic analysis using the mitochondrial marker COI confirmed that the new isopod is a member of the family Arcturidae and placed it in a clade, recovered with low support, including other species of the genus Astacilla Cordiner, 1793. As with other previously described arcturids, we suggest that A. andresmeixidei sp. nov. is a commensal of the gorgonian using its branches to reach higher in the water column and thus increase its chances to get more particulate organic matter. Our morphological analyses on the gorgonian host, suggest that it belongs to the genus Placogorgia although in our phylogenetic results using the nuclear marker msh1 the gorgonian shows affinities with the genus Paramuricea Kölliker (1865). This taxonomic inconsistency is discussed.

New Species and New Records of the Weevil Genus Ceutorhynchus Germar (Coleoptera, Curculionidae) from the U.S.A.

Ceutorhynchus balciunasisp. n., closely related to the Eastern Siberian and Far Eastern C. matisi Korotyaev, is described from Oregon and California. Ceutorhynchus fallisp. n. from Alaska (Nome) is related to these two species but differs from both in a set of morphological characters typical of the Arctic and alpine weevils and may be considered a truly Arctic form. Ceutorhynchus ? kolymensis Kor., a species very close to the mostly Western Palaearctic pair of species with characteristic coarse dorsal sculpture, C. puncticollis Boh. and C. talickyi Kor., is recorded from the Rocky Mountains in Colorado (U.S.A). Ceutorhyncuis barkalovi Kor., a circumpolar species previously known in North America only from Yukon (Canada) is also recorded from the Rocky Mountains in Colorado (U.S.A). New state records of Ceutorhynchus moznettei Fall and C. downiei Colonnelli are given.

The genus Milnesium (Eutardigrada: Milnesiidae) in the Sierra Nevada de Santa Marta (Colombia), with the description of Milnesium kogui sp. nov.

A new species, Milnesium kogui sp. nov. is described from the Sierra Nevada de Santa Marta, Colombia. The new species belongs to the tardigradum group and is most similar, by the claw configuration [2-2]-[2-2], to Milnesium dujiangensis and Milnesium katarzynae. Milnesium kogui sp. nov. differs from M. dujiangensis mainly by the presence of primary branches on all legs and from M. katarzynae by the absence of dorsal sculpture. Additionally, in this paper we present a list of all Milnesium species recorded in Colombia including Milnesium cf. barbadosense Meyer & Hinton, 2012 and M. brachyungue Binda & Pilato, 1990, new additions to the recorded fauna of Colombia.

The genus Milnesium Doyère, 1840 (Tardigrada) in South America with descriptions of two new species from Argentina and discussion of the feeding behaviour in the family Milnesiidae.

The diversity and distribution of the tardigrades in South America are rather poor and selective, as is information about their feeding behaviour and diet. To date, only ca. 210 tardigrade taxa have been reported from the region of South America. In the present paper, we provide an update of the distribution of the genus Milnesium inSouth America and discuss some aspects of the feeding behaviour in the family Milnesiidae. In seven moss samples collected in the Argentinean province of Río Negro, 31 specimens, 4 exuviae and 32 eggs belonging to the genus Milnesium were found. Among them, four species were identified: Milnesium argentinum sp. nov., Milnesium beatae sp. nov., Milnesium brachyungue and Milnesium granulatum. By its dorsal sculpture,M.argentinum sp.nov. is most similar to M.beatae sp.nov., Milnesiumbeasleyi andMilnesiumberladnicorum, butit differs from M.beasleyi andM.berladnicorum mainlyby having a different claw configuration and from M. beatae and M. beasleyi by having stylet supports inserted in a more caudal position and by some other morphometriccharacters. In the width of its buccal tube and the claw configuration [3-3]-[3-3], M.beatae sp.nov. is most similar to Milnesiumbohleberi,M.brachyungue andMilnesiumeurystomum,but it differs from them mainly by having a sculptured dorsal cuticle and by some other morphometric characters. The study discusses distribution and taxonomic problems of the Milnesium species known from South America. As of now, nine Milnesium taxa are known from this region (including two new species reported in this paper). Additionally, the study broadens our knowledge of tardigrades' feeding behaviour, provides some details about their diet and suggests that the type of prey chosen by some species belonging to the family Milnesiidae may be associated with the width of their buccal tube.

Two flat-backed polydesmidan millipedes from the Miocene Chiapas-amber Lagerstätte, Mexico.

Two species of fossil polydesmidan millipedes (Diplopoda: Polydesmida) embedded in amber are described from Miocene strata near Simojovel, in the Chiapas Highlands, Mexico. Maatidesmus paachtun gen. et sp. nov., placed into Chelodesmidae Cook, 1895, and Anbarrhacus adamantis gen. et sp. nov., assigned in the family Platyrhacidae Pocock, 1895. Morphological data from fossil specimens have been recovered using 3D X-ray micro-computed tomography and regular to infrared-reflected microscopy. Both fossil species are recognizable as new primarily but not exclusively, by collum margin modification and remarkable paranotal and metatergite dorsal sculpture.

Milnesium berladnicorum sp. n. (Eutardigrada, Apochela, Milnesiidae), a new species of water bear from Romania.

In a lichen sample collected from a tree in Bârlad town (Vaslui County, Romania), a new tardigrade species belonging to the genus Milnesium (granulatum group) was found. Milnesium berladnicorum sp. n. is most similar (in the type of dorsal sculpture) to Milnesium beasleyi Kaczmarek et al., 2012 but differs from it mainly by having a different claw configuration and some morphometric characters. Additionally, the new species differs from other congeners of the granulatum group by the different type of dorsal sculpture, claw configuration and some morphometric characters.

Loricaseius lepontinus gen. nov., sp. nov., a new genus and species of eviphidid mite from the Italian Alps (Acari: Mesostigmata), with an updated key to European genera of the family Eviphididae.

A new monotypic genus and a new free-living edaphic species of the family Eviphididae, Loricaseius lepontinus gen. nov., sp. nov., are described on the basis of adults and deutonymphs collected from litter detritus in the Italian Lepontine Alps (Piemonte, Val d'Ossola). The new genus is characterized by a widened and truncate idiosomal vertex with widely spaced setae j2, peritrematal shields extensively expanded laterally in adult stages, narrowed intercoxal region, tarsus I dorsally concave, and strong sexual dimorphism of some secondary sexual characters (dorsal sculpture, posteroventral sclerotization of soft integument, shape of anal shield, opisthogastric and posterodorsal chaetotaxy). Also, the female's anal shield is surrounded by a large area of strongly sclerotized skin that resembles a ventri-anal shield, with well-developed anterolateral extensions projecting between the dorsal and peritrematal shields, and posteriorly and laterally fused with the dorsal shield. We show that this may be an unusual type of age-related secondary sclerotization unknown in the family. An updated key to European genera of the family is presented.

Tardigrades from Peru (South America), with descriptions of three new species of Parachela.

In four samples of mosses and mosses mixed with lichens collected in the Peruvian region of Cusco, 344 tardigrades, 78 free-laid eggs and six simplexes were found. In total, nine species were identified: Cornechiniscus lobatus, Echiniscus dariae, E. ollantaytamboensis, Isohypsibius condorcanquii sp. nov., Macrobiotus pisacensis sp. nov., Milnesium krzysztofi, Minibiotus intermedius, Paramacrobiotus intii sp. nov. and Pseudechiniscus ramazzottii ramazzottii. Isohypsibius condorcanquii sp. nov. is most similar to I. baldii, but differs mainly by the absence of ventral sculpture, the presence of the oral cavity armature, a different macroplacoid length sequence and a different shape of macroplacoids. The new species also differs from other congeners by a different dorsal sculpture, the absence of cuticular bars under the claws and the absence of eyes. Macrobiotus pisacensis sp. nov. differs from the most similar M. ariekammensis and M. kirghizicus by a different oral cavity armature, the presence of cuticular pores, details of egg morphology and some morphometric characters of both animals and eggs. Paramacrobiotus intii sp. nov. differs from most similar species of the genus by a different type of the oral cavity armature, details of egg morphology and some morphometric characters of both animals and eggs. In addition, we briefly discuss the tardigrade fauna of Peru, and propose a simple and economic system of describing relative lengths of pharyngeal macroplacoids. The system is especially useful in interspecific comparisons and differential diagnoses.

Hypocaccus (Baeckmanniolus) laevis Thérond, 1963 is not synonymous withH. (B.) virescens Thérond, 1963 (Coleoptera: Histeridae: Saprininae).

The synonymy of Hypocaccus (Baeckmanniolus) virescens Thérond, 1963 and Hypocaccus (Baeckmanniolus) laevis Thérond, 1963 is rejected following the examination of the type specimens of both species. Hypocaccus (Baeckmanniolus) laevis stat. restit. is reinstated as valid. The two species differ mainly in the dorsal sculpture, pronotal shape, shape of protibia as well as in other minor characters. Hypocaccus (B.) laevis is newly recorded from Kenya.

The genus Limnoria (Limnoriidae, Isopoda, Crustacea) in Europe, including a key to species

A new species of Limnoria inhabiting seaweed from the Alborán Island (western Mediterranean) is described. This is the seventh record of the genus from European coasts. L. turae n. sp. is mainly distinguished by the unique dorsal sculpture of its pleotelson, with 3 pairs of longitudinal carina without puncta, and the absence of the mandibular rasp. L. carinata is redescribed from a neotype. A key to European species is provided, and two comparative tables of the European species are included.

Coulmannia rossensis sp. n. (Isopoda, Asellota, Paramunnidae) from the Ross Sea, Southern Ocean

A new species of Coulmannia, Coulmannia rossensis, is described from the Ross Sea, Antarctica. It is most similar to Coulmannia ramosae Castelló, 2004, but can easily be distinguished from this species bythe males yielding a pair of granulate humps on the dorsum of the pereonites 1–6 and a single granulate hump on the pereonite 7 and the free pleonite. Coulmannia rossensis sp. n. is sexually dimorphic. The dorsal sculpture of the female bodies yield a single granulate hump on all the pereonites and free pleonite. The species of the genus Coulmannia are restricted to the Southern Ocean, and Coulmannia rossensis sp. n. is the fourth species included in it.