Valve Margin Research Articles

Ulnariashun-biseriata sp. nov. (Bacillariophyta) from the Shun River in Hunan Province, China.

A new species, Ulnariashun-biseriata sp. nov., was found in the Shun River of Hunan Province, southern China, and its morphology was described based on light and scannning electron microscope obervations. Ulnariashun-biseriata is characterized by its lanceolate valve outline, apiculate valve apices, slightly undulate valve margins, mostly biseriate striae, variable central area, and closed valvocopula. Many abnormal valves of U.shun-biseriata were observed in the samples investigated and the most frequent morphological abnormalities consisted of a lack of symmetry relative to the apical axis caused by a unilateral expansion in the middle part of the valve.

Investigation of the distribution patterns in moinids (Crustacea: Cladocera: Moinidae) forming ephippia with two resting eggs

During last two decades, morphological and genetic studies of the microcrustaceans from the family Moinidae Goulden, 1968 (Crustacea: Branchiopoda: Cladocera) were intensified. However, species diversity within this family remains underestimated. It refers to both subtropical and tropical areas of different continents that have traditionally been less studied compared with Central Europe and some other Palaearctic regions. In addition to this, only a restricted set of morphological characteristics is used for the discrimination of species within the genus Moina Baird, 1850. Most common moinid taxa are considered species complexes rather than single species, making any biogeographic reconstruction difficult. Here, we present an investigation of distribution patterns in moinids that form ephippia with two resting eggs based on both a reexamination of data from the literature and from specimens in museum and personal collections. Also, we redescribed morphology of poorly known taxa from the arid regions of the Old World—Moina belli Gurney, 1904 and M. kaszabi Forró, 1988 and clarify their diagnostic morphological characters and distributional ranges. We found that M. belli and M. kaszabi are morphologically very similar. In both species, setae 1 and 2 of thoracic limb I are armed bilaterally by fine, densely located short setulae. Reliable differences between M. belli and M. kaszabi concern armature of the valve posteroventral portion. Among the moinids with two resting eggs in the ephippium, M. belli and M. kaszabi are morphologically closer to M. macrocopa (Straus, 1820) and M. americana Goulden, 1968. All these species have: (1) a dorsal head pore; (2) fine long hairs on head, valve and preanal margin of postabdomen; (3) thoracic limb I of male with a long exopodite. In general, an investigated group of moinids includes both species with relatively compact and very broad distributional ranges. We concluded that maximum diversity of the moinids forming ephippia with two resting eggs is characteristic of southern portions of Palaearctic and Nearctic zoogeographical regions and approximately corresponds to subtropical climate zone. We need to underline that M. macrocopa and M. americana have a great invasive potential. Both species were anthropogenically introduced in South America and have been successfully naturalized there. Their distribution in tropical regions of the Old World and Australia requires new precise investigations. A group of moinids forming ephippia with two resting eggs can be considered as a convenient model for biogeographical reconstructions, including studies on changes in aquatic ecosystems due to global climate warming, eutrophication and the introduction of non-native species. There is no doubt that subsequent joint application of morphological and genetic data will shed more light on the global phylogeographic structure of the entire family Moinidae.

Cryptic fauna in abandoned bivalve shells and taphonomy of bivalve steinkerns in the Late Ordovician of Baltica

ABSTRACT The encrusted bivalve steinkerns in the Upper Ordovician of Estonia suggest that the rapid sea-floor cementation facilitated the early lithification of the sediment within the bivalve shell and the shell valves, likely aragonitic in composition, were dissolved due to calcite sea conditions similarly to many other regions in the Ordovician. The abandoned bivalve shells contained cryptic invertebrates. The coelobite fauna was dominated by encrusting brachiopods, followed by bryozoans and cornulitids. The bryozoans and cornulitids do not prefer specific regions of the shell interior, indicating that the waters within the shell were sufficiently nutrient-rich throughout. Encrusting brachiopods are always confined to valve margins, suggesting that the waters were nutrient-rich enough for the brachiopods only at the edge of the outer environment. Thus, it is possible that bryozoans and cornulitids were better adapted for a cryptic life than the encrusting brachiopods in the Late Ordovician of Estonia.

Geissleria triundulata sp.nov., a new freshwater diatom (Cymbellaceae, Bacillariophyta) from the Mula-Mutha River Basin, India

While conducting a seasonal assessment of the Mula-Mutha River basin in Maharashtra, India, an unknown taxon of the genus Geissleria was observed from an oligotrophic stream connected to the Mutha River. This taxon is described here as new to science based on detailed light and scanning electron microscopic observations. The characteristics of this new species used to assign it to the genus Geissleria include triundulate valve margins, a straight and filiform raphe structure, lineolate striae, and the presence of annuli a circular or semi-circular hyaline area positioned on the valve apices. In G. triundulata sp. nov., the annulus is barely visible in light microscopy. The present study discusses the morphology of this new species compared to other Geissleria species, undertaking a thorough analysis of various morphological features observed in members of the genus Geissleria. This new taxon resembles G. lubilensis and G. fogedii in having a slightly triundulate margin but differs in their broad and protracted valve apices, holding differences from the new species. This study also presents a brief discussion concerning the ecology of the newly discovered species and the worldwide distribution of all Geissleria species.

A new freshwater species Achnanthes licunese sp. nov. (Achnanthaceae, Bacillariophyta) from pebbles of Licun River, Shandong Province, China

A new freshwater diatom species, Achnanthes licunese sp. nov., was found on pebble samples collected from Licun River in Shandong Province, China. The various taxonomic characteristics of Achnanthes licunese sp. nov. is observed under light and scanning electron microscope. The living cells of A. licunese sp. nov. possesses two chloroplasts. Its valves exhibit a linear to linear-lanceolate outline, slightly constricted in the middle part, with uniseriate striae. The central area of the raphid valves is expanded into a linear and thickened stauros, and the raphe is filiform. On the araphid valves, there is no central area, and the axial area (sternum) is located in the valve margin. The valve of the A. licunese sp. nov. possesses the marginal spines, but no marginal ridge and terminal orbiculi. By comparing the new species with similar Achnanthes species, A. licunese sp. nov. was confirmed to be sufficiently different regarding valve size, striae density, and the presence of marginal spines. The discovery of this species increases the diversity of freshwater diatoms.

Cymbella liangyanlingii sp. nov. (Bacillariophyta, Cymbellaceae), a new diatom species from the upper tributary of Liujiang River, Guangxi Zhuang Autonomous Region, China

Cymbella liangyanlingii sp. nov. was collected from epilithic samples in the Liujiang River, Guangxi Zhuang Autonomous Region, China. Light microscopy (LM) and scanning electron microscopy (SEM) were used to describe the morphology of the new species, and in addition we provided detailed ecological information about this species. C. liangyanlingii sp. nov. has the features that assign it to the genus Cymbella, including the terminal raphe fissures deflected toward dorsal margin, apical pore fields present at each end on the valve and, for most taxa in the genus, one or more stigmata on the ventral side of the central area. The key diagnostic features that easily distinguish the new species from other similar species: 1) the inconspicuous central area, 2) three slit-like stigmata on the ventral margin, 3) the striae have no interruption on the valve margin, and 4) striae that are mostly uniseriate in the middle and biseriate (5–7) in the ends. This combination of features distinguishes C. liangyanlingii sp. nov. from congers such as C. liyangensis, C. distalebiseriata, C. alexandrovichii and C. hubeiensis. These findings can help us further understand the morphological and ecological information of the genus Cymbella in China.

Three New Nitzschia (Bacillariophyceae) Species from Highly Acidic Artificial Lakes in Çanakkale, Türkiye

Çanakkale is located in Western Anatolia, a region known for extensive mining in the country. In this study, three new species: Nitzschia arslaniana sp. nov., Nitzschia efeiana sp. nov., and Nitzschia szaboiana sp. nov. are described from highly acidic environments in Çanakkale. In morphology, Nitzschia arslaniana is similar to Nitzschia inconspicua but Nitzschia inconspicua is broader, with a lower fibulae density. Nitzschia efeiana is similar to Nitzschia. bremensis, Nitzschia capitellata, Nitzschia homburgiensis, Nitzschia hybrida, Nitzschia palustris, and Nitzschia pellucida. However, Nitzschia efeiana has variable fibulae widths, thickened virgae on its external valve face, and an elevated ridge on the valve margin opposite the keel. Nitzschia szaboiana is similar to Nitzschia pusilla, but the later taxon has a higher striae density. This study highlights the unique species diversity of extreme environments, including anthropogenic extreme environments, by describing three new taxa in the same genus.

Myxobolus coriumicus n.sp. (Cnidaria: Myxozoa) Causing Scale Disease Associated with Skin Lesions in Indian Cultured Carp, Cirrhinus mrigala in Punjab.

The motive of the present study was to investigate incidences of myxozoan parasite infection in commercially important fishes and their characterization using morphological attributes and molecular approach. The specimens of cultured Cirrhinus mrigala were sampled and various organs were examined. The plasmodia were detected on the scales. The identification of species was based on the myxospore morphology and 18S rDNA sequence analyses. For phylogenetic analysis, maximum likelihood (ML) and Bayesian inference (BI) methods were employed. The SEM and histological studies were performed to assess the damage to the scales. The infected fishes had white patches on the scales and red haemorrhagic lesions on the skin. The plasmodia of Myxobolus coriumicus n. sp. were located on the dorsal surface of the scale towards its exposed part. SEM study indicated that lepidonts were damaged in the infected scales. The myxospores were spherical in shape, 9.0-10.0 × 8.0-9.0[Formula: see text]m in size, with two ovoid equal polar capsules 3.13-4.0 × 2.03-2.33[Formula: see text]m in size, having 4-5 sutural edge markings at the posterior-lateral margins of the shell valves and binucleated sporoplasm. BLAST search based on 18S rDNA revealed 93.87% sequence similarity with M. rewensis, (MZ230381). The prevalence of infection was 6.3% and Scale Plasmodium Index (SPI) was 3 indicating heavy infection. Morpho-molecular data generated during this study enables us to conclude that the present species, M. coriumicus n. sp. infecting scales of C. mrigala is new to the science causing significant damage to the scales.

GENOME-WIDE ANALYSES OF CORE REGULATORY MODULE SHATTERING CASCADE GENES IN CANOLA (BRASSICA NAPUS L.)

Premature seed shattering in canola causes massive losses in yield by up to 50% in adverse climatic conditions. In the model plant Arabidopsis thaliana, which belongs to the same family as canola, the Brassicaceae, eight genes participate in a shattering cascade. Phylogenetic reconstruction, syntenic relationships, genomics loci, promoter sequences, and identification of transcription factor-binding sites (TFBSs) faced shattering cascade genes’ analysis. Among these, three genes, SHATTERPROOF1, SHATTERPROOF2, and FRUITFUL (SHP1, SHP2, FUL), belonged to a MADS-box family implicated in fruit dehiscence zone and valve margin constitute a core regulatory module. But, in Brassica, the exact number of genes involved in shattering remained obscure. Grouping BnSHP1-N, BnSHP2-N, and BnFUL-N into their respective clades was according to phylogenetic reconstruction of core regulatory modules (SHP1, SHP2, and FUL) and from other species homologs. The eight shattering cascade genes showed no conservation, indicating their involvement in crushing through separate pathways. The increased number of homologs/paralogs in Brassica was due to occurrences of genome duplication or a triplication event during evolution. Exonization and intronization could be responsible for a variable number and size of the exons and introns in gene structures. Comparative genome synteny analysis of SHP1, SHP2, and FUL revealed correlation and evolutionary insights into gene region relationships in all Brassicaceae. Study results provided basic information on cloning, phylogenetic reconstruction, genomics loci, and identifying transcription factor-binding sites (TFBSs) of core regulatory module genes that might be helpful for developing shattering-resistant genome-edited plants to prevent future yield losses in canola.

Microscopical Analysis of Autofluorescence as a Complementary and Useful Method to Assess Differences in Anatomy and Structural Distribution Underlying Evolutive Variation in Loss of Seed Dispersal in Common Bean.

The common bean has received attention as a model plant for legume studies, but little information is available about the morphology of its pods and the relation of this morphology to the loss of seed dispersal and/or the pod string, which are key agronomic traits of legume domestication. Dehiscence is related to the pod morphology and anatomy of pod tissues because of the weakening of the dorsal and ventral dehiscence zones and the tensions of the pod walls. These tensions are produced by the differential mechanical properties of lignified and non-lignified tissues and changes in turgor associated with fruit maturation. In this research, we histologically studied the dehiscence zone of the ventral and dorsal sutures of the pod in two contrasting genotypes for the dehiscence and string, by comparing different histochemical methods with autofluorescence. We found that the secondary cell wall modifications of the ventral suture of the pod were clearly different between the dehiscence-susceptible and stringy PHA1037 and the dehiscence-resistant and stringless PHA0595 genotypes. The susceptible genotype had cells of bundle caps arranged in a more easily breakable bowtie knot shape. The resistant genotype had a larger vascular bundle area and larger fibre cap cells (FCCs), and due to their thickness, the external valve margin cells were significantly stronger than those from PHA1037. Our findings suggest that the FCC area, and the cell arrangement in the bundle cap, might be partial structures involved in the pod dehiscence of the common bean. The autofluorescence pattern at the ventral suture allowed us to quickly identify the dehiscent phenotype and gain a better understanding of cell wall tissue modifications that took place along the bean's evolution, which had an impact on crop improvement. We report a simple autofluorescence protocol to reliably identify secondary cell wall organization and its relationship to the dehiscence and string in the common bean.

Ultrastructure of four Surirella taxa (Bacillariophyceae) from Qinghai Province, northwest China, with reference to the characteristics of portulae

During our investigations on the freshwater diatoms from Qinghai Province, China, four sympatric Surirella taxa belonging to the group Pinnatae were analysed. Based on morphological observations derived from light and scanning electron microscopy, three of these four taxa were identified as: S. minuta, S. lacrimula, and S. brebissonii var. kuetzingii. The fourth taxon is described as Surirella liubingii sp. nov., a new species with a unique combination of characteristics. These include the distribution pattern of its costa-stria bundles (CSBs) alternating with its over-fibula costae (OFCs), which is formed by the distinctly elevated CSBs on the valve face, mostly composed of three costae, and OFCs with a remarkedly lower position. Other characteristics include the presence of robust fibulae extending to the valve midline, the presence of only one portula between two adjacent fibulae, and a “pseudoseptum” extending internally from the valve margin. From the observations on these four Surirella taxa, we described and discussed two types of fibula (one in which the fibula nearly reaches the valve midline and one with short fibula) and two types of portula morphology (one with only one portula between two adjacent fibulae and the other with 2–4 portulae between two adjacent fibulae).

Chamaepinnularia taihangensis sp. nov. (Bacillariophyceae), a new diatom species from Taihang Valley, Shanxi province, China

A new species was discovered in Taihang Valley, Shanxi province, China. It shared the typical characteristics of the genus Chamaepinnularia, such as chambered striae, vela-covered areolae and small frustules. Valves of Chamaepinnularia taihangensis sp. nov. are linear-lanceolate with capitate apices. Valve margins showed distinct triple curvatures in light microscopy. Axial area and central area narrow, rhombic. The new species was compared with the four related taxa, C. hassiaca, C. justa, C. krookiformis and C. soehrensis. These species differed from the new species in valve outline, valve size, stria density and the shape of the central area. The details of the valves as shown by light and scanning electron microscopy are described. This new species occurs in benthic and epiphyte habitats. We discuss the ecological breadth and systematic position of the genus Chamaepinnularia.

The diatom genus Humidophila (Bacillariophyta) in an historic Delogne sample with the description of 2 new species

ABSTRACT During the analysis of a voucher sample from Frahan (Belgium) collected by the Belgian diatomist Charles-Henri Delogne, seven species from the genus Humidophila (Bacillariophyta) have been observed. Two species could not be identified using the currently available literature and are described as new to science. Humidophila delognei sp. nov. has always been identified in the past as H. contenta, but based on recent analysis of the original type material of the latter, it was clear that the currently accepted concept of the species was wrong. The new species is characterised by parallel valve margins, a linear valve outline, a distinct central fascia and T- or Y-shaped raphe endings. The other new species, H. aspera sp. nov., has undulating valve margins and distinct, though irregular siliceous markings in the central and axial area. The sample from Frahan was also indicated in 1885 by Henri Van Heurck as being the original material for the newly described species Humidophila (Navicula) flotowii, long considered a synonym of H. perpusilla. Both species can, however, be separated based on a different length/width ratio, with H. flotowii showing more slender, elongated valves. Other Humidophila species in the sample include H. contenta, H. laevissima, H. perpusilla and H. simplex. Navicula fragilarioides, a new name once introduced for Fragilaria laevissima, the basionym of H. laevissima, is lectotypified based on an original Krasske slide.

Integrative Taxonomy of Cyclocyprididae Kaufmann, 1900 (Ostracoda: Podocopa) with Description of a New Genus and Species.

The two widespread ostracod genera Cypria Zenker, 1854 and Physocypria Vávra, 1897 are traditionally distinguished based on the presence or absence of tubercles on the right valve margin. However, recent research based on soft body parts has uncovered new cryptic genera within Cypria and Physocypria. Following this line of research, a new Cyclocyprididae genus and species, Vizcainocypria viator gen. nov. sp. nov., is here described from individuals collected in rice fields and wetlands of the Iberian Peninsula. Vizcainocypria is compared with Cypria, Physocypria, Dentocypria Savatenalinton, 2017, Keysercypria Karanovic, 2011, Brasilocypria Almeida et al., 2023, and Claudecypria Almeida et al., 2023 based on morphological evidence. Besides the presence or absence of tubercles on the right valve, these genera can be distinguished according to their mandibular palp, second thoracopod, caudal ramus, and male hemipenis. Molecular analyses using mitochondrial (COX1), and nuclear (28S rDNA) genes provide further support for the differentiation of Cypria, Dentocypria, Physocypria and Vizcainocypria gen. nov. The present study highlights the importance of using an integrative taxonomy approach, combining shell and soft-body parts morphology and molecular data, to characterize the rich diversity of freshwater ostracods.

Новый вид остракод рода Leperditia из силурийских отложений западного склона Приполярного Урала

The article describes a new species of ostracods of the genus Leperditia from the Upper Silurian deposits of the western slope of the Subpolar Urals (Shchugor River basin). Leperditia unituber Saldin sp. nov. differs from all other species of Leperditia by the presence of a tubercle near the ventral margin of the right valve, a stable diagnostic character.
 The shell is truncated-oval, elongated, widening towards the posterior end. The ventral margin is gently and asymmetrically arched. Longitudinal axis at a slight angle to the length. A narrow marginal border is observed along the ends of the shell. The posterior dorsal swelling on the left valve is pronounced. On the right valve near the ventral part, where the greatest height of the shell is observed, there is a tubercle or spiny outgrowth.

First recent finding of scallop <i>Chlamys lioica</i> (Pectinidae, Bivalvia)

The purpose of this study was to inform on a first recent finding of scallop Chlamys (?) lioica (Dall, 1907).The research methods consist in description of specimens found in according with generally accepted methods.Results: Two alive specimens of scallop, unlike any known recent Pectinidae from the Northwest Pacific were found in the area of scallop fishery at north Kurile Islands in 2012 and 2017. These specimens identified as Pecten (Chlamys) lioicus Dall, 1907, known before as fossil only.Discussion: The main taxonomic features confirm belonging of these specimens to the genus Chlamys. Some another features as well developed commarginal lamellae of external valves surface, absence of reticulated microsculpture and smooth ventral margin of valves differ these specimens from another Chlamys s. str. species. The correct systematic position of this species may be clarified after examination of additional materials, the name Chlamys lioica (Dall, 1907) may be used until that.The novelty of research is in first recent finding of Chlamys lioica.Conclusion. Two findings of this species at North Kuriles were recorded only. However, this species may inhabit areas outside of main scallop fishing grounds. Rare findings may be explained by rare occasional relocation of some specimens from typical native grounds.

Xenobennettella coralliensis a new monoraphid diatom genus characterized by the alveolate sternum valve with cavum, observed from coral reef habitats.

During a survey of benthic diatoms from the coral reefs of the Indian Ocean (Scattered Islands) and Pacific Ocean (Tuamotu Archipelago), an interesting monoraphid diatom was observed and examined by light microscopy and various electron microscopy methods including Focus Ion Beam milling. Our thorough analysis revealed the similarity of this diatom to Bennettella R.W.Holmes, which we reference in the name: Xenobennettella Witkowski & Riaux-Gobin gen. nov., with Xenobennettella coralliensis Witkowski & Riaux-Gobin sp. nov. as the generitype. The type habitat for this new species is the sublittoral coral reef of Juan de Nova in the Mozambique Channel. The sternum valve of the new genus is characterized by an alveolate ultrastructure with the rim of the alveola opening along the valve margin, resembling the sternum valve of Bennettella. Internally, Xenobennettella differs from the latter by possessing a cavum (horseshoe-shaped chamber) on one side of the valve, in a central axial position. The raphe valve of Xenobennettella has small, marginal, apically elongate chambers, which are internally delineated by transapical ribs that are very similar to Bennettella. However, the raphe in the new genus is different from the latter, resembling some Cocconeis and Planothidium with internal raphe endings bent in the opposite direction, while resembling some Planothidium taxa externally by ending on the apical part of the mantle. This contrasts to Bennettella, which has a unique raphe system, with external raphe endings below the apices, a prominent axial structure and a transapically expanded central area. Likewise, the external surface of Bennettella is different from that of the new genus with a complex mantle structure and biseriate striae. In Xenobennettella, the valve mantle of the raphe valve is simple and perforated by areola. The transapical striae occur in the valve margin and the axial area is ornamented along its course with a single row of densely packed areola on both sides. The characteristics of the raphe valve and alveolate sternum valve place the new genus among the Achnanthidiaceae.

A new marine epipsammic diatom species, Ambodajingensis sp. nov. (Bacillariophyceae), from the coast of Southeast China.

Ambodajingensis HH Liu, Z Wang, YH Gao & CP Chen, sp. nov. is described as a new species in samples collected from sand grains at Dajing Beach, Ningde City, Fujian Province, China. Morphological details of the new species with respect to valve shape, size and valve ultrastructure are presented based on light microscopy (LM) and scanning electron microscopy (SEM). The main features of Ambodajingensis under a light microscope are elongated elliptic valves with rounded apices, two internal costae on the valve and rectangular in girdle views. SEM observation showed that externally, the frustules are comprised of two valves with a relatively deep mantle and a transition between the valve faces. Small, flabelliform spines are present along the valve margin. Internally, the valves are divided into three sectors by robust costae, which penetrate the whole valve lumen and are thickest at the mantle interior and thinner toward the center. The sternum is narrow and linear, visible only in the valve apex, set off by costae. The striae are comprised of small, round areolae and they are parallel in the middle to slightly radiate at the apices. The new species is compared with other species in the genus Ambo.

Distribution of Diaphanosoma (Diplostraca: Sididae) genus in Central Europe – morphological and molecular approach

Diaphanosoma brachyurum is a dominant component of summer zooplankton in Central Europe. So far only this species has been known from Poland, and other species from this genus have been found in neighboring countries. The aim of the present study was to present the factual distribution of Diaphanosoma species in Central Europe. We investigated Diaphanosoma individuals in 109 water bodies in Central Europe (mostly from Poland) by combining morphological analyses and molecular methods (mtDNA COI gene). Our research confirmed the presence of three other species - D. orghidani, D. mongolianum, and D. cf. lacustris. We provided a detailed morphological description for every species and pointed out that each species can be easily distinguished morphologically by armament of postero-ventral valve margins. The results of phylogenetic analysis based on 27 haplotypes of mtDNA COI gene lead to the same conclusion as morphology. Our genetic and morphological analysis confirms a close affinity between D. mongolianum and D. lacustris, as well as the presence of hybrids between these species. Nevertheless, the most common was D. brachyurum - it was found in 97 water bodies, and other Diaphanosoma species begin to penetrate Central Europe via rivers.

Four new species of the genus Lacustriella (Bacillariophyta) from Lake Baikal

We add four new species to the recently established genus Lacustriella Kulikovskiy, Lange-Bertalot et Metzeltin and characterize morphology of the taxa based on LM and SEM observations. Lacustriella cuspidata, L. rombea, L. radiata and L. solita share all of the typical morphological features of the genus including longitudinal canal along each valve margin, radiate uniseriate striae terminated with large elongated areolae, and external distant raphe ends bent oppositely. L. cuspidata is peculiar among the other Lacustriella with rows of small pores look as if they continue striae on the surface of longitudinal canals as well as with the axial area sharply widened into the asymmetrical central area. L. rombea is different in combination of valve outline with unprotracted rostrate apices, irregular areolation at centre of the external valve, and slit-like areola occluded with volae. In L. radiata distinctive characters include protracted rostrate valve apices, rhombic central area and volated slit-like areolae. L. solita differs in the highest density of areolae in striae and an ornamented surface of longitudinal canals. New species were compared to the closest morphologically similar taxa. Some general ecological properties and distribution in the littoral zone of the ancient lake are given.