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62. Planorbis carinatus O. F. Müller, 1774 Findings in Serbia. Planorbis carinatus: Hesse (1929); Jaeckel et al. (1958); Karaman (2005); Karaman & Karaman (2007). Common name. Keeled ramshorn. Morphology. Medium-sized snail (up to 15 mm diameter). Shell is flattened and keeled, keel is sharp, centrally positioned. Whorls are rapidly increasing. For more details see Welter-Schultes (2012: 68, figure in the middle of the page). Distribution and ecology. Western Palearctic species up to 1000 m.a.s.l. Permanent standing and slow-flowing waters with a muddy substrate and plenty of vegetation (Welter-Schultes 2012). In Serbia, it could be found in the northern, Pannonian, parts, usually in ponds, permanent marshes and accumulations near the Danube and Sava Rivers (Zasavica, Petrovaradinski rit, Srebrno jezero). There are also findings from the southern parts (Toplica River). Other remarks. On the IUCN Red List it has been assessed as LC (Van Damme & Kebapçý 2011 b)., Published as part of Marković, Vanja, Gojšina, Vukašin, Novaković, Boris, Božanić, Milenka, Stojanović, Katarina, Karan-Žnidaršič, Tamara & Živić, Ivana, 2021, The freshwater molluscs of Serbia: Annotated checklist with remarks on distribution and protection status, pp. 1-64 in Zootaxa 5003 (1) on pages 31-32, DOI: 10.11646/zootaxa.5003.1.1, http://zenodo.org/record/5120059, {"references":["Hesse, P. (1929) Schnecken aus dem nordlichen Serbien. Archiv fur Molluskenkunde, 61 (1), 230 - 240.","Jaeckel, S. V., Klemm, W. & Meise, W. (1958) Die Land und Susswasser-Mollusken der nordlichen Balkanhalbinsel. Abhandlungen und Berichte aus dem staatlichen Museum fur Tierkunde Dresden, 23, 141 - 205.","Karaman, B. (2005) Fauna Gastropoda (Mollusca) sliva Juzne Morave (Srbija i Crna Gora). Crnogorska Akademija nauka i umjetnosti, Glasnik odeljenja prirodnih nauka, 16, 41 - 49. [in Serbian]","Karaman, B. & Karaman, G. (2007) Catalogus of the freshwater snails (Mollusca, Gastropoda) of Serbia. Crnogorska Akademija Nauka i Umjetnosti Glasnik Odjeljenja prirodnih nauka, Podgorica, 17, 167 - 222.","Welter-Schultes, F. W. (2012) European non-marine molluscs, a guide for species identification, planet poster editions. Planet Poster Editions, Gottingen, 674 pp. [in German]","Van Damme, D. & Kebapcy, U. (2011 b) Planorbis carinatus. The IUCN Red List of Threatened Species, 2011, e. T 156070 A 4883728. [downloaded 3 May 2021]"]}

Data on historical change of the Transbaikalian malacofauna in the Neopleistocene and Holocene is presented. Fossil shells from archeological excavations of the ancient settlements dating from the Neolithic period to Medieval and also from a drill hole of the Neopleistocene alluvial deposits were collected. In total nine species of bivalve molluscs from the families Margaritiferidae, Unionidae, Limnocardiidae, Glycymerididae, including one marine species, and two gastropod species from families Viviparidae and Planorbidae were identified. The time of the existence of each fossil species was determined by radiocarbon dating. It was found that the species ranged in age from more 50,000 and 2,080–1,210 years ago. Five species inhabited the Transbaikal region and are locally extirpated in the present. Their disjunctive ranges in the past included southern Europe and Western and Eastern Siberia to Transbaikalia and in the east to Far East and Primorye of Russia. The time of existence and extirpation of the thermophilic species of genera Adacna, Planorbis, Lanceolaria and Amuropaludina corresponds to cycles of the warming and cooling in Pleistocene and Holocene according to regional climate chronological scales. It was possible to separate these species as indicators of paleoclimate. Change of the species composition of the malacofauna of region connected with natural cycles of climatochrons in the Pleistocene and Holocene is the appearance of the climatogenic succession. In the course of this succession the disappearance of the stenothermal species occurred on a regional level and decreasing their global ranges.

The following three new species of Trypetheliaceae are described from Sri Lanka: Astrothelium inspersoconicum, A. isohypocrellinum, and Polymeridium fernandoi. Ten species are newly recorded from Sri Lanka: Astrothelium flavoduplex, A. galligenum, A. scoria, A. straminicolor, Constrictolumina planorbis, C. porospora, Dictyomeridium proponens, Marcelaria cumingii, Polymeridium jordanii, and Pseudopyrenula media.

Planorbis planorbis (Linnaeus, 1758) (fig. 3, 9–11) Distribution. According to our data, the species is one of the rarely recorded pulmonate snails in the region — we found its populations in only two localities: 13 and 15 (table 1). In Ukraine P. planorbis is registered in all regions (Anistratenko, Сhernogorenko, 1989; Stadnichenko, 1990) including the Transcarpathia (Zdun, 1960; Stadnichenko, Gyrin, 2011 b; Anistratenko et al., 2018). Global distribution — Europe, Northern Africa, and Siberia (Vinarski, Kantor, 2016). Remarks. In the studied region P. planorbis inhabits stagnant (even temporary or semi-permanent) and running waters usually occurring in- and under stones or macrophytes. We recorded P. planorbis only in lowland part of the region at a depth of 0.3–0.5 m (table 1, 2)., Published as part of Anistratenko, V. V., Furyk, Yu. I., Anistratenko, O. Yu. & Degtyarenko, E. V., 2019, A Review Of Species Diversity, Distribution And Ecology Of Freshwater Gastropod Molluscs Inhabiting The Ukrainian Transcarpathian, pp. 349-374 in Vestnik Zoologii 53 (5) on page 368, DOI: 10.2478/vzoo-2019-0033, http://zenodo.org/record/6949164, {"references":["Stadnichenko A. P. 1990. Fauna Ukraine: In 40 vol. Vol. 29: Mollusca. Fasc. 4: Lymnaeiformes (physids, bulinids, planorbids). Naukova dumka, Kiev, 1 - 282 [In Russian].","Zdun, V. I. 1960. On the fauna of Transcarpathian Mollusca, Naukovi Zapyski Lvivskogo naukovo-pryrodnychogo museyu AN URSR, 8, 83 - 95 [In Ukrainian].","Stadnichenko, A. P., Gyrin, V. K. 2011 b. On fauna and ecology of fresh-water molluscs of the Transcarpathian (families Planorbidae, Valvatidae, Viviparidae, Hydrobiidae, Bithyniidae, Lithoglyphidae, Unionidae, Pisidiidae). Communication 2. Wyksztalcenie i nauka bez granic- 2011. Materialy VII Miedzynarodowej naukowi-praktycznej konferencji 07 - 15 grudnia 2011 roku, Vol. 25. Biologiczne nauki. Nauka i studia, Przemysl, 22 - 24 [In Russian].","Anistratenko, V. V., Vinarski, M. V., Anistratenko, O. Yu., Furyk, Yu. I., Degtyarenko, E. V. 2018. New data on pond snails (Mollusca: Gastropoda: Lymnaeidae) inhabiting the Ukrainian Transcarpathian: diversity, distribution and ecology. Ecologica Montenegrina, 18, 1 - 14.","Vinarski, M. V., Kantor, Yu. I. 2016. Analytical catalogue of fresh and brackish water molluscs of Russia and adjacent countries. A. N. Severtsov Institute of Ecology and Evolution of RAS, Moscow, 1 - 544."]}

Genus Planorbis O. F. Müller, 1774 Type species: Helix planorbis Linnaeus, 1758, Published as part of Anistratenko, V. V., Furyk, Yu. I., Anistratenko, O. Yu. & Degtyarenko, E. V., 2019, A Review Of Species Diversity, Distribution And Ecology Of Freshwater Gastropod Molluscs Inhabiting The Ukrainian Transcarpathian, pp. 349-374 in Vestnik Zoologii 53 (5) on page 368, DOI: 10.2478/vzoo-2019-0033, http://zenodo.org/record/6949164

Identification of cercariae was long based on morphological and morphometric features, but these approaches remain difficult to implement and require skills that have now become rare. Molecular tools have become the reference even though they remain relatively time-consuming and expensive. We propose a new approach for the identification of cercariae using MALDI-TOF mass spectrometry. Snails of different genera (Radix, Lymnaea, Stagnicola, Planorbis, and Anisus) were collected in the field to perform emitting tests in the laboratory. The cercariae they emitted (Trichobilharzia anseri, Diplostomum pseudospathaceum, Alaria alata, Echinostoma revolutum, Petasiger phalacrocoracis, Tylodelphys sp., Australapatemon sp., Cotylurus sp., Posthodiplostomum sp., Parastrigea sp., Echinoparyphium sp. and Plagiorchis sp.) were characterized by sequencing the D2, ITS2 and ITS1 domains of rDNA, and by amplification using specific Alaria alata primers. A sample of each specimen, either fresh or stored in ethanol, was subjected to a simple preparation protocol for MALDI-TOF analysis. The main spectral profiles were analyzed by Hierarchical Clustering Analysis. Likewise, the haplotypes were analyzed using the maximum likelihood method. Analytical performance and the log-score value (LSV) cut-off for species identification were then assessed by blind testing. The clusters obtained by both techniques were congruent, allowing identification at a species level. MALDI-TOF enables identification at an LSV cut-off of 1.7 without false-positives; however, it requires more data on closely related species. The development of a “high throughput” identification system for all types of cercariae would be of considerable interest in epidemiological surveys of trematode infections.

The article presents the data on distribution and defeat of gastropod mollusks by parasitic trematodes in biotopes of small reservoirs (rivers, lakes and swamps) of the Dnipro basin of northern regions of Ukraine. During the 2016–2017 years, at the following areas were collected and identified: Lymnaea (L.) stagnalis (Linnaeus, 1758); L. truncatula (Müller, 1774); Planorbis (P.) corneus (Linnaeus, 1758); P. рlanorbis (Linnaeus, 1758); Viviparus contectus (Millet, 1813); Valvata piscinalis (Müller, 1774) and Succinea pfeifferi (Rossmässler, 1834). The microscopic study of the mollusks’ liver allowed us to detect the presence of pathogens of cattle trematodoses inside a certain number of the snails – Fasciola hepatica (Linnaeus, 1758) and Paramphistomum sp. (Fischoeder, 1901). At biotopes of small rivers, 8.3% of mollusks L. truncatula species, 23.5% of L. stagnalis and 5.7% of P. corneus were affected. At lakes and swamps, the number of affected L. truncatula was 36.3%, and L. stagnalis – 13.7%. It was determined the defeat of ruminants with fasciolosis and paramfistomatoses in designated regions. It testifies to the formation of sustainable natural foci of these invasions., У статті представлені дані про поширення та ураження черевоногих молюсків паразитичними трематодами в біотопах малих водойм (річок, озер і боліт) басейну Дніпра північних регіонів України. Упродовж 2016–2017 років у дослідних областях були зібрані та ідентифіковані: Lymnaea (L.) stagnalis (Linnaeus, 1758); L. truncatula (Müller, 1774); Planorbis (P.) corneus (Linnaeus, 1758); P. rlanorbis (Linnaeus, 1758); Viviparus contectus (Millet, 1813); Valvata piscinalis (Müller, 1774) і Succinea pfeifferi (Rossmässler, 1834). Мікроскопічне дослідження печінки молюсків дозволило виявити наявність збудників трематодозів великої рогатої худоби всередині певної кількості равликів – Fasciola hepatica (Linnaeus, 1758) і Paramphistomum sp. (Fischoeder, 1901). У біотопах малих річок уражені 8,3% молюсків L. truncatula, 23,5% L. stagnalis та 5,7% P. corneus. На озерах і болотах кількість уражених L. truncatula становила 36,3%, а L. stagnalis – 13,7%. Визначено ураження жуйних тварин фасціолозом і парамфістоматозами у визначених регіонах. Це свідчить про формування стійких природних вогнищ цих інвазій., В статье представлены данные о распространении и поражении брюхоногих моллюсков паразитическими трематодами в биотопах малых водоемов (рек, озер и болот) бассейна Днепра северных регионов Украины. В течение 2016–2017 годов в исследуемых областях были собраны и идентифицированы: Lymnaea (L.) stagnalis (Linnaeus, 1758); L. truncatula (Müller, 1774) Planorbis (P.) corneus (Linnaeus, 1758); P. rlanorbis (Linnaeus, 1758); Viviparus contectus (Millet, 1813); Valvata piscinalis (Müller, 1774) и Succinea pfeifferi (Rossmässler, 1834). Микроскопическое исследование печени моллюсков позволило выявить наличие возбудителей трематодозов крупного рогатого скота внутри определенного количества улиток – Fasciola hepatica (Linnaeus, 1758) и Paramphistomum sp. (Fischoeder, 1901). В биотопах малых рек заражены 8,3% моллюсков L. truncatula, 23,5% L. stagnalis и 5,7% P. corneus. На озерах и болотах количество зараженных L. truncatula составляла 36,3%, а L. stagnalis – 13,7%. Определены поражения жвачных животных фасциолозом и парамфистоматозами в определенных регионах. Это свидетельствует о формировании устойчивых природных очагов этих инвазий.

A new Planorbis sp., P. cretensis n. sp., is described from a material collected in Crete. The new species is compared with two other small species of the genus occuring in the Mediterranean region, Planorbis agraulus from Algeria and P. moquini from Corsica.

Terminal portions of the male copulatory apparatus of Planorbis planorbis, Segmentina oelandica, and Anisus vortex were studied using whole-mount preparations, serial semi-thin sections, and transmission electron microscopy. In the latter species, stylet formation was investigated at several stages of postembryonic development. Organization of the penial distal portion in the species studied varies greatly. In P. planorbis, the distal end of the penis lacks developed papillae and is armed with a stylet built up of the covering epithelial cells of the penis proper. In A. vortex, the stylet is formed by the secretory activity of the middle cells of the distal portion of the penis. To the time of maturation, the cells encompassing the stylet are broken down exposing its solid chitinous structure and characteristic shape. In S. oelandica, the distal end of the penis bears the long probably flexible papilla with the characteristics of an internal ‘skeleton,’ organized as a line of connective tissue cells and a...

dentifer, Planorbis, J. Moricand, 1853: 37. Type locality: [Brazil] le lac Baril, près Bahia [Blanchet]. Syntypes: MHNG-INVE-86932 (3) (Planorbidae) [Figs 34-36]., Published as part of Breure, Abraham S. H. & Tardy, Emmanuel, 2016, From the shadows of the past: Moricand senior and junior, two 19 th century naturalists from Geneva, with their newly described taxa and molluscan types, pp. 113-138 in Revue suisse de Zoologie 123 (1) on page 121, DOI: 10.5281/zenodo.46292

A high-resolution outcrop to subsurface gamma-ray correlation of the Lower Lias across S\V Britain is presented. The study focuses upon the mud-dominated, fully marine Rhaetian to Pliensbachian succession that outcrops in the Bristol Channel and Wessex Basins. The succession has been divided into eighteen correlatable spectral gammaray units. Boundaries of the gamma-ray units do not cross time-lines inferred from the biostratigraphy. Correlation of the spectral gamma-ray units N-S across the Bristol Channel suggests a hiatus at the boundary of the planorbis and liasicus ammonite zones in Somerset relative to the coeval section in Glamorgan. The outcrop-based gamma-ray units have also been identified in the subsurface from total gamma-ray logs in both the Burton Row borehole, Somerset, and in the Winterborne Kingston borehole, Dorset. Correlation is therefore possible across numerous fault blocks and between different basins. © 1997 Geologists' Association.

During the survey of freshwater snail hosts and their digenean larval trematode parasites, a rare cercaria larva belonging to family Transversotrematidae and subclass Digenea (Trematoda) was recovered from the snail species Melanoides striatella tuberculata inhabiting perennial Som river of Udaipur district, Rajasthan, India. More than 28 % mature specimens of these snails were found to be infected with transversotrematid cercaria larvae in the spring season. Body of this cercaria is large, bowl-shaped, biocellate, spinose, transparent and laterally extended having two pigmented eye spots, two hold fast organs extended from the junction of body and tail, large tail with two foliated furcal rami, and cyclocoel intestinal caeca. As far as the authors are aware, this is the first record of a transversotrematid larva from Rajasthan, India. Simultaneously, other forms of cercariae viz., amphistome, echinostome, monostome, gymnocephalous, furcocercous and xiphidiocercous cercariae were also recovered from fifteen species of pulmonate and operculate snails including Lymnaea acuminata f. patula, L. acuminata f. chlamys, L. acuminata f. typica, L. acuminata f. rufescens, L. luteola f. australis, L. luteola f. typica, L. luteola f. impura, Planorbis (Indoplanorbis) exustus, and Anisus (Gyraulus) convexiusculus, Faunus ater, Melania (Plotia) scabra, Thiara (Tarebia) lineata, Melanoides striatella tuberculata, Vivipara bengalensis race gigantica and V. bengalensis race mandiensis. The seasonal occurrence and host-specificity of diverse trematode cercaria larvae are also discussed besides the first record of a rare transversotrematid cercaria larva from Rajasthan, India.

Franz Martin Hilgendorf (1839–1904), assistant and later curator at the Natural History Museum in Berlin, is mainly known for his palaeontological studies about Miocene planorbids of the Steinheim Basin, Southern Germany, a topic on which he already wrote his dissertation in 1863. After having been introduced to the geology and in particular stratigraphy of Steinheim in summer 1862 by his teacher Friedrich August Quenstedt, who later did not follow his interpretations, though, Hilgendorf traveled to Steinheim repeatedly. Based on these studies he published between 1866 to 1901 several papers on transformation series, or Formenreihen, of the freshwater gastropod “Planorbis multiformis ” (today assigned with several species to the genus Gyraulus), which reflect a scientific controversy that lasted for another century. Following earlier hints as to its existence, we re-discovered Hilgendorf’s original, handwritten dissertation of 42 pages in the archives of the Berlin Natural History Museum (Historische Arbeitsstelle), together with a rich literary bequest that has not been studied yet. Discussing some of its implications, we here present for the first time a complete transcription of Hilgendorf’s German text that had never been published before, showing that he at that very early stage explicitly contextualized his Steinheim findings with Darwin’s new theory of evolution, i.e. phylogenetical relationships of descendants through time. In addition, we report on and depict Hilgendorf’s curious arrangements on five cardboards, comprising the shells of planorbids as transformation series with transition of taxa, plus one card revealing his first phylogenetic tree that is found among his collection of material from Steinheim in the Palaeontological Collection of the Berlin Natural History Museum. With these Steinheim snails Hilgendorf not only described one of the first evolutionary transformations illustrating both ana- and cladogenesis, but created the first phylogenetic reconstruction on the basis of existing fossil evidence.

This paper presents the first quantitative study of the Early Jurassic recovery of ammonoids after the end-Triassic mass extinction based on detailed U–Pb ID-TIMS (isotope dilution thermal ionization mass spectrometry) geochronology from ash bed zircons placed within a clear phylogenetical and biochronological framework at the subzonal and species level. This study was triggered by the discovery of a rich Peruvian succession of ammonites, deposited concomitantly with an unusually large number of ash beds. Two major phases of rediversification are observed during the Psiloceras spelae and Angulaticeras zones that correspond to positive peaks in the δ13Corg curve, providing a possible link between biodiversity and the global carbon cycle. In the case of the post-extinction recovery, the development of the earliest Hettangian ammonites occurs within the genus Psiloceras, which begins with the occurrence of P. spelae and then explodes into worldwide development of smooth psiloceratids of the Psiloceras planorbis group s.l. This rapid biodiversification likely occurred less than 100 ka after the end-Triassic crisis; the genus Psiloceras occupied all the possible ecological niches worldwide, from the Pacific deep waters to the NW European shallow deposits and also in some rare Tethyan occurrences like at Germig in Tibet. This global dispersion allowed the differentiation of the group in several major phyla, the Schlotheimiidae, Discamphiceratinae, Arietitidae and Lytocerataceae, which were the roots of all other Jurassic and Cretaceous ammonites.

Although Planorbidae are one the most common and diverse families of pulmonates, their mating behaviour is known only for a few species. This paper describes mating behaviour and copulatory mechanics in four species of the Planorbidae: Anisus vortex (Linnaeus, 1758), Bathyomphalus sontortus (Linnaeus, 1758), Choanomphalus riparius (Westerlund, 1865) and Planorbis planorbis (Linnaeus, 1758), and supplements previously published observations on two other species: Segmentina oelandica (Westerlund, 1885) and Planorbella (Seminolina) duryi (Wetherby, 1879). Patterns of musculature of the penial complex [in all species except P. (S.) duryi] were studied using fluorescent phalloidin dye specific for actin filaments. Choanomphalus riparius, P. planorbis and S. oelandica were shown to mate by shell mounting and display an elaborate courtship behaviour accompanied by shell-circling. Planorbella (S.) duryi mates in a face-to-face position; in this species, courtship is accompanied by mechanical stimulation of the partner’s plicae. Anisus vortex and B. contortus do not exhibit any distinct precopulatory behaviour and mate face-to-face. It is argued that Planorbidae show a relationship between gender expression (functional protandry vs simultaneous hermaphroditism) and mating behaviour (unilateral vs reciprocal mating). The taxonomic utility of the copulatory behaviour and penial musculature is discussed.

The mollusc fauna of the early Middle Miocene (Langhian) intramontane Alpine Lake Groisenbach is described for the first time. The shells derive from the Feistring Formation in the Aflenz Basin in Austria, which was covered by Lake Groisenbach. The assemblage is moderately diverse with 12 gastropod and 2 bivalve species, suggesting shallow lacustrine and fluvial settings. Among the gastropods, only Theodoxus crenulatus (Klein, 1853) is known from other Miocene localities, whilst all other species are documented so far only from Lake Groisenbach. None of the Early and Middle Miocene lake systems of the Alpine-Carpathian Foredeep and the Balkan Peninsula displays any faunistic resemblance with this new fauna. Even coeval lake faunas from the close-by Graz Basin have no species in common with Lake Groisenbach. This pattern points to a surprising endemicity and biogeographic fragmentation in the Central European freshwater systems during the Early and Middle Miocene. The uniqueness of the newly described fauna is also indicated by the completely erratic occurrence of the otherwise African-Mediterranean genus Bulinus, which is unknown from all other central European Miocene freshwater systems. Emmericia roetzeli Harzhauser and Neubauer nov. sp., Nematurella zuschini Neubauer and Harzhauser nov. sp., Romania fastigata Neubauer and Harzhauser nov. sp., Odontohydrobia groisenbachensis Neubauer and Harzhauser nov. sp., Odontohydrobia pompatica Neubauer and Harzhauser nov. sp., Odontohydrobia styriaca Harzhauser and Neubauer nov. sp., Planorbis austroalpinus Harzhauser and Neubauer nov. sp., Gyraulus sachsenhoferi Harzhauser and Neubauer nov. sp., Bulinus corici Harzhauser and Neubauer nov. sp., Ferrissia crenellata Harzhauser and Neubauer nov. sp. and Stagnicola reinholdkunzi Harzhauser and Neubauer nov. sp. are introduced as new species.

Though triclad planarias could limit littoral snail recruitment by preying on eggs with their muscular ventral pharynx, planarian predation on eggs has never been quantified. Intact egg clutches encompassing eight snail species x three developmental stages were offered to Dugesia (= Schmidtea) polychroa (Paludicola: Dugesiidae) individuals (body length = 6-12 mm) in one-on-one, no-choice 24-h feeding trials to gain a first insight on snail egg palatability to dugesiid planarias. Predatory losses were quantified as differences in planaria-present trials v.s. parallel planaria-absent controls. D. polychroa predation on snail eggs was generally low. Eggs in monolayered, flat clutches of bithyniids (Bithynia leachii) and planorbids (Planorhis planorbis, Helisoma trivolvis, and Planorbarius corneus) were more susceptible to planarian predation than multilayered eggs in sausage-shaped clutches of physids (Physa acuta) and lymnaeids (Lymnaea stagnalis, Radix auricularia, and Stagnicola fuscus). Planarian predation also was higher on smaller eggs, and was not related to planarian body size. Vulnerability was also markedly species-specific, with appreciable losses recorded only for pre-hatching eggs of P. planorbis and, to a lesser extent, H. trivolvis. The results suggest that, with the possible exception for the soft-clutch, small eggs of P. planorbis, predation by D. polychroa on eggs does not impact gastropod recruitment appreciably.

Rhodamine B and Rhodamine WT are fluorescent dyes commonly used as tracers in hydrological investigations. Since introducing intensely red substances into rivers raises understandable doubts of ecological nature, the authors aimed at examining the influence of these dyes on small water fauna using bioindication methods. Quantitative results, calculated with the use of Bliss-Weber probit statistical method, were achieved by means of standardized ecotoxicological tests containing ready-to-hatch resting forms of fairy shrimp (Thamnocephalus platyurus). Qualitative studies included observation of water flea crustacean (Daphnia magna) and horned planorbis snail (Planorbis corneus), both typically present in rivers and representative for temperate climate, as well as guppy fish (Poecilla reticulata), paramecium protozoan (Paramaecium caudatum) and the above-mentioned fairy shrimp. The investigation revealed that both dyes in concentrations used for hydrological purposes are low enough to exert almost no toxic impact on water fauna considered.

Though much is known about freshwater snail ecology, their circadian rhythms remain poorly investigated. Well-fed, stress-free, mid-size adults of six species common in central Italian lakes were exposed to natural sunlight and photoperiod, and their activity status was recorded at 3-h intervals during a 9-d indoor experiment. All species exhibited evident diurnal habits despite high individual variability, with midday-to-early-afternoon activity peaks. Activity was correlated with diel light conditions but not with short-term changes in albedo. The prosobranch Bithynia (=Codiella ) leachii and the pulmonates Physa (=Physella ) acuta and Planorbis planorbis were the most active species and exhibited the longest-lasting response to daytime food addition. The prosobranch Valvata piscinalis exhibited long periods retracted in its shell with the operculum shut, and the remaining taxa (the pulmonates Galba (=Lymnaea ) truncatula and Radix (=Lymnaea ) auricularia ) exhibited an intermediate degree of activity. P. acuta was the most active species at night and exhibited the quicker response to nighttime food addition. Alertedness to (diurnal) predators may be highest for the highly active P. acuta and P. planorbis , whose antipredator defenses are mainly behavioral. Diel activity patterns and other ecological characteristics suggest that P. acuta may be favored in food-rich habitats, while V. piscinalis may not be able to fully exploit food resources, especially if in limiting quantities. All snail species – and P. acuta in particular – may stimulate periphyton metabolism while keeping its biomass low by grazing mainly during the time of maximum photosynthesis.

The earliest ammonite species of Jurassic type, Psiloceras spelae GUEX, was unknown till 1998. This species bridges the long gap between the latest Triassic and the earliest Jurassic ammonoids. It was discovered in North America, then in South America and finally in Europe. The species is proposed as boundary marker for the base of the Jurassic system. It is known in two forms which are regarded as subspecies. The European subspecies is here introduced as P. spelae tirolicum n. ssp. This taxon occurs in the Northern Calcareous Alps of Tyrol as the oldest European Jurassic type ammonite. Both subspecies characterize the first Jurassic ammonite biohorizon and are closely related. Their slight differences may be due to biogeographic separation. The preservation admits a complete diagnosis of the new subspecies. Besides psiloceratid characters still phylloceratid characters are present indicating the origin of the psiloceratids. Additionally, slightly younger psiloceratids are described which were known only from South and North America thus far. They are older than the oldest psiloceratids hitherto known from Europe. All these forms are elements of the first biochronological ammonite unit of the Jurassic, the Tilmanni Chronozone which is situated below the Planorbis Chronozone. It is assumed that during the endTriassic biotic crisis only those ammonites survived which lived in the open parts of the oceans. A re-population of neritic shelf areas took place from the oceanic realms in line with the gradual Hettangian transgression. This may explain the global similarity of the first Jurassic ammonites and their later biogeographic diversification. A time calculation based on the sedimentation rate of the P. spelae tirolicum n. ssp. bearing sections leads to the conclusion that the earlier Triassic-Jurassic ammonite gap of about 250 to 300 ka now can be reduced to approximately 100 ka.

A survey of the larval stages (cercariae and metacercariae) of trematodes (Digenea) found in planorbid snails in Central Europe (Austria, Czech Republic, south-east Germany, Hungary, Poland and the Slovak Republic) is presented based on a study of 7,628 snails of 12 species examined between 1998-2006. A total of 34 trematode larval stages, comprising cercariae of 28 species and metacercariae of seven species (one species occurred both as cercaria and metacercaria) of nine families were found in 898 (11.5%) snails of eight species. The dominant cercariae were those belonging to the Rubenstrema exasperatum (Rudolphi, 1819)/Neoglyphe locellus (Kossack, 1910) species complex, Tylodelphys excavata (Rudolphi, 1803) and Echinostoma spiniferum (La Valette, 1855) sensu Nasincová (1992), all from Planorbarius corneus (Linnaeus). Almost the same spectrum of cercariae of the families Echinostomatidae, Plagiorchiidae and Omphalometridae was found in the present study as in previous reports; however, a considerably lower spectrum of cercariae of the families Diplostomidae and Strigeidae was recorded. The most frequent metacercariae were those of Echinoparyphium aconiatum Dietz, 1909, Neoglyphe locellus and Moliniella anceps (Molin, 1859), all occurring mainly in P. corneus. The most heavily infected snail species was P. corneus, followed by Planorbis planorbis (Linnaeus) and Segmentina nitida (Müller). The widest spectrum of trematode species was found in P. planorbis and P. corneus. Forty-two cercariae identified to the species level belonging to 15 families, plus an additional 43 taxa recorded under generic or provisional names, were reported from 11 species of planorbids in previous studies carried out in Central Europe. However, the actual number of trematode species occurring in the planorbid snails is probably much lower, because many, if not most, larval stages reported under provisional names or unidentified to the species level may be conspecific with identified adult forms. A key to the cercariae and metacercariae recorded from planorbids in Central Europe, together with illustrations of those species encountered most frequently in the field, is provided to facilitate identification.

A high-resolution palaeoecological study of the shelly invertebrate macrofauna across two marine Triassic–Jurassic boundary sections in the UK (St. Audrie9s Bay and Lavernock Point) is presented. Loss of taxonomic richness occurs in the upper Westbury Formation to lower Lilstock Formation (late Rhaetian), but if sample size is taken into account there is little convincing evidence of a catastrophic marine extinction. There is, however, good evidence for significant palaeoecological change in the benthic marine ecosystem at this time. The immediate post-event recovery interval in the upper Lilstock Formation is characterized by assemblages of low abundance, low diversity, high dominance and low evenness. Body-sizes of taxa that survived the event and originated afterwards were low until the later Hettangian. Recovery to higher abundance, higher diversity and higher evenness is recorded in the Psiloceras planorbis Zone. Recovery of the benthic ecosystem in the aftermath of the Late Triassic event was disrupted by marine anoxia and shows additional similarities to the (much slower) recovery that followed the Late Permian event. The pattern of body-size changes recorded in the shelly fossil record closely matches that of the trace fossil record. Shell thickness trends do not support a biocalcification crisis during the Late Triassic biotic event.

Approximately 40% of a skeleton including cranial and postcranial remains representing a new genus and species of basal neotheropod dinosaur is described. It was collected from fallen blocks from a sea cliff that exposes Late Triassic and Early Jurassic marine and quasi marine strata on the south Wales coast near the city of Cardiff. Matrix comparisons indicate that the specimen is from the lithological Jurassic part of the sequence, below the first occurrence of the index ammonite Psiloceras planorbis and above the last occurrence of the Rhaetian conodont Chirodella verecunda. Associated fauna of echinoderms and bivalves indicate that the specimen had drifted out to sea, presumably from the nearby Welsh Massif and associated islands (St David’s Archipelago). Its occurrence close to the base of the Blue Lias Formation (Lower Jurassic, Hettangian) makes it the oldest known Jurassic dinosaur and it represents the first dinosaur skeleton from the Jurassic of Wales. A cladistic analysis indicates basal neotheropodan affinities, but the specimen retains plesiomorphic characters which it shares with Tawa and Daemonosaurus.

The invasive ascidian, Didemnum sp. A, first appeared in New England bays and harbors in the early 1990s, and in the waters around Cape Cod in 1993. While ship traffic was the likely vector introducing the species, its origin and precise date and location of its introduction are presently unknown. Colony surfaces of Didemnum sp. A appear very clean and not favorable substrates for epibiota settlement, but closer inspection revealed the presence of benthic foraminifera. During 2003 and 2004, 52 samples of Didemnum sp. A and other ascidians were collected to determine whether or not the foraminiferal assemblages might also be non-native and thus provide a potential clue to the place of origin of Didemnum sp. A. Sample locations included the New England coast from Connecticut to Maine (with a concentration in the Cape Cod area), northern California, Zeeland, The Netherlands, and Shakespeare Bay, New Zealand. From New England samples, 18 species of benthic foraminifera were identified. The most common species represented were Cornuspira involvens, C. planorbis, Elphidium galvestonense, E. margaritaceum, Glabratellina lauriei, Miliolinella subrotunda, Quinqueloculina bicornis, and Rosalina floridana. Foraminiferal assemblages on Didemnum sp. A from other regions sampled were composed of the same cosmopolitan species found in New England, plus other species which were indigenous to each region. Because no exotic foraminifera species were found it is concluded that Didemnum sp. A likely did not introduce non-native foraminifera originating from their native habitats into the New England region.

International audience; Most venomous predators have evolved complex venom primarily to immobilize their prey and secondarily to defend against predators. In a new paradigm, carnivorous marine gastropods of the genus Conus were shown to rapidly and reversibly switch between two types of venoms in response to predatory or defensive stimulus, suggesting that the defensive use of venom may have a more important role in venom evolution and specialization than previously thought. To further investigate this phenomenon, the defensive repertoire of a vermivorous species, Conus planorbis, was deciphered using second-generation sequencing coupled to high-throughput proteomics. The venom gland transcriptome of C. planorbis revealed 182 unique conotoxin precursors from 25 gene superfamilies, with superfamily T dominating in terms of read and paralog numbers. Analysis of the defense-evoked venom revealed that this vermivorous species uses a similarly complex arsenal to deter aggressors as more recently evolved fish- and mollusk-hunting species, with MS/MS validating 23 conotoxin sequences from six superfamilies. Pharmacological characterization of the defensive venom on human receptors identified the nicotinic acetylcholine receptors as a primary target. This work provides the first insights into the composition and biological activity of specifically evolved defensive venoms in vermivorous cone snails.

Changes in benthic foraminiferal and mollusk assemblages from the lower part of the Upper Pliocene of the Atsipades Section (Iraklion Basin, central Crete) were studied. The Atsipades Section represents a shallowing-upward sequence from outer shelf blue–gray clays at the bottom of the sequence, deposited below the storm wave base, to shallow inner shelf deposits affected by storm waves at the top. The foraminiferal assemblage at the bottom of the sequence is dominated by Bolivina spathulata , Bolivina dilatata and Uvigerinidae, a microfossil assemblage corresponding to the deepest deposits formed under dysoxic sea-floor conditions. Foraminiferal assemblages of the middle part of the section are highly diversified, predominantly Haynesina depressula , Cassidulina carinata and Reusella spinulosa . The top of the section is mainly characterised by Asterigerinata planorbis , Bolivina pseudoplicata , Cibicides lobatulus and Elphidium sp., a typically epiphytic foraminiferal assemblage which can be correlated with the presence of an algal covered sea-bottom. Within this general environmental trend, a minor shallowing cycle can be differentiated. The boundaries of this cycle can be inferred, based on a substantial microfossil assemblage change and on the coincidence of species diversity maximum and a planktonic/benthic (P/P + B) ratio peak. Nonetheless, upwelling currents and/or over-abundance of nutrients due to continental outflow could also contribute to increased diversity and P/P + B ratio. The character of the mollusk assemblages is in accordance with these trends. Moreover, the increase in diversity and in sculpture constitutes a clear indication of an increase in hydrodynamic energy related to a shallowing-upward trend.

In the course of two trips to Central America (June 1967 and JulyAugust 1976) I had the opportunity of collecting topotypic specimens of Planorbis nicaraguanus Morelet, 1849, anatomically defined in this paper, and of P. yzabalensis Crosse & Fischer, 1879, the identity of the latter with Drepanotrema anatinum (Orbigny, 1835) is confirmed. The following planorbid species were also found: Helisoma trivolvis (Say, 1817) in Nicaragua, Guatemala, Costa Rica and Belize; H. duryi (Wetherby, 1879) in Costa Rica; Biomphalaria helophila (Orbigny, 1835) in Guatemala, Belize, Nicaragua, Costa Rica and El Salvador; B. kuhniana (Clessin, 1883) in Panama; B. obstructa (Morelet,1849) in Guatemala, Belize and El Salvador; B. straminea (Dunker, 1848) in Costa Rica; B. subprona (Martens, 1899) in Guatemala; D. anatinum (Orbigny,1835) in Belize, Guatemala, Nicaragua and Costa Rica; D. depressissimum (Moricand,1839) in Nicaragua, Costa Rica and Panama; D. lucidum (Pfeiffer, 1839) in Guatemala, Belize and Nicaragua; D. surinamense (Clessin, 1884) in Costa Rica and Panama; and Gyraulus percarinatus sp. n. in Panama. The occurrence of B. kuhniana and D. surinamense is first recorded in Central America, and Gyraulus percarinatus is the first representative of the genus provenly occurring in the American continent south of the United States. The following synonymy is proposed: Planorbis declivis Tate, 1870 = Biomphalaria helophila (Orbigny, 1835); Planorbis isthmicus Pilsbry, 1920 = Biomphalaria kuhniana (Clessin, 1883); Planorbis cannarum Morelet, 1849 and Segmentina donbilli Tristram, 1861 = Biomphalaria obstructa (Morelet, 1849); and Planorbis yzabalensis Crosse & Fischer, 1879 = Drepanotrema anatinum (Orbigny, 1835), confirming Aguayo (1933).

In the course of a trip to Ecuador I had the opportunity of collecting topotypic specimens of the following nominal species of pulmonate molluscs: Biomphalaria cousini Paraense, 1966; Planorbis equatorius Cousin, 1887; P. canonicus Cousin, 1887; Lymnaea cousini Jousseaume, 1887 and P. boetzkesi Miller, 1879. Additional findings were: Helisoma trivolvis (Say, 1817), Biomphalaria peregrina (Orbigny 1835), Drepanotrema anatinum (Orbigny, 1835), D. kermatoides (Orbigny, 1835), D. lucidum (Pfeiffer, 1839), D. surinamense (Clessin, 1884), Lymnaea columella Say, 1817 and Physa acuta Draparnaud, 1805. P. boetzkesi and P. canonicus are considered junior synonyms of Gyraulus hindsianus (Dunker, 1848) and Biomphalaria peregrina (Orbigny, 1835), respectively.

Four freshwater pulmonate species (Lymnaea ovata, L. stagnalis, Physa acuta, Planorbis leucostoma)were living in several watercress beds known for their relationships with human cases of fasciolosis, whereas L. truncatula was never found. The aims of these studies were to determine the prevalence of natural infections with Fasciola hepatica in snails and to verify if these species might ensure the full larval development of this trematode (with cercarial shedding] when they were experimentally subjected to F. hepatica only, or to co-infections with an other trematode species. Investigations were so carried out in six snail populations living in watercress beds (including three for P. acuta) and in four others originating from three brooks or a pond (as controls). Snails naturally infected with F. hepatica were found in two watercress beds inhabited by L. ovata (prevalence of infection: 1.4 %) and P. leucostoma (0.1 %), respectively. The L. ovata from the watercress bed could be infected at a higher size than those from the control population and the prevalence of this infection was greater in the bed population. Similar findings were noted for L. stagnalis. Despite single or dual infections, the results obtained with the four populations of P. acuta were unsuccessful. In contrast, the co-infections of young P. leucostoma with Paramphistomum daubneyi and F. hepatica resulted in the shedding of some F. hepatica cercariae. According to the authors, the occurrence of fasciolosis in these watercress beds would be the consequence of frequent natural encounters between parasite and snails (L. ovata, L. stagnalis), or of co-infections with P. daubneyi and F. hepatica (P. leucostoma). In watercress beds only colonized by P. acuta, a lymnaeid species would have ensured the larval development of F. hepatica but it would have been eliminated by P. acuta, as this last species was known to be invasive and could colonize open drainage ditches on siliceous soil.

The paper is the first illustrated check-list of the freshwater Gastropoda of the state of Mongolia. The authors examined their own samplings made in 2009–2012 as well as collections of other explorers and zoological museums (mostly those of Russia). In total, 35 nominal species of four families (Valvatidae, Lymnaeidae, Physidae, and Planorbidae) have been included into annotated list, with remarks on their distribution, ecology, taxonomic status, and nomenclature. All species are illustrated by pictures of their shells (including some type specimens). The fauna of freshwater Gastropoda of Mongolia is taxonomically impoverished as compared to the fauna of southern Siberia and other adjacent areas. In particular, no representatives of such families as Acroloxidae and Bithyniidae were found to live there as well as no species of Anisus, Aplexa, Planorbarius, Planorbis, Stagnicola and some other genera of aquatic snails broadly distributed in Palearctic. From the zoogeographic point of view, the recent fauna of aquatic Gastropoda of Mongolia consists of species belonging to three diversification centers—northwestern Palearctic, Siberian, and Central-South Asian. The only species endemic to Mongolia is Choanomphalus mongolicus inhabiting the Hövsgöl Lake. A brief history of formation of the recent Mongolian fauna of freshwater snails is provided.

The present study spotted some light on human fascioliasis in Kafr El-Sheikh Governorate in the west of the Nile Delta in Egypt, its species, its intermediate host (IMH) snail and tried to answer previous questions about development of Fasciola (F.) species in new snail hosts other than that known for animal fascioliasis in Egypt. The study recorded a percentage of infection by Fasciola eggs reached up to 6.02% in 1810 randomly collected human stool samples from 6 climatically selected sites in this governorate using fluke-finder technique. The incidence was high in Sedi Salem and Motobus than in the other study sites. Micrometry measuring of 100 eggs from each locality showed that egg size cannot be used as a main criterion in differentiation between F. hepatica and gigantica. Wide range of egg size varied between 130-162.5 µ X 75-87.5 µ with a mean length and width of 144.24 ± 11.33 µ X 80± 6.55µ, was recorded. Upon dissection of 1972 Lymnaea (L.) cailliaudi, 268 L. alexandrina, 502 Bulinus species, 11316 Biomphalaria alexandrina, 1398 Cleopatra species, 8520 Physa acuta, 420 Melania tuberculata, 2132 Vivipara (Bellamya) unicolar, 144 Neritina nilotica and 1570 Planorbis philippi, Fasciola parthenitae were not detected in snails other than L. cailliaudi (the known IMH of Fasciola in Egypt). The results proved that there is no accommodation has occurred in any of the surrounding snails to transmit Fasciola to man. The present study proved that human fascioliasis in the study sites was due to Fasciola gigantica not F. hepatica. This appeared in its tendency to develop in L. cailliaudi not in other tested snails with successive radial generations as that described previously for F. gigantica. Moreover, early mature flukes extracted from laboratory infected rabbits by the produced encysted metacercariae had the characteristic features described previously for F. gigantica.

Planorbis varians Fuchs, 1870 —how to recombine? Planorbis varians Fuchs, 1870 in Fuchs 1870a: 356, pl. 14, figs 1–9. Gyraulus (Gyraulus) varians (Fuchs): Wenz 1923: 1622 (cum syn.). Muellerpalia varians (Fuchs, 1870); Bandel 2010: 104 [not pl. 8, figs 90–94, = Muellerpalia bicincta (Fuchs, 1870)]. Marinescugyra varians (Fuchs, 1870); Bandel 2010: 112, pl. 13, figs 153–158. In his revision about the valvatiform gastropods of the Paratethys realm, Bandel (2010) introduced amongst others the genera Muellerpalia (Hydrobiidae) and Marinescugyra (Planorbidae), based on characteristic protoconch features. One of the discussed species is Planorbis varians Fuchs, 1870 from Rădmăneşti in Romania. On the grounds of different protoconch properties, Bandel assigned specimens, putatively belonging to the same species, to either Muellerpalia (p. 104) or Marinescugyra (p. 112). For the latter, it even constitutes the type species. Hence, Bandel used two different combinations based on the same original combination. From a nomenclatural as well as a taxonomic view this is of course not tenable. It means that either the various specimens belong to two different species or the diagnostic features of the two genera are not meaningful. The associated problems were clear to the author as became evident from personal correspondence: Bandel (pers. comm.) stated the possibility that " Planorbis varians " is actually represented by two species, which would have to be assigned variably to Muellerpalia or Marinescugyra based on their protoconchs. Unfortunately, this discussion is wanting in the paper. However, it turned out that the two combinations indeed refer to different species. The specimens illustrated by Bandel (2010) as " Marinescugyra varians " (pl. 13, figs 153–158) undoubtedly refer to the same species as described by Fuchs (1870a). They correspond in the two strong keels, the intermediate spiral lines, the slightly concave umbilical part, and the weakly stepped funnel-like apical part. In contrast, the individuals depicted as " Muellerpalia varians " (Bandel 2010, pl. 8, figs 90–95) belong to a different species: they have both keels on the umbilical side, apparently lack additional spiral lines, have highly convex whorls, and more distinct growth lines. Direct comparison of the descriptions and illustrations of Fuchs (1870a, b) and Bandel (2010) suggest that Bandel confused several species. Firstly, " Muellerpalia varians " sensu Bandel rather corresponds to " Valvata bicincta Fuchs, 1870 " in Fuchs (1870b) [= Muellerpalia bicincta (Fuchs, 1870)]. Secondly, specimens illustrated as " Muellerpalia bicincta " by Bandel rather resemble " Valvata carinata Fuchs, 1870 " in Fuchs (1870b) [= Muellerpalia carinata (Fuchs, 1870)]. Conversely, Muellerpalia carinata (Fuchs, 1870) sensu Bandel, 2010 may represent Muellerpalia bicincta. The new combinations of both latter taxa with the new genus Muellerpalia still remain valid. The presence of a second, fainter keel on the umbilical side in " Muellerpalia varians " sensu Bandel (2010) [= Muellerpalia bicincta (Fuchs, 1870)], which is not discernible in the original material of Fuchs (1870a), is regarded as intraspecific variability herein, as all other features correspond quite well. Unfortunately, Bandel did not provide an illustration of the apical region, which would show a distinct keel if our determination as M. bicincta is correct. Nevertheless, the endpoint of keel-like structure is visible in the apertural view (Bandel 2010, pl. 8, fig. 94). Even if it might turn out that this tentative placement is wrong, it still remains well separated from Marinescugyra varians. In conclusion, the genus Marinescugyra, with Planorbis varians Fuchs, 1870 as type species, remains valid and the combination Marinescugyra varians (Fuchs, 1870) is the only accepted one. The combination Muellerpalia varians (Fuchs, 1870) is based on a misidentification of the species. We tentatively synonymize this record with Muellerpalia bicincta (Fuchs, 1870)., Published as part of Neubauer, Thomas A., Harzhauser, Mathias, Georgopoulou, Elisavet, Mandic, Oleg & Kroh, Andreas, 2014, Replacement names and nomenclatural comments for problematic species-group names in Europe's Neogene freshwater Gastropoda, pp. 453-468 in Zootaxa 3785 (3) on pages 464-465, DOI: 10.11646/zootaxa.3785.3.7, http://zenodo.org/record/4913363, {"references":["Fuchs, T. (1870 a) III. Beitrage zur Kenntniss fossiler Binnenfaunen. III. Die Fauna der Congerienschichten von Radmanest im Banate. Jahrbuch der k. k. geologischen Reichsanstalt, 20, 343 - 364.","Wenz, W. (1923 - 1930) Fossilium Catalogus I: Animalia. Gastropoda extramarina tertiaria. W. Junk, Berlin, I: pp. 1 - 352 (1923), II: pp. 353 - 736 (1923), III: pp. 737 - 1068 (1923), IV: pp. 1069 - 1420 (1923), V: pp. 1421 - 1734 (1923), VI: pp. 1735 - 1862 (1923), VII: pp. 1863 - 2230 (1926), VIII: pp. 2231 - 2502 (1928), IX: pp. 2503 - 2886 (1929), X: pp. 2887 - 3014 (1929), XI: pp. 3015 - 3387 (1930).","Bandel, K. (2010) Valvatiform Gastropoda (Heterostropha and Caenogastropoda) from the Paratethys Basin compared to living relatives, with description of several new genera and species. Freiberger Forschungshefte: Palaontologie, Stratigraphie, Fazies, C 536, 91 - 155.","Fuchs, T. (1870 b) VII. Beitrage zur Kenntniss fossiler Binnenfaunen. IV. und V. Die Fanna der Congerienschichten von Tihany am Plattensee und Kup bei Papa in Ungarn. Jahrbuch der k. k. geologischen Reichsanstalt, 20, 531 - 548."]}

The commonly reported freshwater snail Ceratophallus natalensis (Krauss) (Planorbidae) of eastern and southern Africa is shown here to be a composite taxon comprising at least three species. The species of Ceratophallus are found only in Africa and some Indian Ocean islands; they are distinguished by the structure of the penis, which is chitinized internally and may bear microspination. Ceratophallus natalensis (Krauss) has been often recorded as common in pools and marshes. According to observations on the genital organs reported here, this taxon comprises three species, C. natalensis , C. gibbonsi (Nelson) comb. nov. and C. yesimit sp. nov. No clear-cut conchological differences among them were evident. Anatomical observations were made on snails from 398 collectors' samples, providing many new locality records for this genus (details in Appendix). Ceratophallus natalensis and C. gibbonsi are widespread from Ethiopia to South Africa, whereas C. yesimit is known only from the Ethiopian Rift Valley. Though natalensis and gibbonsi are partly sympatric, the latter is associated with fully tropical climatic areas and comparatively permanent waterbodies, whereas natalensis is commonest in cooler areas and is abundant in seasonal rain pools. This study showed the penis of Ceratophallus to be stiffened by internal chitinous bands that apparently are unique in the Planorbidae and perhaps for all pulmonate molluscs. It is suggested that the microspinous penis of C. natalensis may be adapted to the function of sperm displacement. The chromosome number 2 n =36 was observed for C. natalensis . Comparative data are given for Afrogyrus coretus (de Blainville) (Planorbidae), which in part of its range is sympatric with Ceratophallus and has a similar shell, but differs in having an external penial stylet. Although both groups are found only in the Afrotropical Region, they apparently differ in biogeographical history and phylogeny. In a cladogram where the first apomorphy is external chitinization of the penis, Afrogyrus is allied to Gyraulus , whereas Ceratophallus is more closely related to Planorbis .