Studies in Canarium urceus (Linnaeus, 1758) Part 6: A new Canarium species from the Andaman Sea (Gastropoda: Strombidae) and discussion on related species

This part of the Canarium (Canarium) urceus-complex (Linnaeus, 1758) review after Abbott’s revision (Abbott, 1960) revision examines material from the Andaman Sea. At present, material from that region has been synonymised under the name Canarium (Canarium) urceus (Linnaeus, 1758). Canarium (Canarium) andamanense new species is known from the Andamanian Subprovince, a semi enclosed basin that is centered on the Andaman Sea and enclosed by the west coasts of Myanmar and Thailand and the Mergui Archipelago in the east, to the northern Malacca Strait in the south, and to the Andaman and Nicobar Islands in the west. This species is recognized and differentiated by solid, sturdy shells with a triangular body whorl, large knobs on the shoulder and bright orange aperture. This study further confirms that there is a high degree of bioregionalisation within the Canarium complex.

A new species of Solaropsis Beck, 1837 (Gastropoda: Stylommatophora: Solaropsidae) from the Brazilian Amazon

A specimen of Solaropsidae from the collection of the Academy of Natural Sciences of Drexel University (Philadelphia, USA) was recognised as a potential new species based on shell morphology. With support from a multi-locus molecular phylogenetic analysis, a new species is described here: Solaropsis penthesileae sp. nov. It is native to the Amazon Rainforest in Pará state, northern Brazil, and it is closely related to S. nimbus (Simone). It differs in its more discoid shell, with a wider body whorl that bears a stronger median angulation in its lower spire. The specimen was collected in 1998 and is an example of the long shelf-life invertebrates may have in museum collections before they are identified and formally described. It is also a reminder of the importance of those collections for biodiversity studies.

Varadia, a new helicarionoidean semi-slug genus from India’s Western Ghats (Stylommatophora: Helicarionoidea)

We here describe a new Indian helicarionoidean genus, Varadia Bhosale & Raheem gen. nov., containing the single species Varadia amboliensis Bhosale, Thackeray, Muley & Raheem gen. et sp. nov. This new semi-slug is endemic to the northern and central Western Ghats and is primarily a forest-living species. We describe and figure the shell, reproductive system, radula, spermatophore and external morphology of this new species, and detail its known distribution. We explore its relationships to other helicarionoideans using phylogenetic analyses of DNA sequence data for part of the ribosomal RNA gene cluster and discuss the morphology of the new genus in relation to other, primarily South Indian, helicarionoidean taxa. Based on characters of the reproductive system, particularly the male genitalia and the gametolytic sac, we provisionally place Varadia gen. nov. in the Macrochlamydinae (Ariophantidae). This is consistent with the results of our molecular phylogenetic analyses. The combination of large size, broad, densely tuberculated shell lobes and a shell with ca 4 whorls and a disproportionately large body whorl makes V. amboliensis gen. et sp. nov. unique among the helicarionoidean taxa of the Western Ghats. The new semi-slug is also highly distinctive in the morphology of its male genitalia.

Chloritis caseus (Pfeiffer, 1860): a newly recorded species for the fauna of Vietnam (Mollusca: Gastropoda: Camaenidae)

The genus Chloritis H. Beck, 1837 comprises 160 species in the world and is restricted to South-east Asia with numerous species having usually small distributional ranges. There were eight Chloritis species discovered in Vietnam. Specimens of Chloritis caseus (Pfeiffer, 1860) have been found in Dak Lak Province as a new record for the fauna of Vietnam, thus so far, there is a total of nine species of the genus Chloritis reveated for terrestrial molluscs of Vietnam. Chloritis caseus has some the following characters as: shell medium, dextral, yellowish-brown in colour; shell rather flat with slightly elevated spire; body whorl keeled, somewhat shouldered due to slight depression from ventrolateral direction; whorls 4½, convex, separated by impressively deep suture; approximately quarter of the last whorl turns obliquely downwards, so the aperture is directed toward umbilicus; aperture rounded, peristome expanded, reflexed and thickened; parietal callus present only; umbilicus open.

Two new stygobiotic species of Horatia Bourguignat, 1887 (Hydrobiidae) from Croatia

In this paper we describe two new species of the freshwater snails of genus Horatia. A new stygobiotic species of Horatia Bourguignat, 1887 is described from Izvor Beguša in Croatia. It occurs in sympatry with the crenobiotic H. klecakiana Bourguignat, 1887, but is morphologically and molecularly distinct. It is characterized by the terminal part of the body whorl separated from the columella, and neither eyes nor any pigment on the soft parts. It is a stygobiont gastropod, known so far only from one living specimen and several empty shells, thus its soft part morphology and anatomy remain unknown. Another new species of stygobiotic Horatia was found inside the cave Mali Rumin, its description is based solely on numerous empty shells from the cave sediments.

Sexual dimorphism in shell morphology of mollusks of the genus Viviparus – important objects of water resources of Ukraine

Bioindication assessment of water bodies of Ukraine can be carried out using the ratio of males and females of mollusks of the genus Viviparus. In practice, it is very convenient to determine the sex of mollusks by the differences in their shell. Male and female freshwater snails Viviparus viviparus (Linnaeus, 1758) and V. contectus (Millet, 1813) are shown to have reliable differences in shell morphology depending on their age. There is almost no sexual dimorphism by shell morphometrics and indices in Viviparus snails aged one to three years. After three years of life, mature females have significantly larger shell width, higher body whorl, and size of the aperture. Females of V. viviparus at the age of two to five years may be differentiated from males by the relationship of mean shell width and shell height, which is statistically significant higher than in males. This difference is explained by the different size of the mantle section genital organs of mature male and female. The obtained results should be taken into consideration in establishing the sex of viviparid snails.

A new subspecies of microsnail from Masungi Georeserve, Rizal, Philippines

A new subspecies of microsnail, Hypselostoma latispira masungiensis subsp. nov., is described based on shell morphology and molecular characters. This new subspecies is distinguished from H. l. latispira from Baguio City, Benguet Province by having relatively larger major width size, additional apertural teeth (interpalatal plica), larger body whorl and apertural width, and clustering based on location. The collected samples from Masungi Georeserve, Rizal Province appear to be an ecophenotype as indicated by the novel site congruent to the clade separation of Masungi and Baguio H. latispira. Neighbor-joining and maximum likelihood trees also demonstrated that the two sample groups clustered separately, with bootstrap support of 84% and 78%, respectively. However, pairwise distance comparison revealed that there is only an average of 0.0131 ± 0.0126 genetic distance (99.98%) between the two populations, suggesting that they are most likely similar species; thus, the proposal of making it a subspecies. This is the first report on the new distributional record outside the type locality and a new subspecies of H. latispira. KEYWORDS: land snail, karst, interpalatal plica, pairwise distance comparison

An unusually sculptured new species of Phreatodrobia Hershler & Longley (Mollusca: Caenogastropoda: Cochliopidae) from central Texas

There are eight described species in Phreatodrobia, minute, phreatic (subterranean aquatic) snails, all stygobitic and endemic to the Edwards-Trinity Aquifer System of Texas. Two species were described from river drift (Pilsbry & Ferriss 1906) and the others more recently by sampling the water flowing from wells or springs (Hershler & Longley 1986b; Hershler & Longley 1987). Recent sampling from spring orifices and the hyporheic zone of streams have extended the known ranges of the phreatic snails of the region and encountered unknown snails (Alvear et al. 2020). Here we describe Phreatodrobia spica n. sp., a rarely encountered species with a large range of about 400 km (Figure 1). We find P. spica in samples with a diverse assemblage of phreatic animals including other species of Phreatodrobia, isopods, amphipods, coleopterans, and mites. Phreatodrobia spica is distinguished from congeners using morphological and molecular evidence and is characterized by an elevated, trochiform shell with unique sculpture that include spikes and pustules. It has an open umbilicus and a complete, reflected lip that is sometimes appressed to the body whorl.

Preliminary investigation demonstrating the GHITM gene probably involved in apoptosis and growth of the golden apple snail (Pomacea canaliculata)

Background Growth hormone inducible transmembrane protein (GHITM) is a highly conserved transmembrane protein. This study was conducted to investigate the role of GHITM gene in the apoptosis and growth of the golden apple snail Pomacea canaliculate. Results The complete cDNA of this gene was cloned using the rapid amplification of cDNA ends (RACE) method and subjected to bioinformatics analysis. The full-length cDNA was 2242 bp, including an open reading frame of 1021 bp that encoded a protein of 342 amino acid residues. The mRNA expression profiles of GHITM gene in different tissues (liver, kidney, gonad and foot) and different growth phases (6-months old and 2-years old) showed that it was expressed in various tissues and different growth phases. Silencing of the GHITM gene by RNAi (RNA interference) experiments revealed that the GHITM gene possibly plays a role in inhibiting apoptosis through detecting the Caspase (Cysteine-requiring Aspartate Protease)-3 activity. In addition, the aperture width and body whorl length of the snail was significantly affected by RNAi, suggesting that this gene plays a significant role in promoting the growth of the organism. Conclusions These results demonstrated that the GHITM gene was involved in apoptosis and growth in golden apple snail.

Shell Morphology, Radula and Genital Structures of New Invasive Giant African Land Snail Species, Achatina fulica Bowdich, 1822,Achatina albopicta E.A. Smith (1878) and Achatina reticulata Pfeiffer 1845 (Gastropoda:Achatinidae) in Southwest Nigeria

The aim of this study was to determine the differences in the shell, radula and genital structures of 3 new invasive species, Achatina fulica Bowdich, 1822,Achatina albopicta E.A. Smith (1878) and Achatina reticulata Pfeiffer, 1845 collected from southwestern Nigeria and to determine features that would be of importance in the identification of these invasive species in Nigeria. This is the first report of Achatina albopicta and A. reticulata in Nigeria, but Achatina fulica have since been reported in Nigeria and other African countries outside coastal East Africa. No study has described the external or internal morphology of any of the invasive species in Nigeria. Five to ten live specimens of each species, with complete shell characters, of each species were used for this study. Vernier caliper was used to obtain all shell measurements, with the shell held vertically and the aperture facing the observer. The genital structures were dissected out and fixed in 70% alcohol for 10-15 minutes and examined. The buccal mass was dissected out and digested in 7.5% sodium hydroxide for 24 hrs to free the radula from snail tissues and then examined under the compound microscope.The shells of the 3 new species were dextral, conical with pointed spire and narrow apex. The whorls were separated by deep sutures. The parietal walls and the columella of the three species were white but columella of A. reticulata had a characteristic thick deposit of white porcelain-like material. There were dark brown markings on the whorls of the three species on dirty brown background for A. fulica and A. reticulata and dirty yellowish background for A. albopicta. The shell of A. albopicta was slightly glossy on the body whorl. The whorls of A. albopicta were much more convex than the whorls of A. fulica and A. reticulata. The columella of A. albopicta was truncate above the base of the peristome, moderately concave and slightly curved up at the base, while the columella of A. fulica was truncate sharply at the base of the peristome and straight and the columella of A. reticulata was slantly truncate at the base of the peristome and straight. The genitalia of the three species were very identical but differed slightly in the emergence of the basal vas deferens from the penis. The penes were slender and completely enclosed by the penial sheaths. The length of the penis varied from 10 to 12 mm. The vas deferens, free oviduct and the spermatheca duct were very long. The radula could be differentiated by the structure of central teeth and the first lateral tooth. The study showed that the shell morphology, radula and genital structures can be of importance in the identification of members of the family Achatinidae in Nigeria.