Morphometrics and phylogeography of the cave-obligate land snail Helicodiscus barri (Gastropoda, Stylommatophora, Helicodiscidae)

Molecular studies have recently led to the detection of many cryptic species complexes within morphologically ambiguous species formerly undescribed by the scientific community. Organisms such as land snails are at a particularly higher risk of species misidentification and misinterpretation, in that gastropod systematics are based almost entirely on external shell morphology. Subterranean ecosystems are associated with especially high degrees of cryptic speciation, largely owing to the abiotic similarities of these systems. In this study, we attempt to diagnose the potential cryptic diversity in the troglobitic land snail Helicodiscusbarri. Land snails are generally associated with having low vagility, and as such this species’ broad, mosaic distribution indicates the misdiagnosis of this organism as a single species. We analyze both mitochondrial (16S, CO1) and nuclear (28S, H3) genetic data for 23 populations. Phylogeny for H.barri was reconstructed using both maximum-likelihood and Bayesian approaches to assess relationships among populations, and two species delimitation methods (mPTP and ABGD) were used to detect the presence of unique molecular operational taxonomic units (MOTUs). Species delimitation results revealed seven and sixteen MOTUs respectively, suggesting the presence of several cryptic lineages within H.barri. To assess how external shell morphology corresponds with patterns of genetic and environmental variation, two morphometric approaches were used incorporating 115 shells from 31 populations. Both morphometric approaches reveal a significant environmental influence on shell morphology, and one approach showed the significance of MOTU groups. We discuss the delimitation and morphometric results and additionally provide discussion on the taxonomic and conservation implications of this study.

Download Full-text

Land snail genus Sarika Godwin-Austen, 1907 (Eupulmonata: Ariophantidae) from Cambodia, with description of three new species

European Journal of Taxonomy ◽

10.5852/ejt.2020.674 ◽

2020 ◽

Author(s):

Arthit Pholyotha ◽

Chirasak Sutcharit ◽

Phanara Thach ◽

Samol Chhuoy ◽

Pen Bun Ngor ◽

...

Keyword(s):

New Species ◽

Land Snail ◽

Land Snails ◽

Shell Morphology ◽

Taxonomic Position ◽

Knowledge Gap ◽

Taxonomic Descriptions ◽

The Status ◽

Reproductive Anatomy ◽

Three New Species

Taxonomic work on the land snail genus Sarika Godwin-Austen, 1907 in Cambodia is scarce. A total of three species were recognized from Cambodia prior to this study. However, their taxonomic descriptions were based mainly on shell morphology, with limited genital data. To address this knowledge gap, we opportunistically surveyed for land snails in Cambodia. Our inventory yielded four species of Sarika – one recognized species, Sarika bocourti (Morelet, 1875), from Battambang Province and three new species, Sarika khmeriana Pholyotha & Panha sp. nov., Sarika lactoconcha Pholyotha & Panha sp. nov. and Sarika nana Pholyotha & Panha sp. nov. from Kampot and Takeo Provinces in southern Cambodia. Our discovery involves the first species of Sarika to be described from Cambodia in more than a century highlights the extent to which the diversity of Cambodian land snails remains to be discovered. The status of two species, Sarika benoiti (Crosse & Fischer, 1863) and Sarika resplendens (Philippi, 1846), is at present ambiguous because no material identifiable as these species was found in recent extensive surveys. Although S. bocourti was recently collected from Cambodia, its taxonomic position remained unclear due to a lack of living specimens. Detailed descriptions and illustrations of living animals, shell morphology and reproductive anatomy are provided, and a map showing their distributions is given.

Download Full-text

Land snail fauna in Gunung Kuang Limestone Hill, Perak, Malaysia and its conservation implications (Mollusca, Gastropoda)

ZooKeys ◽

10.3897/zookeys.769.25571 ◽

2018 ◽

Vol 769 ◽

pp. 1-11

Author(s):

Chee-Chean Phung ◽

Yuen-Zhao Yong ◽

Mohamad Afandi Mat Said ◽

Thor-Seng Liew

Keyword(s):

Conservation Management ◽

Land Snail ◽

Management Plan ◽

Land Snails ◽

Snail Species ◽

Conservation Implications ◽

Species Checklist ◽

Unique Species ◽

Limestone Hill

This paper presents the first land snail species checklist for Gunung Kuang (Kuang Hill), a limestone hill located next to Gunung Kanthan that is recognised as one of the most important limestone hills for its diverse land snail fauna in Kinta Valley. Samplings were carried out at five plots in Gunung Kuang. This survey documented 47 land snail species, in which six species were identified as unique to Gunung Kuang. Approximately half of the land snails from Gunung Kanthan were found in Gunung Kuang. In addition, one of six unique species from Gunung Kanthan was also found in Gunung Kuang. These rich land snail species in Gunung Kuang are similar to other hills in Kinta Valley, but it is relatively lesser than the adjacent Gunung Kanthan. In view of Gunung Kuang’s unique land snail species, and its location closest to disturbed Gunung Kanthan, Gunung Kuang should be considered in the conservation management plan for Gunung Kanthan.

Download Full-text

Molecular phylogenetics of the land snail genus Quistrachia (Gastropoda : Camaenidae) in northern Western Australia

Invertebrate Systematics ◽

10.1071/is13045 ◽

2014 ◽

Vol 28 (3) ◽

pp. 244 ◽

Cited By ~ 5

Author(s):

Caitlin O'Neill ◽

Michael S. Johnson ◽

Zoë R. Hamilton ◽

Roy J. Teale

Keyword(s):

Western Australia ◽

Molecular Phylogenetics ◽

Taxonomic Status ◽

Land Snail ◽

Land Snails ◽

Shell Morphology ◽

New Genera ◽

Mtdna Sequences ◽

Additional Species ◽

Morphological Taxonomy

Recent collecting in the remote Pilbara region of Western Australia has revealed substantial increases in the apparent distributions of species of the genus Quistrachia, and the discovery of new forms, raising questions about the morphological taxonomy. To resolve these questions, we examined mtDNA sequences in all known species of Quistrachia, the unidentified new forms and other members of the subfamily Sinumeloninae. Phylogenetic analysis confirmed the monophyly of Quistrachia, including one of the new forms. The two other new forms represent new genera within the Sinumeloninae. Monophyly of each species was confirmed, with the exception of Q. legendrei, in which populations from the Dampier Archipelago and those from the adjacent Burrup Peninsula are in separate clades. Based on phylogeny and levels of divergence within other species in the genus, the Burrup populations appear to be conspecific with Q. turneri. This is supported by anatomical comparisons, but not by shell morphology, which may well reflect the evolutionary plasticity of shell form. Given the patchiness of searches for land snails in the largely inaccessible Pilbara region, additional species almost certainly remain to be discovered. Our study shows the value of including molecular analyses in determining the taxonomic status of new forms.

Download Full-text

Tracking parallel adaptation of shell morphology through geological times in the land snail genus Pupilla (Gastropoda: Stylommatophora: Pupillidae)

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlaa057 ◽

2020 ◽

Author(s):

Martin Haase ◽

Stefan Meng ◽

Michal Horsák

Keyword(s):

Morphological Changes ◽

Land Snail ◽

Land Snails ◽

Shell Morphology ◽

Shell Shape ◽

Ecological Niches ◽

Habitat Requirements ◽

Stochastic Nature ◽

Niche Shifts ◽

Molecular Phylogenetic

Abstract Changing environmental conditions force species either to disperse or to adapt locally either genetically or via phenotypic plasticity. Although limits of plasticity can be experimentally tested, the predictability of genetic adaptation is restricted due to its stochastic nature. Nevertheless, our understanding of evolutionary adaptation has been improving in particular through studies of parallel adaptation. Based on molecular phylogenetic inferences and morphological investigations of both recent and fossil shells we tracked the morphological changes in three land snails, Pupilla alpicola, Pupilla loessica and Pupilla muscorum. These species differ in habitat requirements as well as historical and extant distributions with P. alpicola and P. loessica being more similar to each other than to P. muscorum. Therefore, we hypothesized, that the three species reacted independently and individually to the conditions changing throughout the Pleistocene, but expected that changes within P. alpicola and P. loessica would be more similar compared to P. muscorum. Indeed, intraspecific shell shape differences across time were similar in P. alpicola and P. loessica, suggesting that similar niche shifts have led to similar transformations in parallel. In contrast, extant P. muscorum populations were practically identical in shape to their ancestors. They have probably tracked their ecological niches through time.

Download Full-text

Just the once will not hurt: DNA suggests species lumping over two oceans in deep-sea snails (Cryptogemma)

Zoological Journal of the Linnean Society ◽

10.1093/zoolinnean/zlaa010 ◽

2020 ◽

Vol 190 (2) ◽

pp. 532-557 ◽

Cited By ~ 1

Author(s):

Paul Zaharias ◽

Yuri I Kantor ◽

Alexander E Fedosov ◽

Francesco Criscione ◽

Anders Hallan ◽

...

Keyword(s):

Deep Sea ◽

Species Delimitation ◽

Molecular Data ◽

Shell Morphology ◽

Coi Gene ◽

Type Specimens ◽

Mitochondrial Coi ◽

Species Complexes ◽

Mitochondrial Coi Gene ◽

Taxonomic Studies

Abstract The practice of species delimitation using molecular data commonly leads to the revealing of species complexes and an increase in the number of delimited species. In a few instances, however, DNA-based taxonomy has led to lumping together of previously described species. Here, we delimit species in the genus Cryptogemma (Gastropoda: Conoidea: Turridae), a group of deep-sea snails with a wide geographical distribution, primarily by using the mitochondrial COI gene. Three approaches of species delimitation (ABGD, mPTP and GMYC) were applied to define species partitions. All approaches resulted in eight species. According to previous taxonomic studies and shell morphology, 23 available names potentially apply to the eight Cryptogemma species that were recognized herein. Shell morphometrics, radular characters and geographical and bathymetric distributions were used to link type specimens to these delimited species. In all, 23 of these available names are here attributed to seven species, resulting in 16 synonymizations, and one species is described as new: Cryptogemma powelli sp. nov. We discuss the possible reasons underlying the apparent overdescription of species within Cryptogemma, which is shown here to constitute a rare case of DNA-based species lumping in the hyper-diversified superfamily Conoidea.

Download Full-text

On the status of Rossmaessleria scherzeri scherzeri (Zelebor in Pfeiffer & Zelebor, 1867) (Gastropoda: Pulmonata: Helicidae)

Zootaxa ◽

10.11646/zootaxa.4286.1.7 ◽

2017 ◽

Vol 4286 (1) ◽

pp. 116

Author(s):

MARCO T. NEIBER

Keyword(s):

Species Delimitation ◽

Type Species ◽

Phylogenetic Analyses ◽

Single Species ◽

Distinct Species ◽

Molecular Data ◽

Land Snails ◽

North African ◽

The Status ◽

Mitochondrial Sequences

The genus Rossmaessleria Hesse, 1907, belonging to a mainly North African radiation of land snails assigned to the tribe Otalini (Helicidae: Helicinae, see Razkin et al. 2015 and Neiber & Hausdorf 2015) has recently been subject to two independent revisions (Walther et al. 2016; Torres Alba et al. 2016). Torres Alba et al. (2016) provided a detailed re-description of the type species of Rossmaessleria, R. scherzeri (Zelebor in Pfeiffer & Zelebor, 1867), including an anatomical investigation. Additionally, Torres Alba et al. (2016) provided new data on several Moroccan taxa belonging to the genus, e.g. R. tetuanensis (Kobelt, 1881) and R. olcesei (Pallary, 1899). Walther et al. (2016) revised the taxa included in Rossmaessleria on the basis of an examination of all available type material and newly collected specimens and described several, conchologically distinct new taxa. These authors also examined genital anatomy, conducted phylogenetic analyses on the basis of mitochondrial sequences and used species delimitation approaches based on their molecular data, concluding that several conchologically distinct lineages can be recognized in Rossmaessleria, but that anatomical and genetic differentiation does not support the recognition of distinct species in the genus. This result was further corroborated by the presence, although infrequent, of conchologically intermediate forms between some of the Rossmaessleria taxa. Accordingly, Walther et al. (2016) recognized only a single species, R. scherzeri, with 11 subspecies, which are geographically restricted to isolated limestone ranges or outcrops in the western parts of the Rif Mountains in northern Morocco (ten subspecies) and to the Rock of Gibraltar, from where the nominotypical subspecies was described (Zelebor in Pfeiffer & Zelebor 1867).

Download Full-text

Dispersal, home-range size, and habitat use of an endangered land snail, the Oregon forestsnail (Allogona townsendiana)

Canadian Journal of Zoology ◽

10.1139/z2012-056 ◽

2012 ◽

Vol 90 (7) ◽

pp. 875-884 ◽

Cited By ~ 5

Author(s):

A.B. Edworthy ◽

K.M.M. Steensma ◽

H.M. Zandberg ◽

P.L. Lilley

Keyword(s):

British Columbia ◽

Home Range ◽

Habitat Use ◽

Land Snail ◽

Home Range Size ◽

Dispersal Distance ◽

Land Snails ◽

Dispersal Ability ◽

Suitable Habitat ◽

Maximum Displacement

Terrestrial molluscs have declined globally, often as a result of habitat loss and fragmentation. Many land snails are poor dispersers and exist in isolated habitat patches. The Oregon forestsnail ( Allogona townsendiana (I. Lea, 1838)) coincides with the most densely populated region of British Columbia and is listed as endangered in Canada. To investigate the dispersal distances and habitat-use patterns of Oregon forestsnails, we tagged and tracked 21 adult snails at Langley, British Columbia, for up to 3 years (2005–2008). The maximum daily dispersal distance for a snail was 4.5 m and the maximum displacement that we observed for a snail was 32.2 m during 3 years. Snails occupied home-range areas of 18.4–404.4 m2, often overlapping both forest and meadow habitat. Their home-range sizes were smaller in habitats with high availability of stinging nettle ( Urtica dioica L.), which may be an indicator of high-quality habitat. Our results suggest that the Oregon forestsnail is a relatively sedentary species with limited dispersal ability in its adult stage. Although Oregon forestsnails are likely unable to colonize suitable habitat independently, remnant forest–meadow mosaic patches such as our study site provide valuable habitat for Oregon forestsnail, which are supplementary to large tracts of intact forest where most of their populations are found.

Download Full-text

Co-occurring cryptic species pose challenges for conservation: a case study of the African dwarf crocodile (Osteolaemusspp.) in Cameroon

Oryx ◽

10.1017/s0030605314000647 ◽

2014 ◽

Vol 49 (4) ◽

pp. 584-590 ◽

Cited By ~ 3

Author(s):

Nicole L. Smolensky

Keyword(s):

Cryptic Species ◽

Conservation Status ◽

Taxonomic Revision ◽

Single Species ◽

Conservation Strategies ◽

Encounter Rates ◽

Distribution Maps ◽

Species Complexes ◽

Threatened Taxa ◽

Population Structures

AbstractThe conservation status of threatened taxa may be obfuscated by the detection of cryptic species complexes, in both vertebrate and invertebrate species. African dwarf crocodiles (Osteolaemusspp.) are hunted throughout their range but their conservation status is unknown. Few population assessments have been carried out and there has been a taxonomic revision of the number of species in the genus. The similar morphologies ofOsteolaemus tetraspisandOsteolaemus osbornipose a challenge for conservation in Cameroon, where they are still managed as a single species. Nocturnal spotlight surveys were conducted in three regions during August–November 2010 and December 2011–February 2012 to provide population assessments ofO. tetraspisandO. osborniand raise awareness of the two species in Cameroon. The mean encounter rates ofO. tetraspisandO. osborniwere 1.02 ± SD 1.34 (65 individuals in 39 surveys) and 0.61 ± SD 0.38 (three in four surveys) crocodiles per km, respectively. TheO. tetraspispopulation comprised juveniles predominantly and had a male-biased sex ratio. The fewO. osbornidetected comprised both adults and juveniles. Both species are threatened in Cameroon, based on low encounter rates, young population structures and the threats of habitat loss and hunting pressure. This study provides distribution maps and serves as a baseline to quantify population trends and inform conservation strategies.

Download Full-text