Descriptions are presented of new species of water mites from two mountains in the Malaysian part of Borneo. A new subgenus of the genus Javalbia (Hygrobatidae), i.e. Megapes n. subgen., and 34 new species are described: Limnocharidae: Limnochares (Limnochares) spinosa n. sp.; Oxidae: Oxus (Oxus) fuscus n. sp.; Hydryphantidae: Protzia borneoensis n. sp.; Sperchontidae: Sperchon kinabaluensis n. sp., Sperchonopsis orientalis n. sp.; Hygrobatidae: Hygrobates (Hygrobates) acutipalpis n. sp., H. (Hygrobates) hamatoides n. sp., H. (Hygrobates) striatus n. sp., Atractides (Atractides) neospatiosus n. sp., A. (Atractides) sabahensis n. sp., A. (Atractides) crockerensis n. sp., A. (Atractides) curtisetus n. sp., A.(Tympanomegapus) borneoensis n. sp.; Frontipodopsidae: Frontipodopsis suturalis n. sp.; Aturidae: Javalbia (Javalbia) montana n. sp., J. (Javalbia) solitaria n. sp., J. (Javalbiopsis) borneoensis n. sp., J. (Javalbiopsis) kinabaluensis n. sp., J. (Javalbiopsis) magniseta n. sp., J. (Javalbiopsis) reticulata n. sp., J. (Megapes) uncinata n. sp., Albaxona mahuaensis n. sp., Axonopsis (Axonopsis) longigenitalis n. sp., A. (Axonopsis) rugosa n. sp., A. (Paraxonopsis) truncata n. sp., A. (Brachypodopsis) latipalpis n. sp., A. (Vicinaxonopsis) caeca n. sp., Erebaxonopsis kipungitensis n. sp., Ljania inconspicua n. sp., L. obliterata n. sp., Albia (Albiella) crocker n. sp., Aturus borneoensis n. sp.; Athienemanniidae: Africasia acuticoxalis n. sp.; Arrenuridae: Thoracophoracarus uniacetabulatus n. sp. A key is presented for the Javalbia species of Borneo. New records are given for 10 further species. In the course of revisional work, lectotypes are designated for the following species: Atractides cognatus (K. Viets) and A. propatulus (K. Viets).
The genus Cerithideopsis is most common in mangrove and salt marsh habitats of the New World tropics, but there is also a small radiation in the Indo-West Pacific region. Previously, these Indo-Pacific snails have generally been classified as Cerithidea largillierti (Philippi, 1848). Molecular phylogenetic analysis (partial sequences of mitochondrial COI and 16S rRNA, and nuclear 28S rRNA) of 15 specimens from 8 localities between Japan and Australia reveal three clades, among which there are small morphological differences and which show allopatric distributions. Cerithideopsis largillierti sensu stricto is restricted to Japan and China, while the two other species are described as new: C. australiensis occurs in tropical Australasia and C. malayensis is found from Malaysia to Java and the Philippines. All occur on mud and in pools with leaf litter, in the shaded landward and middle zones of mangrove forests, and do not climb the trees. The species accounts include full synonymies, detailed descriptions of shells based on 82 museum samples, descriptions of living animals, distribution records and maps, and notes on habitat and conservation status.
Gastropod molluscs are one of the most important components of mangrove ecosystem. Mangroves in Central Vietnam have a rather limited distribution due to peculiarities of the coastline morphology and presently their fauna remains understudied. Extensive surveys were conducted in both natural vegetation and artificial mangrove plantations in several localities in Nha Trang Bay from 2005 to 2015. In total 65 species of gastropod molluscs were found alive, 17 of which can be considered as predominantly mangrove-associated. An illustrated guide is provided, with short synonymies and data on ecology and distribution. The recorded molluscan diversity is compared with published data on mangrove gastropods in different regions of the Indo-Pacific. Total species number and the proportion of mangrove-associated species are similar to studied faunas in Hong Kong, Malaysia and Thailand, but the diversity is much lower than that of the mangal fauna of the Philippines.
Angiostrongylus malaysiensis is a potential zoonotic parasite, which reported to co-occur with A. cantonensis in human cerebrospinal fluid. It is a heteroxenous nematode that primarily develops through the early larval stages in gastropods and attains sexual maturity within rats. This study was conducted to determine the host species responsible for the reservoir of A. malaysiensis and investigate the risk factor for transmission among the hosts in Kuala Lumpur, Malaysia. Sampling was conducted in six recreational parks. The rats were trapped alive using steel wire traps with bait, while the gastropods were collected by active searching. The rats were euthanized and dissected to collect any adult worms observed. The molecular detection of A. malaysiensis was performed by PCR on gastropod tissue samples. Biotic and landscape factors were recorded for risk factor analysis. In total, 82 rats and 330 gastropods were collected throughout the study. Overall, 3.64% of gastropods and 32.9% of rats were infected with A. malaysiensis. Rattus tiomanicus (Malayan wood rat) and Parmarion martensi (Yellow-shelled semi-slug) were found as important hosts for A. malaysiensis. Host species, sampling site and macrohabitat type are risk factors associated with the prevalence of A. malaysiensis infection in rats. For gastropods, host species and sampling site are risk factors that correlate with the parasite detection. In total, 128 adult A. malaysiensis were recovered from the infected rats. The mean intensity of infection with adult A. malaysiensis was 4.65 for Rattus rattus complex and 4.90 for R. tiomanicus. Adult worms were found in the pulmonary artery or right ventricle, while eggs and first-stage larvae were found in capillaries of the caudal lung lobe. Infected lungs showed extravasated red blood cells in the alveolar spaces. The pulmonary arteries in the infected lung lobe were thickened. Kepong Metropolitan Park is the hotspot area for A. malaysiensis in Kuala Lumpur. These results provide essential information for public health officials to develop targeted interventions to reduce the transmission of A. malaysiensis in urban areas, particularly in recreational parks.
During fieldwork in Indonesia and Malaysia, eight lots containing 33 specimens belonging to the genus Crenavolva (Ovulidae) were collected. Species were initially identified as Crenavolvaaureola, Crenavolvachiapponii, Crenavolvastriatula and Crenavolvatrailli, respectively. For Crenavolvachiapponii this is the second record. In contrast to the ecological data available from the original description of this species, it was found in shallow water on a gorgonian host coral, i.e. Acanthogorgia sp. A molecular analysis based on COI and 16S mtDNA markers, including sequence data obtained from GenBank, showed that Crenavolvachiapponii should be considered a junior synonym of Crenavolvaaureola and that previously identified ovulid specimens are probably misidentified.
The genus Peronia Fleming, 1822 includes all the onchidiid slugs with dorsal gills. Its taxonomy is revised for the first time based on a large collection of fresh material from the entire Indo-West Pacific, from South Africa to Hawaii. Nine species are supported by mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) sequences as well as comparative anatomy. All types available were examined and the nomenclatural status of each existing name in the genus is addressed. Of 31 Peronia species-group names available, 27 are regarded as invalid (twenty-one synonyms, sixteen of which are new, five nomina dubia, and one homonym), and four as valid: Peronia peronii (Cuvier, 1804), Peronia verruculata (Cuvier, 1830), Peronia platei (Hoffmann, 1928), and Peronia madagascariensis (Labbé, 1934a). Five new species names are created: P. griffithsi Dayrat & Goulding, sp. nov., P. okinawensis Dayrat & Goulding, sp. nov., P. setoensis Dayrat & Goulding, sp. nov., P. sydneyensis Dayrat & Goulding, sp. nov., and P. willani Dayrat & Goulding, sp. nov.Peronia species are cryptic externally but can be distinguished using internal characters, with the exception of P. platei and P. setoensis. The anatomy of most species is described in detail here for the first time. All the secondary literature is commented on and historical specimens from museum collections were also examined to better establish species distributions. The genus Peronia includes two species that are widespread across the Indo-West Pacific (P. verruculata and P. peronii) as well as endemic species: P. okinawensis and P. setoensis are endemic to Japan, and P. willani is endemic to Northern Territory, Australia. Many new geographical records are provided, as well as a key to the species using morphological traits.
As part of an ongoing effort to revise the taxonomy of air-breathing, marine, onchidiid slugs, a new genus, Laspionchis Dayrat & Goulding, gen. nov., is described from the mangroves of South-East Asia. It includes two new species, Laspionchis boucheti Dayrat & Goulding, sp. nov., and Laspionchis bourkei Dayrat & Goulding, sp. nov., both distributed from the Malacca Strait to the Philippines and Australia. This study is based on extensive field work in South-East Asia, comparative anatomy, and both mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) DNA sequences. The two new species are found in the same habitat (mud surface in mangrove forests) and are externally cryptic but are distinct anatomically. Both species are also strongly supported by DNA sequences. Three cryptic, least-inclusive, reciprocally-monophyletic units within Laspionchis bourkei are regarded as subspecies: L. bourkei bourkei Dayrat & Goulding, ssp. nov., L. bourkei lateriensis Dayrat & Goulding, ssp. nov., and L. bourkei matangensis Dayrat & Goulding, ssp. nov. The present contribution shows again that species delineation is greatly enhanced by considering comparative anatomy and nuclear DNA sequences in addition to mitochondrial DNA sequences, and that thorough taxonomic revisions are the best and most efficient path to accurate biodiversity knowledge.
A new genus of onchidiid slugs, Wallaconchis Goulding & Dayrat, gen. n., is described, including ten species. Five species were previously described but known only from the type material: Wallaconchis ater (Lesson, 1830), W. graniferum (Semper, 1880), W. nangkauriense (Plate, 1893), W. buetschlii (Stantschinsky, 1907), and W. gracile (Stantschinsky, 1907), all of which were originally classified in Onchidium Buchannan, 1800. Many new records are provided for these five species, which greatly expand their known geographic distributions. Five species are new: Wallaconchis achleitneri Goulding, sp. n., W. comendadori Goulding & Dayrat, sp. n., W. melanesiensis Goulding & Dayrat, sp. n., W. sinanui Goulding & Dayrat, sp. n., and W. uncinus Goulding & Dayrat, sp. n. Nine of the ten Wallaconchis species are found in the Coral Triangle (eastern Indonesia and the Philippines). Sympatry is high, with up to six species found on the island of Bohol (Philippines) and eight species overlapping in northern Sulawesi (Indonesia). Wallaconchis is distinguished from other onchidiids by its bright dorsal colors (red, yellow, orange) but those are extremely variable and not useful for specific identification. Internally, the reproductive system can be used to identify all Wallaconchis species. The copulatory organs of Wallaconchis species are especially diverse compared to other onchidiid genera, and the possible role of reproductive incompatibility in species diversification is discussed. All specimens examined were freshly collected for the purpose of a worldwide revision of the Onchidiidae Rafinesque, 1815. The species are well delineated using DNA sequences and comparative anatomy. Mitochondrial DNA analysis yields thirteen molecular units separated by a large barcode gap, while nuclear DNA yields nine units. By integrating nuclear DNA and mitochondrial DNA with morphology, ten species are recognized. The natural history of each species (e.g., the microhabitat where they are found) is also documented. Nomenclature is addressed thoroughly (the types of all onchidiid species were examined, lectotypes were designated when needed, nomina dubia are discussed). Morphological characters, transitions to new microhabitats, and diversification processes are discussed in the context of a robust molecular phylogeny.
A new species, Onchidium melakense Dayrat & Goulding, sp. nov., is described, bringing the total to four known species in the genus Onchidium Buchannan, 1800. Onchidium melakense is a rare species with only nine individuals found at three mangrove sites in the Andaman Islands and the Strait of Malacca (western Peninsular Malaysia and eastern Sumatra). The new species is delineated based on mitochondrial (COI and 16S) and nuclear (ITS2 and 28S) DNA sequences as well as comparative anatomy. Each Onchidium species is characterized by a distinct color and can easily be identified in the field, even in the Strait of Malacca where there are three sympatric Onchidium species. An identification key is provided. In addition, Onchidium stuxbergi (Westerlund, 1883) is recorded for the first time from eastern Sumatra, and Onchidium pallidipes Tapparone-Canefri, 1889, of which the type material is described and illustrated here, is regarded as a new junior synonym of O. stuxbergi.
The Bornean representatives of the genus Georissa (Hydrocenidae) have small, dextral, conical, calcareous shells consisting of ca. three teleoconch whorls. Our recent study on the Georissa of Malaysian Borneo has revealed high intra- and inter-specific variation in the "scaly" group (a group of species with striking scale-like surface sculpture). The present study on the "non-scaly" Georissa is the continuation of the species revision for the genus. The "non-scaly" species are also diverse in shell sculptures. This informal group comprises Georissa with subtle spiral and/or radial sculpture. The combination of detailed conchological assessment and molecular analyses provides clear distinctions for each of the species. Conchological, molecular, and biogeographic details are presented for 16 species of "non-scaly" Georissa. Three of these are new to science, namely Georissacorrugatasp. n., Georissainsulaesp. n., and Georissatrusmadisp. n.
The genera Aulacospira and Pseudostreptaxis of the Philippines are revised based on the collections of the Senckenberg Forschungsinstitut und Naturmuseum (Frankfurt am Main, Germany), the Florida Museum of Natural History (USA), and recently collected material. Three new species are described: Aulacospiralens Páll-Gergely & Auffenberg, sp. n., Aulacospirakrobyloides Páll-Gergely & Schilthuizen, sp. n., Pseudostreptaxisharli Páll-Gergely & Schilthuizen, sp. n.
Sabah, a Malaysian state at the north-eastern tip of Borneo, is situated in one of the Earth's biodiversity hotspots yet its freshwater gastropod diversity remains poorly known. An annotated checklist of the freshwater gastropods is presented, based on specimens deposited in the BORNEENSIS collection of the Institute for Tropical Biology and Conservation at Universiti Malaysia Sabah, Malaysia. A KMZ file is also provided, which acts as a repository of digital images and complete collection data of all examined material, so that it can be shared and adapted to facilitate future research.
A total of 11 species and 1 subspecies of Alycaeus were recognised in Peninsular Malaysia prior to this study. However, these taxonomic descriptions of Alycaeus taxa were based on limited numbers of examined materials, where a whole spectrum of morphological variations were not accounted for and diagnoses were often provided without sufficient comparison between congeners from across the peninsula. We reviewed Peninsular Malaysian Alycaeus through the examination of 5137 specimens in 522 collection lots from all major museum collections and literature sources. Based on these examined materials, we utilised a more comprehensive revised set of 39 shell and operculum characters, as well as living animal colour to describe all Alycaeus species in this paper. We also noted their habitat and ecology, as well as updated the distribution of each species. Of the 12 previously described taxa, 10 are reconfirmed as present on Peninsular Malaysia (Alycaeus balingensis, Alycaeus carinata, Alycaeus conformis, Alycaeus gibbosulus, Alycaeus kapayanensis, Alycaeus kelantanensis, Alycaeus liratulus, Alycaeus perakensis perakensis, Alycaeus perakensis altispirus and Alycaeus thieroti) and 2 are confirmed as absent from the peninsula (Alycaeus jagori and Alycaeus pyramidalis). A new record of Alycaeus robeleni is reported for Peninsular Malaysia. One species, Chamalycaeus jousseaumei is confirmed as present on the peninsula and is reassigned to Alycaeus. The subspecies Alycaeus perakensis altispirus Möllendorff, 1902, is elevated to species. Examined Peninsular Malaysian materials that do not fit previously recognised species are described as new species. A total of 11 new species are proposed (Alycaeus selangoriensissp. n., Alycaeus costacrassasp. n., Alycaeus ikanensissp. n., Alycaeus alticolasp. n., Alycaeus charasensissp. n., Alycaeus kurauensissp. n., Alycaeus regalissp. n., Alycaeus virgogravidasp. n., Alycaeus senyumensissp. n., Alycaeus expansussp. n., Alycaeus clementsisp. n.). Overall, 23 species of Alycaeus are now recognised in Peninsular Malaysia.
Pencemaran air di Tasik Chini, Pahang kian meruncing akibat pembangunan sekitar yang tidak terkawal menyebabkan kemusnahan rantaian makanan sekaligus mengancam kelangsungan hidup komuniti asli. Justeru, kajian telah dijalankan bagi mengenal pasti faktor, impak dan keberkesanan strategi dengan menggunapakai Teori Pengambilalihan. Selain itu, kajian ini dipilih untuk memenuhi kelompangan kajian terdahulu yang lebih menekankan kepentingan pengekalan biodiversiti flora dan fauna berbanding kajian terhadap kehidupan komuniti setempat. Maka, kajian deskritif tinjauan telah digunakan melalui kaedah pemerhatian, temu bual mendalam bersama empat orang informan, dianalisis secara transkripsi, triangulasi dan analisis kandungan. Dapatan kajian menunjukkan faktor pencemaran air berpunca daripada pembinaan empangan air, projek pembangunan, aktiviti pembalakan, aktiviti perlombongan dan hakisan tanih. Sementara, pertanian komersial juga menjejaskan kegunaan domestik, hidupan akuatik terganggu, perubahan sifat air, kehilangan sumber pendapatan, dan tahap kesihatan terjejas. Oleh itu, cadangan memperluaskan program advokasi seperti pengawalan pembuangan sampah sarap, pematuhan Penilaian Impak Alam Sekitar (EIA), penglibatan pihak awam dan swasta, pemantauan kesihatan, kesedaran awam, dan melakukan penyelidikan lanjutan. Kajian mendapati dua buah syarikat China mengeksport bijih besi yang diperoleh sekitar Tasik Chini menggunakan permit AP (Eksport dan Import) dari negeri lain, bukannya Pahang. Meskipun syarikat tersebut tidak mempunyai lesen melombong tetapi mereka mempunyai segala kelengkapan alatan memproses dan menjalankan operasinya hingga kini. Diharapkan isu pencemaran air di Tasik Chini dapat dipulihkan demi menjamin kelestarian sejagat.
THE DIVERSITIES OF MANGROVE TREES AND OF THEIR ASSOCIATED GASTROPODS WERE ASSESSED FOR TWO MANGROVE REGIONS ON THE WEST COAST OF PENINSULAR MALAYSIA: Langkawi Island and Sungai Merbok. The mangrove area sampled on Langkawi Island was recently logged and replanted, whereas the area sampled in Sungai Merbok was part of a protected nature reserve. Mangrove and gastropod diversity were assessed in four 50 m(2) (10 × 5 m) sites per region. The species richness (S), Shannon Index (H') and Evenness Index (J') were calculated for each site, and the mean S, H' and J' values were calculated for each region. We report low tree and gastropod S, H' and J' values in all sites from both regions. For Langkawi Island, the mean S, H' and J' values for mangrove trees were S = 2.00±0, H' = 0.44±0.17 and J' = 0.44±0.17; the mean S, H' and J' values for gastropods were S = 4.00±1.63, H' = 0.96±0.41 and J' = 0.49±0.06. In Sungai Merbok, the mean S, H' and J' values for mangrove trees were S = 1.33±0.58, H' = 0.22±0.39 and J' = 0.22 ±0.39; the mean S, H' and J' values for gastropods were S = 4.75±2.22, H' = 1.23±0.63 and J' = 0.55±0.12. This study emphasises the need for baseline biodiversity measures to be established in mangrove ecosystems to track the impacts of anthropogenic disturbances and to inform management and restoration efforts.
This study provides the first marine gastropod checklist from the Sarawak Exclusive Economic Zone (EEZ). Gastropod samples were collected from selected stations in the Sarawak EEZ using an otter trawl net with a stretched mesh size of 38 mm at the cod end. The trawling operations were conducted more than 12 nautical miles from the coast, and the area was divided into three depth strata: I) 20-50 m, II) 50-100 m and III) 100-200 m. A total of 23 gastropod species were identified during the two-month sampling period from 16 August until 6 October 2015, representing 8 superfamilies, 15 families and 20 genera. Superfamily Tonnoidea was represented by 7 species, followed by Muricoidea (5 species), Cypraeoidea (4 species), and Buccinoidea and Conoidea (both with 2 species). Other superfamilies were represented by a single species. Only 3 species were obtained in 2 depth strata, namely Melo melo, Murex aduncospinosus and Tonna galea. In addition, 9, 13 and 4 species of gastropods were found in strata I, II and III, respectively. The information on gastropod distributions at different depth strata in the Sarawak EEZ could be useful in updating the Malaysian species diversity database.
Land reclamation in Penang began two decades ago and is still rampant with
large reclamation projects planned to be executed in the near future. The present study
provides the first information on effects of land reclamation in Penang towards the coastal
macroinvertebrates. This study assessed the abundance, diversity, and evenness of
coastal invertebrates assumed to be the foremost affected when land is reclaimed. Three
kinds of areas were focused on: reclaimed, unclaimed (adjacent to reclaimed), and
undisturbed. A total of 53 species of macroinvertebrates from 10 classes (Gastropoda,
Bivalvia, Polychaeta, Malacostraca, Maxillopoda, Echinoidea, Polyplacophora,
Branchiopoda, Scaphopoda, and Holothuroidea) were sampled. Reclaimed areas were
moderately rich in species averaging 11 species compared to 7 species in adjacent and
14 in undisturbed areas. Species richness was the highest in Teluk Aling (an undisturbed
area) with 22 species, and was the lowest in Gurney Drive (an adjacent area) with 2
species. The average species diversity and evenness on reclaimed land was the lowest
with values of 1.9974 and 0.5787, respectively. The diversity was higher by 5.07% in
adjacent areas and by 22.92% in undisturbed areas compared to reclaimed areas.
Species evenness was 29.75% higher in unreclaimed areas and 17.87% higher in
undisturbed areas compared to reclaimed areas. Land reclamation reduces species
diversity and evenness, and to a lesser extent, species richness.
Benthic faunal communities are important components in the intertidal zones.
The diversity and abundance of the benthic communities are subjected to different natural
and anthropogenic disturbances. The study was conducted as one off sampling on 6th
November 2013 (1) to investigate the abundance and distribution of soft sediment
communities in relation to environmental variables and (2) investigate the changes of
population structure and diversity using spatial scales of 1 m, 10 m, and 100 m. Results
indicated a total of 110 individuals of macrobenthos consisting of 7 different groups
(Annelida, Bivalvia, Crustacea, Gastropoda, Nematoda, Nemertea, Polychaeta) and 4
different groups of meiobenthos (Copepoda, Nematoda, Ostracoda, Polychaeta)
consisting 920 individuals were recorded. Dissolved oxygen played the most significant
role in affecting the distribution of soft sediment communities while ammonia
concentrations only affected marcobenthic organisms. However, sediment grain size did
not show significant correlation (p>0.05) on soft sediment communities. Hence,
understanding how different properties of benthos respond to changes in environmental
variables is crucial in determining how the impacts on the sediment are tolerated by the
benthic organisms.
Identifying potential food sources in mangrove ecosystems is complex because of the multifarious inputs from both land and sea. This study, which was conducted in the Manko mangrove ecosystem of Okinawa, Japan, determined the composition of the stable isotopes δ(13)C and δ(15)N in primary producers and macrozoobenthos to estimate the potential food sources assimilated and to elucidate the target trophic levels of the macrozoobenthos. We measured the two stable isotope signatures of three gastropods (Cerithidea sp., Cassidula mustelina, Peronia verruculata), two crabs (Grapsidae sp., Uca sp.), mangrove tree (Kandelia candel) leaves, and sediment from the mangrove ecosystem. The respective carbon and nitrogen isotope signature results were as follows: -22.4‰ and 8.6‰ for Cerithidea sp., -25.06‰ and 8‰ for C. mustelina, -22.58‰ and 8‰ for P. verruculata, -24.3‰ and 10.6‰ for unidentified Grapsidae, -21.87 ‰ and 11.5 ‰ for Uca sp., -29.81‰ and 11‰ for K. candel, and -24.23‰ and 7.2‰ for the sediment. The stable isotope assimilation signatures of the macrozoobenthos indicated sediment as their food source. Considering the trophic levels, the stable isotope values may also indicate that the five macrozoobenthos species were secondary or higher consumers.
Pachychilidae is one of the freshwater gastropod family which was previously known under the Potamididae and Thiaridae families. Studies on freshwater gastropods especially on conchcology examinantions are still inadequate compared to marine gastropods. Morphological and morphometric studies of gastropods are practically used to identify and differentiate between species and necessary to complement molecular studies due to its low cost and tolerable resolving power of discrimination. The aim of the current study is to provide information on morphological and morphometric characteristics of Pachychilidae in Bintulu, Sarawak stream. A total of 20 individuals from each species of Sulcospira testudinaria, Sulcospira schmidti, Brotia siamensis, and Tylomelania sp. from Pachychilidae familiy were collected at three different sites from a small stream within the Bintulu area. Fourteen measurement of shell morphometrics were converted into proportioned ratios and analysed for univariate and multivariate analysis. Three shell morphometric (Aperture width, AW; Whorl width, WW2; and, Interior anterior length, AINL) of Pachychilidae indicated significant differences (P < 0.05) between species. However, multivariate analysis revealed that these shell morphometrics are pre-eminent factors to discriminate genus Sulcospira, Brotia and Tylomelania, as well as between Sulcospira species. This current study also suggests that these three characteristics are unique to Sulcospira species due to strong distinction among species. Findings on these three characteristics are significant for Sulcospira spp. as this study is the first shell morphometric report on the Pachychilidae species in Sarawak.