[Paleontology • 2026] Wyoteuthis linsterorum • ‘The big chunky belemnite’: A New relict megateuthidid from the Oxfordian (Late Jurassic) of Wyoming, USA, and its place in the evolutionary history of the group

 

Wyoteuthis linsterorum 

Ippolitov, Lippincott, Wahl & Lomax, 2026

 

DOI: doi.org/10.1002/spp2.70123

Abstract

We describe and discuss two finds of large and untypical belemnite rostra originating from the upper part of the Sundance Formation (Oxfordian) of Wyoming, USA. With a diameter reaching c. 60 mm at the anterior end, these rostra are the thickest known for belemnites so far. Herein they are ascribed to a new genus Wyoteuthis, comprising a single new species, W. linsterorum. Both primary and secondary morphological features (rostrum shape, alveolus position, alveolar angle, details of apical grooves and striation) allow us to justify the placement of our new taxon in the family Megateuthididae, which flourished in Toarcian to middle Jurassic time but mostly disappeared during the Bathonian, and is represented by few extremely rare and stratigraphically isolated records from younger strata. In turn, externally similar rostra previously reported in the literature from the same basin belong to Cylindroteuthididae, a common and previously only known family-level group for the Oxfordian of northwestern USA. The new genus represents a relict offshoot of the family Megateuthididae, most likely deriving from the Bajocian members of the genus Brevibelus, formerly described from North America. It demonstrates the presence of a previously unrecognized megateuthidid refugium in the north-eastern Pacific. We also discuss evolutionary macro-trends in belemnites and the possible correlations between rostrum size and soft-body size.

SYSTEMATIC PALAEONTOLOGY

Subclass COLEOIDEA Bather 1888

Order BELEMNITIDA Zittel 1895

Family MEGATEUTHIDIDAE Sachs & Nalnjaeva 1967

‘BREVIBELUS-GROUP’ sensu Ippolitov & Desai 2019

Genus Wyoteuthis nov. 

Type species: Wyoteuthis linsterorum sp. nov.

Derivation of name: A combination of ‘WYO’ (the abbreviation of the State name) and Greek τευθίς (‘squid’); together meaning ‘a squid from Wyoming’.

Differential diagnosis: It differs from Lotharingibelus Weis et al. 2025 by the much larger and more shortened rostrum, and absence of epirostrum; from Brevibelus Doyle 1992 by the same features and clear ventral displacement of the apex; from Arcobelus Sachs in Sachs & Nalnjaeva (1967) by the pronounced ventral, not dorsal displacement of the apex and less compressed cross-section, and smaller alveolar angle (29° in Wyoteuthis vs >35° in Arcobelus); from Pseudosimobelus Dzyuba & C.D. Schraer in Dzyuba et al. (2018) and from Dactyloteuthis Bayle 1878, by the absence of a single ventral groove and extremely short postalveolar part of the rostrum; from the latter additionally with a markedly less compressed rostrum. Other known members of the family Megateuthididae do not have blunt posterior ends comparable with Wyoteuthis.

Occurrence: Upper part of the Sundance Formation (Redwater Shale Member) of Wyoming, USA; late early to early middle Oxfordian (Late Jurassic).

Remarks

Systematic position: Wyoteuthis is a rare taxon with only two specimens known to date. It is stratigraphically isolated from other Megateuthididae, which are mainly restricted to the Toarcian–Bathonian interval. Explanation of its placement in that family and affinity with the genus Brevibelus is provided... 

Wyoteuthis linsterorum gen. et sp. nov., holotype, WYDICE INV-001;
upper lower to lower middle Oxfordian; upper part of Redwater Shale Member, Sundance Formation; 6 km south of Hyattville, Wyoming, USA. Collected by C. Linster.
A, dorsal view. B, right side view. C, alveolar view. D, cross-section 45 mm anterior to the presumed protoconch position. E, apical view. F, frontal CT section, view from ventral side. G, sagittal CT section, right side view. Scale bar represents: 10 mm (A–E; natural size); 30 mm (F, G).

Wyoteuthis linsterorum sp. nov.

 

Derivation of name: After the Linster Family, who discovered the holotype and donated it to the WDC, making it available for science and for the present study.

Diagnosis: Rostrum of large diameter (up to 30–32 mm at protoconch and 65–70 mm anteriorly), conical to subconical with a very short postalveolar part (Pa/DV = 0.37–0.43), posteriorly blunt with ventrally displaced mucronate apex bearing striae, grouped in unclear bunches modified as pit-like depressions. Alveolus extends into most of the length of the rostrum.

Alexey P. Ippolitov, Jessica L. Lippincott, William R. Wahl, Dean R. Lomax. 2026. ‘The big chunky belemnite’: A New relict megateuthidid from the Oxfordian (Late Jurassic) of Wyoming, USA, and its place in the evolutionary history of the group. Papers in Palaeontology. 12(5); e70123. DOI: doi.org/10.1002/spp2.70123 [09 September 2026]

[Mollusca • 2026] Sitala chorchati • A New Species of the Tiny Tree Snail Genus Sitala H. Adams, 1865 (Eupulmonata: Helicarionidae) from Northeastern Thailand

 

Sitala chorchati Tanmuangpak & S. Tumpeesuwan, 

in Tanmuangpak, Nahok, Chanlabut, Taesuk, S. Tumpeesuwan et C. Tumpeesuwan, 2026. 

หอยยอดเจดีย์ช่อฉัตร | DOI: doi.org/10.3390/taxonomy6040061 

 

Abstract

A new species of the tiny tree stylommatophoran snails in the genus Sitala H. Adams, 1865, is described based on specimens recently discovered in dry evergreen and dry dipterocarp forests on limestone hills and in agricultural plantations near limestone hills in Loei Province, northeastern Thailand. The new species is characterized by a high, pyramid-shaped, thin, and translucent yellowish-brown shell with a sharp peripheral keel. Although its external shell morphology resembles that of Sitala liricincta (Stoliczka, 1871), the new species can be distinguished by its greater number of whorls (9¼). Comparative anatomical analysis further revealed significant interspecific differences in genital organs, particularly in the length and shape of the vagina, and in the proportions of the penis, epiphallus, and penial caecum. This discovery is the first verified record of the genus Sitala in Thailand.

Keywords: shell morphology; radula; epiphallic retractor caecum; leaf inhabitant; limestone hill

Taxonomy

Superfamily Helicarionoidea Bourguignat, 1877

Family Helicarionidae Bourguignat, 1877

Subfamily Durgellinae, Godwin-Austen, 1888

Tribe Durgellini Godwin-Austen, 1888

Genus Sitala H. Adams, 1865

Type species. Helix infula Benson, 1848

Diagnosis of genus. Shell turbinoid, thin and translucent, conic or pyramid in shape, outlines, spire conical, consisting of 5.5–7 convex striated whorls. Protoconch and subsequent whorls covered with spiral sculpture, base convex. Umbilicus minute, partially covered. Aperture lack teeth. Peristome thin, simple and not expanded. Penis, vagina, and spermatheca (gametolytic sac) connect to atrium; Penis long, subcylindrical. Epiphallus short, with a simple epiphallic caecum produce into penial retractor. Vas deferens entering epiphallus laterally. Vagina very short (or absent), depending on the position at which the spermatheca enter the genital tract near the atrium. Free oviduct relatively long. Spermathecal stalk enlarges basally; reservoir elongated and embedded in spermoviduct. Amatorial organ (Sarcobellum) present or absent.

 Live snail, Sitala chorchati sp. nov., paratype NHLRU080.

 Photograph: Kitti Tanmuangpak.

 Shell morphology of Sitala chorchati sp. nov., holotype NHLRU079.
(A), Apertural view; (B), Lateral view; (C), Ventral view; (D), Dorsal view.

Photograph: Kitti Tanmuangpak.

Sitala chorchati Tanmuangpak & S. Tumpeesuwan, sp. nov.

Diagnosis. Sitala chorchati sp. nov. is similar in shell morphology to Sitala attegia (Benson, 1859) and Sitala liricincta (Stoliczka, 1871), particularly in having shell conical, high spire shell, thin and translucent. Differing from both species in smaller shell and a greater number of whorls, 4.12–5.28 mm and 9¼ whorls, whereas 5.8 mm and 6½–7 whorls in S. liricincta, and 7–12 mm and 6½–8 whorls in S. attegia (Table 4).

Etymology. The specific epithet “chorchati” is given in honour of Admiral Chorchat Gra-tes of the Royal Thai navy, former Deputy Chief of Defence, an independent conchologist and owner of a private shell collection in Bangkok, Thailand.

 Kitti Tanmuangpak, Benchawan Nahok, Utain Chanlabut, Nonthiwat Taesuk, Sakboworn Tumpeesuwan and Chanidaporn Tumpeesuwan. 2026. A New Species of the Tiny Tree Snail Genus Sitala H. Adams, 1865 (Gastropoda, Eupulmonata, Helicarionidae) from Northeastern Thailand. Taxonomy. 6(4), 61. DOI: doi.org/10.3390/taxonomy6040061 [7 October 2026]

[Mollusca • 2023] Siamochlamys panhai • A New Limestone Karst‐Restricted Terrestrial Snail (Eupulmonata: Helicarionidae) from Thailand

Siamochlamys panhai Pholyotha, 

Pholyotha, Tongkerd et Sutcharit, 2023. 

DOI: doi.org/10.58837/tnh.23.7.258814 

Abstract

A new genus and new species of helicarionid snail, Siamochlamys panhai, is described from limestone outcrops in Thailand. This new genus differs from all helicarionid genera based on morphological characters of shell, radula, and genitalia. The diagnostic characters of Siamochlamys panhai gen. et sp. nov. are depressed shell, well-polished surface, umbilicus opened, and aperture less covered by reflection of columellar margin. The genitalia exhibit a straight epiphallic caecum and small flagellum but lack a dart apparatus; radula has tricuspid central and lateral teeth and bicuspid marginal teeth. The discovery of this karst-associated land snail increases the knowledge of endemic malacofauna in Thailand, and also suggests that many taxa remain undiscovered.

Keywords: endemic, Indochina, land snail, limestones, taxonomy

Superfamily Helicarionoidea Bourguignat, 1877

Family Helicarionidae Bourguignat, 1877

Subfamily Durgellinae Godwin-Austen, 1888

Living snails and mantle extensions of Siamochlamys panhai gen. et sp. nov. paratype CUMZ14211.
A. living snail during relaxed position showing the expansion of mantles B. alcohol-preserved snailshowingshell lobes and dorsal lobes and posterior body C. dorsal view of mantle extensions (shell lobes and dorsal lobes).

Genus Siamochlamys Pholyotha gen. nov.

Etymology.− The name combines ‘Siam’,which is a former name of Thailand,chosen because this snail is restricted to the country as far as we know, and the Greek word ‘chlamys’,meaning “mantle or cloak”. Therefore, the generic name means the land snail with well-developed mantle extensions from Thailand. 

Diagnosis.− Depressed, glossy shellwith open umbilicus, straight epiphallic caecum, short flagellum, no dart apparatus, radula with tricuspidcentral and lateral teeth and bicuspid marginal teeth, andfive mantle extensions well-developed.

Siamochlamys panhai Pholyotha, sp. nov.

Arthit Pholyotha, Piyoros Tongkerd, Chirasak Sutcharit. 2023. Siamochlamys panhai, A New Limestone Karst‐Restricted Terrestrial Snail from Thailand (Eupulmonata: Helicarionidae). Tropical Natural History. Supplement 7;41-50. DOI: doi.org/10.58837/tnh.23.7.258814 

[Mollusca • 2026] Pagodapalaina euphrosyne • A New open-coiled Microsnail Species of the Genus Pagodapalaina (Caenogastropoda: Diplommatinidae) from Thailand

Pagodapalaina euphrosyne Sutcharit,

 

in Sutcharit, Srisonchai, Maneewan, Jeratthitikul et Annate, 2026. 

หอยกระสวยจิ๋วคลายเกลียวยูโฟรซีน  |  DOI: doi.org/10.1556/1777.2026.00169  

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Abstract

A new species of Pagodapalaina from southern Thailand is described. Pagodapalaina euphrosyne Sutcharit, sp. nov. is characterised by a sinistral, elongate-fusiform shell with an open-coiled teleoconch, well-developed radial ribs restricted to the penultimate and last whorls, and the presence of the parietalis and columellaris. Unlike all other congeners, the detached teleoconch subsequently resumes regular coiling, with the last whorl becoming tightly reattached to the preceding whorl. This previously undocumented developmental pattern raises fundamental questions about current understanding of the developmental constraints governing shell coiling in terrestrial caenogastropods.

Keywords: limestone; endemic species; whorl detachment; ecophenotypic plasticity; micro-CT

A, approximate locations of the type locality of all Pagodapalaina species.
Numbers correspond to: 1) P. acme (Laidlaw, 1949) [= Diplommatina laemsonensis Boonmachai, Bergey & Nantarat, 2023]; 2) P. attenuata (Laidlaw, 1949); 3) P. carinaspinosa (Maassen, 2002); 4) P. diminuta (von Möllendorff, 1891); 5) Pagodapalaina euphrosyne sp. nov.; 6) P. gadutensis (Maassen, 2002); 7) P. hidagai (Panha, 1998a); 8) P. hortulanica Chen, 2025; 9) P. jirasaki (Panha, Kanchanasaka & Burch, 2002); 10) P. karoensis (Maassen, 2002); 11) P. krabiensis (Panha & Burch, 1998); 12) P. lenggongensis (Tomlin, 1941) [= Diplommatina lenggongensis nawawii Davison, 1995]; 13) P. parabates (Laidlaw, 1949); 14) P. pongrati (Panha, Kanchanasaka & Burch, 2002); 15) P. prakayangensis (Panha, 1998b); 16) P. sinistra (Tomlin, 1938) [= Diplommatina prakaiphetensis Boonmachai, Bergey & Nantarat, 2023]; 17.1) P. superba superba (Godwin-Austen & Nevill, 1879); 17.2) P. superba brevior (Laidlaw, 1949); 18) P. suratensis (Panha & Burch, 1998);
B, live snail of  Pagodapalaina euphrosyne sp. nov.

Systematics

Superfamily Cyclophoroidea Gray, 1847

Family Diplommatinidae Pfeiffer, 1856

Genus Pagodapalaina Chen, 2025

Pagodapalaina Chen in Chen et al. 2025: 390, 391.

Type species: Diplommatina acme Laidlaw, 1949, by original designation.

Remark: The genus is characterised by a sinistrally coiled, elongate-fusiform shell with tightly to loosely coiled whorls and a shell surface bearing low ridges to prominent and trough-like radial ribs. The internal lamellar system comprises a well-developed columellaris, a parietalis varying from small to well developed, a vertical palatalis that may be absent, and a constriction ranging from weak to strong.

The genus currently comprises 18 recognised species (Chen et al. 2025, MolluscaBase 2026, this study). Of these, three species are known from Sumatra, Indonesia, and nine species, including the new species described herein, are recorded from Thailand. The northern distributional limit of the genus is currently considered not to extend beyond the Isthmus of Kra (Fig. 1A).

Pagodapalaina euphrosyne sp. nov., paratypes CUMZ 14506 from the type locality.
A, B, adult specimens with narrowly expanded lip;
C, juvenile specimen shows an early stage of penultimate whorl, and onset of tall trough-like radial ribs

Pagodapalaina euphrosyne sp. nov. from the type locality.
A, holotype CUMZ 14505, insets show the aperture with columellaris;
B, paratype CUMZ 14506, juvenile with penultimate and last whorl reattached but lip not yet expanded;
C, paratype CUMZ 14506, insets show the protoconch sculpture

Pagodapalaina euphrosyne Sutcharit, sp. nov.

Diagnosis: Shell small, sinistral, elongate-conical, fusiform, with ∼6 whorls. Earlier teleoconch whorls solute for about two whorls, with smooth surface. Penultimate and last whorls regularly coiled, tightly attached, sculptured with very tall, trough-like radial ribs, and fine spiral striations throughout. Peristome double, expanded. Aperture rounded, with four barriers: one parietalis, two vertical palatalis and one columellaris.

Etymology: The specific epithet, euphrosyne, is a noun in apposition derived from Euphrosyne, one of the Three Graces (Charites) in Greek mythology, the personification of joy, beauty, and elegance. It refers to the graceful and delicate shell morphology of the new species.

  Chirasak Sutcharit, Ruttapon Srisonchai, Nattaphong Maneewan, Ekgachai Jeratthitikul and Supunya Annate. 2026. A New open-coiled Microsnail Species of the Genus Pagodapalaina (Caenogastropoda: Diplommatinidae) from Thailand. Animal Taxonomy and Ecology. DOI: doi.org/10.1556/1777.2026.00169 [16 Sep 2026]

𝙋𝙖𝙜𝙤𝙙𝙖𝙥𝙖𝙡𝙖𝙞𝙣𝙖 𝙚𝙪𝙥𝙝𝙧𝙤𝙨𝙮𝙣𝙚 Sutcharit, 2026 หรือ หอยกระสวยจิ๋วคลายเกลียวยูโฟรซีน ค้นพบที่ถ้ำทะลุ อำเภอละงู จังหวัดสตูล โดยตั้งชื่อชนิดตามรูปร่างเปลือกที่ละเอียดอ่อนและสง่างาม เสมือน “ยูโฟรซีน” ผู้เป็น 1ใน 3เทพีแห่งความงามของเทพปกรณัมกรีก 

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[Mollusca • 2025] Pagodapalaina gen. nov. & Pagodapalaina hortulanica • A New sinistral Genus of Diplommatinidae (Gastropoda: Cyclophoroidea) from the Malay Peninsula and Sumatra, with Description of A New Species from Perak, Peninsular Malaysia

Pagodapalaina Z.-Y. Chen gen. nov.
Pagodapalaina hortulanica gen. & sp. nov.
 Pagodapalaina spp. 

in Chen, Sutcharit et Ablett, 2025.

DOI: doi.org/10.11646/zootaxa.5737.3.5  

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Abstract

A new diplommatinid genus, Pagodapalaina Z.-Y. Chen gen. nov., is erected for several sinistral species from the Malay Peninsula and Sumatra originally assigned to Diplommatina Benson, 1849. In addition, a new species of this new genus, Pagodapalaina hortulanica sp. nov., is described from Perak, Peninsular Malaysia. The genus Pagodapalaina gen. nov., is characterised by a sinistral and conical shell with a mostly keeled periphery; the radula consists of a strong central tooth with a large central cusp and smaller lateral cusps; the basal plate of the central tooth bears two small cusps; the lateral and marginal teeth have very short basal parts. An annotated type catalogue of all known species is presented, with illustrations provided for most taxa. Additionally, Diplommatina laemsonensis Boonmachai, Bergey & Nantarat, 2023 and Diplommatina prakaiphetensis Boonmachai, Bergey & Nantarat, 2023 are recognised as synonyms of Pagodapalaina acme (Laidlaw, 1949) comb. nov., and Pagodapalaina sinistra (Tomlin, 1938) comb. nov., respectively.

Mollusca, Micro snails, new genus, new species, Southeast Asia, systematics, taxonomy

Pagodapalaina hortulanica gen. & sp. nov., holotype, NHMUK 19930124.

Pagodapalaina Z.-Y. Chen gen. nov.

Etymology. The name of the new genus is derived from “Pagoda”, referring to the tiered, keeled and tower-like shape of the shell, reminiscent of East Asian pagodas, and diplommatinid genus name Palaina . This genus name is feminine.

Distribution. Thailand, Malaysia, Indonesia. The known species of the new genus are distributed on the Malay Peninsula and Sumatra.

Pagodapalaina hortulanica sp. nov.

Etymology. We adopted Davison’s manuscript name with minor modification. The name hortulanica, meaning “garden-dwelling” in Latin, may refer to the flourishing vegetation of the type locality.

 Pagodapalaina spp. 

FIG. 3. A. Pagodapalaina lenggongensis, syntype, NHMUK 1943.6.28.1. B. Pagodapalaina hidagai, paratype, CUMZ Di 005. C. Pagodapalaina parabates, holotype, NHMUK 1948.11.12.6. D. Pagodapalaina pongrati, paratype, CUMZ Di 044. E. Pagodapalaina prakayangensis, paratype, CUMZ Di 007. F. Pagodapalaina sinistra, syntype, NHMUK 1938.10.25.4. G. Pagodapalaina superba brevior, holotype, NHMUK 1948.11.12.7, the outline of shell follows Laidlaw (1949). H. Pagodapalaina suratensis, paratype CUMZ Di 029. Scale bars = 1 mm.

FIG. 2. A. Pagodapalaina acme, holotype, NHMUK 1948.11.12.5. B. Pagodapalaina attenuate, holotype, NHMUK 1948.11.12.8. C. Pagodapalaina carinaspinosa, paratype, NHMUK 20030224/1. D. Pagodapalaina diminuta, holotype, SMF 105374/1. E. Pagodapalaina gadutensis, paratype, NHMUK 20030225/1. F. Pagodapalaina jirasaki, paratype, CUMZ Di 041. G. Pagodapalaina karoensis, paratype, NHMUK 20030226/1. H. Pagodapalaina krabiensis, paratype CUMZ Di 032. Scale bars = 1 mm.

ZHE-YU CHEN, CHIRASAK SUTCHARIT, JONATHAN D. ABLETT. 2025. Pagodapalaina, A New sinistral Genus of Diplommatinidae from the Malay Peninsula and Sumatra, with Description of A New Species from Perak, Peninsular Malaysia (Gastropoda: Caenogastropoda: Cyclophoroidea). Zootaxa. 5737(3); 389-400. DOI: doi.org/10.11646/zootaxa.5737.3.5 [2025-12-24]

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[Mollusca • 2025] Songkhlanaia songkhramensis • An integrative approach to A Revision of the freshwater mussel Genus Songkhlanaia (Bivalvia: Unionidae), with the Description of A New Species

 Songkhlanaia songkhramensis sp. nov.

Jeratthitikul, Sutcharit & Prasankok, 2025

S. tamodienica, Songkhla Lake Basin, Thailand; 
 S. moreleti, Tonle Sap Basin, Thailand  

DOI: doi.org/10.3897/zookeys.1224.140549  

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Abstract

Mainland Southeast Asia, also known as Indochina, is recognized as a global biodiversity hotspot for freshwater mussels, hosting a significant number of species and exhibiting high levels of endemism. Recently, the monotypic genus Songkhlanaia was described from the Songkhla Lake Basin in southern Thailand. In this study, two additional lineages are revealed, S. moreleti comb. nov. and S. songkhramensis sp. nov., from the Mekong Basin through an integrative taxonomic approach combining morphological characters and molecular phylogenetic analyses. The multi-locus phylogenetic inference supported the monophyly of the genus and further elucidated the sister relationship between S. moreleti and the new species, and with S. tamodienica positioned as a basal lineage. Pairwise uncorrected COI p-distances among these three species also supported the species validity and ranged from 4.2% to 8.24%. Notably, S. songkhramensis sp. nov. and S. moreleti exhibit similarities in shell morphology; however, the new species can be differentiated by more robust pseudocardinal teeth. Both species are distinguishable from S. tamodienica by their approximately twice larger size, more inflated shells, and more prominent, roughened, irregular growth lines on the shell surface. Furthermore, based on the current data, these three species are recognized as endemic and are restricted to disjunct biogeographic areas in Indochina: S. tamodienica in the Songkhla Lake Basin in southern Thailand, S. moreleti in the Tonle Sap and Lower Mekong basins, and S. songkhramensis sp. nov. in the Songkhram Basin and its nearby tributaries of the Middle Mekong Basin.

Key words: Freshwater mussels, Indochina, Mekong Basin, multi-locus phylogeny, new taxa, Pseudodontini, taxonomic revision, Thailand

Family Unionidae Rafinesque, 1820

Subfamily Gonideinae Ortmann, 1916

Tribe Pseudodontini Frierson, 1927

Subtribe Pseudodontina Frierson, 1927

Genus Songkhlanaia Konopleva, Lheknim, Sriwoon, Kondakov, Vikhrev & Bolotov, 2023

Songkhlanaia Konopleva et al., 2023: 13, 14. Bolotov et al. 2023: 12.

Type species: Songkhlanaia tamodienica Konopleva, Lheknim, Sriwoon, Kondakov, Vikhrev & Bolotov in Konopleva et al. 2023 (by original designation).

Species included: Songkhlanaia currently consists of three species: S. tamodienica (type species), S. moreleti comb. nov., and S. songkhramensis sp. nov.

Shells of Songkhlanaia songkhramensis sp. nov. 
A holotype MUMNH-UNI3024 and B paratype MUMNH-UNI3023 from Prahang River, Songkhram Basin, Thailand C specimen MUMNH-UNI0925 from Songkhram River, Songkhram Basin, Thailand.

Pseudocardinal teeth, left valve on the left-hand side, and right valve on the right-hand side
A S. tamodienica, topotype MUMNH-UNI2956 from Tamot Stream, Songkhla Lake Basin, Thailand B S. moreleti, specimen MUMNH-UNI0301 from Phrom Hot Stream, Tonle Sap Basin, Thailand C S. songkhramensis sp. nov., holotype MUMNH-UNI3024 from Prahang River, Songkhram Basin, Thailand. Scale bars: 10 mm.

 Ekgachai Jeratthitikul, Chirasak Sutcharit and Pongpun Prasankok. 2025. An integrative approach to A Revision of the freshwater mussel Genus Songkhlanaia (Bivalvia, Unionidae), with the Description of A New Species. ZooKeys. 1224: 187-209. DOI: doi.org/10.3897/zookeys.1224.140549

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[Mollusca • 2022] Dendronotus shpataki • A New Species of the Genus Dendronotus (Gastropoda: Nudibranchia) from the Sea of Japan: a contribution of citizen science to marine zoology

  

Dendronotus shpataki sp. nov. in natural environment.

Ekimova, Mikhlina, Antokhina & Schepetov, 2022

 

DOI: doi.org/10.31610/zsr/2022.31.1.3 

  Researchgate.net/publication/358210579

Photos by Andrey Shpatak.

Abstract

 The nudibranch genus Dendronotus Alder et Hancock, 1845 is a common component of boreal and arctic ecosystems, which has recently received a considerable attention due to its high cryptic diversity. Here we describe a new species Dendronotus shpataki sp. nov. from the northwestern Sea of Japan, using the material and observations provided by Andrey Shpatak, a local citizen, diver and underwater photographer. We studied morphological features of the new species, including external morphology, coloration, jaw and radular morphology, and configuration of the reproductive system, as well as its ecological traits including possible diet preferences. We obtained DNA sequences and reconstructed the phylogeny by Bayesian Inference and Maximum Likelihood approaches using four molecular markers (mitochondrial COI and 16S rRNA, and nuclear histone H3 and 28S rRNA), and tested the boundaries between the species by calculating the uncorrected p-distances and automatic species delimitation methods ABGD and GMYC. Our results show that D. shpataki sp. nov. differs both morphologically and genetically from all other Dendronotus species. The new species possibly represents a unique example of local endemism, being found in a single locality, while other local Dendronotus species demonstrate wide distribution in the North-West Pacific. We also report on a considerable wearing of the radular teeth during feeding, which is a remarkable case for the Dendronotus.

Key words: North-West Pacific, biodiversity, morphology, radula, molecular markers, phylogeny, Nudibranchia, Dendronotidae, Dendronotus, new species

Dendronotus shpataki sp. nov., general appearance of living specimens.
 Holotype: dorsal view (A), lateral view (B) and ventral view (C).
Paratypes, dorsal view: adult specimens MIMB42309 (D), MIMB42308 (E), MIMB42305 (F)
and juvenile MIMB42306 (G). 

Scale bar: 5 mm.

Dendronotus shpataki sp. nov. in natural environment.
 Paratype MIMB42302 (A–C); the first documented finding of the new species in May 2015,
 the specimen was not collected (D); paratypes MIMB42303 (E, F).

Photos by Andrey Shpatak.

Dendronotus shpataki sp. nov.

I.A. Ekimova, A.L. Mikhlina, T.I. Antokhina and D.M. Schepetov. 2022. A Description of Dendronotus shpataki sp. nov. (Gastropoda: Nudibranchia) from the Sea of Japan: a contribution of citizen science to marine zoology. Zoosystematica Rossica. 31(1); 3–19. DOI: 10.31610/zsr/2022.31.1.3 

  Researchgate.net/publication/358210579_A_description_of_Dendronotus_shpataki_from_the_Sea_of_Japan

[Mollusca • 2026] Fansipanica milae, Vinatachea porcellana, ... • New taxa of Camaenidae (Gastropoda: Stylommatophora) from northern Vietnam

Fansipanica milae Páll-Gergely & Dedov,

   

in Páll-Gergely, Gojšina et Dedov, 2026.

DOI: doi.org/10.3897/zookeys.1280.185160

 

Abstract

The following new taxa are described from northern Vietnam: Fansipanica milae Páll-Gergely & Dedov, gen et sp. nov., Ducanhia Páll-Gergely, gen. nov. (type species: Helix balansai Morlet, 1886), Vinatachea porcellana Páll-Gergely, sp. nov. The reproductive anatomy of all three species is described. Helix (Chloritis) gereti Bavay & Dautzenberg, 1900 is moved to Fansipanica gen nov., and Camaena delsaerdti Thach & F. Huber, 2018 is moved to Vinatachea.

Key words: Anatomy, Fansipan Mountains, new species, systematics, taxonomy

Fansipanica milae gen. et sp. nov. 
A–C. Living specimen, D. Habitat. 

 

Fansipanica milae Páll-Gergely & Dedov, gen et sp. nov., 

Ducanhia Páll-Gergely, gen. nov. 

(type species: Helix balansai Morlet, 1886), 

Vinatachea porcellana Páll-Gergely, sp. nov. 

Barna Páll-Gergely, Vukašin Gojšina and Ivailo Dedov. 2026. New taxa of Camaenidae from northern Vietnam (Gastropoda, Stylommatophora). ZooKeys. 1280: 365-392. DOI: doi.org/10.3897/zookeys.1280.185160 [28 May 2026]

[Mollusca • 2026] Cyllena hermes • From the Dark to the Light: A New Genus and Species of stygobiont hydrobiid (Caenogastropoda: Truncatelloidea: Hydrobiidae) from southern Greece

Cyllena hermes  Radea & Protopapas,

in Radea, Protopapas, Parmakelis et Koskeridou, 2026. 

DOI: doi.org/10.3897/subtbiol.57.189090

Abstract

A new stygobiont hydrobiid genus and species is described from the Stymphalia karst basin (Peloponnese, Greece). Cyllena hermes gen. et sp. nov. is distinguished from other valvatiform or valvatiform–planorboid stygobiont hydrobiids by a unique combination of shell and anatomical characters, supporting the establishment of a new monotypic genus. It is currently known from a single karstic spring connected to the subterranean hydrological network of the Stymphalia polje, indicating a highly localized distribution. Following a precautionary approach, and in accordance with IUCN criteria, the species is here considered to qualify as Vulnerable (VU D2). The discovery of the new genus contributes to the documentation of subterranean aquatic gastropod diversity in Greece and emphasizes the need for further targeted exploration of karst ecosystems in the region.

Keywords: Endemism, Hydrobiidae, IUCN, Peloponnese, karst aquifer

Cyllena hermes gen. et sp. nov.
Shell views of collected specimens. A, G, J, M, P dorsal views B, H, K, N, Q ventral views C–E, I, L, O, R lateral views F operculum A–E holotype.

 Scale bar: 1 mm.

Cyllena hermes gen. et sp. nov.
Views from a single immature specimen. A dorsal view B ventral view C, D lateral view E–G scanning electron micrographs of shell and protoconch respectively.

Scale bars: 1 mm (A–E); 100 μm (F); 50 μm (G).

Systematic description

Class Gastropoda Cuvier, 1795

Subclass Caenogastropoda Cox in Moore, 1960

Order Littorinimorpha Golikov & Starobogatov, 1975

Superfamily Truncatelloidea J.E. Gray, 1840

Family Hydrobiidae W. Stimpson, 1865

Cyllena Radea & Protopapas, 2026, gen. nov. 

Type species. Cyllena hermes sp. nov. by original designation.

Diagnosis. Shell minute, valvatiform to planorboid; umbilicus wide, with earlier whorls visible; soft body unpigmented; eyes absent; bursa copulatrix pyriform; a single seminal receptacle [proximal, rs2 (Radoman 1973)] large and irregular in shape; penis large, dorso-ventrally flattened, distally blunt with papilla and proximally folded, bearing a single, elongate, blunt, medial lobe.

Etymology. The generic name derives from the Greek mythology: Cyllena (Κυλλήνη in Greek) was a nymph of Mt Kyllini, Korinthia, Peloponnese, and the nurturer of the god Hermes. Gender feminine.

Cyllena hermes Radea & Protopapas, 2026, sp. nov.

Etymology. The specific name, used in apposition, is derived from Greek mythology. Hermes (Ἑρμῆς in Greek) was one of the twelve Olympian gods, the messenger of the other Olympian deities, and was born in a cave on Mt Kyllini.

Live specimens of Cyllena hermes gen. et sp. nov.
A–F live mature specimen, shown from the moment of emergence from the shell to active locomotion while foraging 
G–I another mature specimen; White arrows indicate the direction of movement J immature specimen floating at the water surface while feeding
K caddisfly case (Insecta, Trichoptera) constructed from gastropod shells, including shells of Cyllena hermes gen. et sp. nov. Scale bars: 1 mm.

Canella Radea, Dimitrios Protopapas, Aristeidis Parmakelis and Efterpi Koskeridou. 2026. From the Dark to the Light: A New Genus and Species of stygobiont hydrobiid (Caenogastropoda, Truncatelloidea) from southern Greece. Subterranean Biology. 57: 1-21. DOI: doi.org/10.3897/subtbiol.57.189090  [18 Jun 2026]

 

 

[Mollusca • 2026] Georissa meghalayaensis & Acmella bensoni • New Species of Georissa (Gastropoda: Hydrocenidae) and Acmella (Gastropoda: Assimineidae), with new records of Georissa from Northeast India

 

Georissa meghalayaensis sp. nov. and
Acmella bensoni sp. nov. 

 Das & Aravind, 2026

DOI: doi.org/10.5852/ejt.2026.1060.3284 

 x.com/atree_org

Abstract

The present study describes one new species each of Georissa and Acmella from Northeast India. Georissa meghalayaensis sp. nov. and Acmella bensoni sp. nov. are described from Krem Puri, Meghalaya. In addition, Georissa sp. was newly recorded from a soil-leaf litter sample collected at the Sadu Chiru waterfall area in Manipur, and Georissa sarrita was newly recorded from Tuipui in Mizoram. All species were identified based on morphological features, with shell sculpture and suture being the primary distinguishing characters. Notably, all the species from Meghalaya were found inside caves, except for Georissa meghalayaensis (Krem Puri), which was found at the edge of the cave entrance on a wet, moss-covered rocky wall. Further studies are required to confirm the true cavernicolous nature of these microsnails.

Keywords: biodiversity hotspot, cave biodiversity, conchology, conservation, endemics

Georissa meghalayaensis sp. nov. 

Acmella bensoni sp. nov. 

Nipu Kumar Das and Neelavar Ananthram Aravind. 2026. New Species of Georissa (Gastropoda: Hydrocenidae) and Acmella (Gastropoda: Assimineidae), with new records of Georissa from Northeast India.  European Journal of Taxonomy, 1060(1); 1–27. DOI: doi.org/10.5852/ejt.2026.1060.3284 [2026-05-27] 

 x.com/atree_org/status/2065383012116627609

[Mollusca • 2022] Burmochlamys fasciola, B. albida, B. versicolor, ... • Uncovering local Endemism from southeastern Myanmar: Description of the New Karst-associated Terrestrial Snail Genus Burmochlamys (Eupulmonata: Helicarionidae)

 

Burmochlamys Pholyotha & Panha,
A Burmochlamys fasciola sp. nov. paratype showing left and right lateral views;  
D B. albida sp. nov. paratype; E B. moulmeinica sp. nov. paratype;
F B. versicolor sp. nov. paratype; G B. whitteni sp. nov. paratype 

in Pholyotha, Sutcharit, Lin et Panha, 2022.   

 DOI: doi.org/10.3897/zookeys.1110.82461 

Abstract

Salween River basin’s karst ecosystems in southeastern Myanmar remain largely unexplored and are likely to harbour a high terrestrial snail diversity that are often associated with high levels of snail endemism. Here, an outstanding group of new karst-associated terrestrial snails, Burmochlamys gen. nov., are discovered. A study of the comparative morphological and anatomical data reveals that the reproductive tract and radula of this new genus are closely related to the helicarionid genus Sophina Benson, 1859 but shell morphology (shape, size, and sculpture) and mantle extensions are distinct from the latter genus. Burmochlamys gen. nov. now consists of four known nominal species, B. cassidula comb. nov., B. cauisa comb. nov., B. perpaula comb. nov., and B. poongee comb. nov., and five new species; B. albida sp. nov., B. fasciola sp. nov., B. moulmeinica sp. nov., B. versicolor sp. nov., and B. whitteni sp. nov. The highlight is that the members of the new genus show site-specific endemism, being restricted to karstic habitat islands of the Salween River basin. In addition, the discovery supports that the unique and complex structure of Salween River basin’s karst ecosystems are habitats in which the terrestrial malacofauna have speciated and become endemic.

Keywords: Diversity, endemic, Indochina, land snail, limestone, Salween River basin, taxonomy

Family Helicarionidae Bourguignat, 1877

Subfamily Durgellinae Godwin-Austen, 1888

Living snails of Burmochlamys species
A Burmochlamys fasciola sp. nov. paratype CUMZ 14214 showing left and right lateral views B B. cassidula specimen CUMZ 14209
C B. poongee specimen CUMZ 14210 D B. albida sp. nov. paratype CUMZ 14212
E B. moulmeinica sp. nov. paratype CUMZ 14217 F B. versicolor sp. nov. paratype CUMZ 14219 G B. whitteni sp. nov. paratype CUMZ 14222.

Genus Burmochlamys Pholyotha & Panha, gen. nov.

 

Type species: Burmochlamys fasciola sp. nov., by original designation.

Etymology: The name combines Burmo in reference to Burma, the historical name of Myanmar, and the Greek word chlamys meaning mantle or cloak in reference to land snail with well-developed mantle extensions. Therefore, the generic name means the Burmese land snail with the well-developed mantle extensions. The gender of the new generic name is feminine.

Diagnosis: Shell subglobose to globose, small size, little high spire, and sculptured with spiral furrows and undulating radial lines. Snail with five well-developed mantle extensions; caudal horn raised. Genitalia with penial retractor muscle attached at tip of epiphallic caecum; gametolytic organ with rather short to moderate cylindrical duct and bulbous sac; well-developed dart apparatus; flagellum absent. Radula with large monocuspid central tooth and attached by two smaller teeth; laterals and marginals undifferentiated, large monocuspid, and at base of each tooth on outer side attached by a smaller tooth.

B. cassidula comb. nov., B. cauisa comb. nov., 

B. perpaula comb. nov., and B. poongee comb. nov., 

and five new species; B. albida sp. nov., B. fasciola sp. nov., 

B. moulmeinica sp. nov., B. versicolor sp. nov., and B. whitteni sp. nov.

A adult of Burmochlamys moulmeinica sp. nov. while climbing slowly on the karst wall after raining at Lun Nya Pagoda B mating pairs of B. versicolor sp. nov. on the karst wall at Bayin Nyi Cave
C B. versicolor sp. nov. eaten by the carnivorous snail Carinartemis sp. on the karst wall at Bayin Nyi Cave D B. cassidula eaten by the carnivorous snail Haploptychius sp. on the karst wall at Kaw Gon Cave. 

 Arthit Pholyotha, Chirasak Sutcharit, Aung Lin and Somsak Panha. 2022. Uncovering local Endemism from southeastern Myanmar: Description of the New Karst-associated Terrestrial Snail Genus Burmochlamys (Eupulmonata, Helicarionidae).  ZooKeys. 1110: 1-37. DOI: doi.org/10.3897/zookeys.1110.82461