[Diplopoda • 2026] Rhopalomeris dulcia, R. lentiginosa, R. verhoeffi, ... • Five New Species of the Pill Millipede Genus Rhopalomeris Verhoeff, 1906 (Glomerida: Glomeridae) from Thailand

Rhopalomeris dulcia, 
R. verhoeffi  

Sapparojpattana & Likhitrakarn,

in Sapparojpattana, Jeratthitikul, Siriwut, Srisonchai, Wesener, Sutcharit et Likhitrakarn, 2026.  

DOI: doi.org/10.1163/18759866-bja10090 

 facebook.com/ASRUChula 

Abstract

An integrative approach based on morphological characteristics and DNA data from the mitochondrial COI gene has revealed five new species of the pill millipede genus Rhopalomeris Verhoeff, 1906 from Thailand: Rhopalomeris muka Sapparojpattana & Likhitrakarn, sp. nov., R. lentiginosa Sapparojpattana & Likhitrakarn, sp. nov., R. dulcia Sapparojpattana & Likhitrakarn, sp. nov., R. punctata Sapparojpattana & Likhitrakarn, sp. nov., and R. verhoeffi Sapparojpattana & Likhitrakarn, sp. nov. The five new species are distinguishable from their congeners by distinctive color patterns and telopod structure. The interspecific genetic divergences between the new species and other Rhopalomeris species ranged from 7.86 to 13.71%. Intraspecific genetic divergences within these five species ranged from 0 to 4.53%, with the highest divergences found in R. carnifex and R. verhoeffi sp. nov. This is consistent with both the wide distribution range and the significant intraspecific morphological variations observed in these latter two species. Furthermore, the taxonomic scope of R. carnifex in Thailand is reviewed, and intraspecific morphological variations within R. carnifex and R. verhoeffi sp. nov. are discussed. A distribution map, morphological illustrations from SEM, and an updated key to all known Rhopalomeris species are also provided.

Keywords: DNA barcoding; Indochina; integrative taxonomy; phylogeny; systematics

Rhopalomeris dulcia sp. nov., (A, B) paratype (MUMNH-GLO188), habitus, live coloration (C–E) ♀ paratype (MUMNH-GLO188), alcohol preserved, in dorsal, ventral, and lateral views (A) unrolled in sublateral view (B) rolled in sublateral view.

(A, B) image not to scale (C–E) scale bars: 2 mm

Rhopalomeris verhoeffi sp. nov., (A, B) paratype (MUMNH-GLO201), habitus, live coloration of color morph 2 (C–E) ♀ paratype (MUMNH-GLO201), alcohol preserved specimen of color morph 2 in dorsal, ventral, and lateral views (A) unrolled in sublateral view (B) rolled in sublateral view.

(A, B) image not to scale (C–E) scale bars: 2 mm

 Rhopalomeris muka Sapparojpattana & Likhitrakarn, sp. nov.

R. lentiginosa Sapparojpattana & Likhitrakarn, sp. nov. 

 R. dulcia Sapparojpattana & Likhitrakarn, sp. nov. 

 R. punctata Sapparojpattana & Likhitrakarn, sp. nov. 

 R. verhoeffi Sapparojpattana & Likhitrakarn, sp. nov. 

Distributions of currently known Rhopalomeris species in Thailand and Myanmar

(A) Bayesian inference tree focusing on the detailed topology of Rhopalomeris carnifex (Pocock, 1889) and R. verhoeffi sp. nov., with colored drawings illustrating the color variations within each species. All millipede drawings are not to scale.
(B, C) Maps of southern Thailand showing the distributions of color morphs for (B) R. carnifex and (C) R. verhoeffi sp. nov. The different shaded colors in each pie chart represent the proportion of the corresponding color morphs in that locality.

 Pichsinee Sapparojpattana, Ekgachai Jeratthitikul, Warut Siriwut, Ruttapon Srisonchai, Thomas Wesener, Chirasak Sutcharit, and Natdanai Likhitrakarn. 2026. Five New Species of the Pill Millipede Genus Rhopalomeris Verhoeff, 1906 (Diplopoda, Glomerida) from Thailand. Contributions to Zoology. 95(1); 52–102. DOI: doi.org/10.1163/18759866-bja10090 [20 Feb 2026]

 facebook.com/ASRUChula/posts/1351095590368500

***งานวิจัยใหม่: กิ้งกือกระสุนลูกกวาด 5 ชนิดใหม่ของโลกจากประเทศไทย
และการมีรูปแบบสีที่หลากหลายซึ่งพบในบางชนิด***

...

รายชื่อชนิดใหม่ดังนี้

.

1. 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨 𝙢𝙪𝙠𝙖 Sapparojpattana & Likhitrakarn, 2026
กิ้งกือกระสุนลูกกวาดมหิดลกาญจน์
 ค้นพบที่ มหาวิทยาลัยมหิดล วิทยาเขตกาญจนบุรี อำเภอไทรโยค จังหวัดกาญจนบุรี

2. 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨 𝙡𝙚𝙣𝙩𝙞𝙜𝙞𝙣𝙤𝙨𝙖 Sapparojpattana & Likhitrakarn, 2026
ค้นพบที่ ตำบลท่าขนุน อำเภอทองผาภูมิ จังหวัดกาญจนบุรี

3. 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨 𝙙𝙪𝙡𝙘𝙞𝙖 Sapparojpattana & Likhitrakarn, 2026
ค้นพบที่ ตำบลบ้านนา อำเภอเมืองชุมพร จังหวัดชุมพร

4. 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨 𝙥𝙪𝙣𝙘𝙩𝙖𝙩𝙖 Sapparojpattana & Likhitrakarn, 2026
ค้นพบที่ ตำบลไร่เก่า อำเภอสามร้อยยอด จังหวัดประจวบคีรีขันธ์

5. 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨 𝙫𝙚𝙧𝙝𝙤𝙚𝙛𝙛𝙞 Sapparojpattana & Likhitrakarn, 2026
ตั้งชื่อเป็นเกียรติแก่ Karl Wilhelm Verhoeff ผู้ตั้งสกุลกื้งกือกระสุนลูกกวาด 𝙍𝙝𝙤𝙥𝙖𝙡𝙤𝙢𝙚𝙧𝙞𝙨
ค้นพบครั้งแรกที่ น้ำตกกะทู้ อำเภอกะทู้ จังหวัดภูเก็ต และกระจายตัวหลายพื้นที่ในภาคใต้ของประเทศไทย 

[Crustacea • 2023] Polkamenes gen. nov. & Tympanicheles gen. nov. • Polka-dotted Treasures: Revising A Clade of Ascidian- and Bivalve-associated Shrimps (Caridea: Palaemonidae)

 

Polkamenes pycnodontae (Bruce, 1978),

  Tympanicheles ornatus (Holthuis, 1952),

 B) Anchistus australis, 

D) A. demani,  

F, H) A. miersi,

in de Gier et Fransen. 2023.  

DOI: doi.org/10.1163/18759866-bja10042 

 Researchgate.net/publication/370486457

photographs by C.H.J.M Fransen

Abstract

Most marine shrimp species of the family Palaemonidae are characterized by symbiotic associations with hosts that belong to a wide range of invertebrate phyla. One clade of related endosymbiotic species has evolved to live inside the branchial chambers of ascidians and the mantle cavities of bivalve molluscs. The phylogeny of this clade (comprising 15 bivalve-associated species in the genera Anchistus, Neoanchistus, and Paranchistus, and three species of ascidian-associated species in the genus Dasella) is the topic of the present study, which is based on both morphological and molecular data. A concatenated phylogeny reconstruction was built by using the markers coi and 16S. With the help of a total evidence approach (with a scored morphological datamatrix), species could be added for which no molecular data were available. An ancestral character state analysis was performed to detect host switches. In contrast to another endosymbiotic clade, the ancestral host state was found to be slightly in favour of bivalves. The phylogenetic relevance of morphological features is discussed with a focus on a tympanal organ located in the major chelipeds of some bivalve-associated shrimp species. This little-known anatomical structure is illustrated by sem and µCT scans. Its possible function is discussed. In the phylogeny reconstructions, both Anchistus and Paranchistus were found to be polyphyletic. They were reclassified to obtain a more natural classification: Anchistus custoides and Anchistus custos were transferred to the resurrected genus Ensiger. Paranchistus liui, P. nobilii, P. pycnodontae, and P. spondylis were transferred to Polkamenes gen. nov. Anchistus pectinis and P. ornatus were transferred to Tympanicheles gen. nov. Per genus, a key to the species is provided.

 

Keywords: commensal shrimp, host switching, symbiosis, taxonomic revision, total evidence

A) Anchistus australis Bruce, 1977, RMNH.CRUS.D.58048, stn ber.28, in Tridacna squamosa Lamarck, 1819; B) A. australis, RMNH.CRUS.D.53540, stn ter.12, in T. squamosa;
C) Anchistus demani Kemp, 1922, RMNH.CRUS.D.42792, stn sey.792, in Tridacna maxima (Röding, 1798); D) A. demani, RMNH.CRUS.D.58049, stn thu.07, in T. maxima;
E) Anchistus gravieri Kemp, 1922, RMNH.CRUS.D.58052, stn FR15, in Hippopus hippopus (L., 1758);
F) Anchistus miersi (De Man, 1888), RMNH.CRUS.D.42970, stn sey.720, in T. squamosa: G) A. miersi, RMNH.CRUS.D.46473, sw Sulawesi, in T. squamosa; H) A. miersi, RMNH.CRUS.D.53568, stn ter.19, in T. squamosa. 

photographs by C.H.J.M Fransen

Polkamenes pycnodontae (Bruce, 1978) RMNH.CRUS.D.48261, from Hyotissa hyotis (L., 1758)

 Genus Polkamenes gen. nov.

Etymology. ‘Polkamenes’: named after the characteristic blue-, red-, and orange-dotted pattern seen on the species’ carapace, abdomen, and appendages ‘Polka dots’ (English, in combination with the common palaemonid suffix ‘-menes’; see e.g., Ancylomenes Okuno & Bruce, 2010, Laomenes Clark, 1919, Periclimenes). Gender: masculine.

recognize four species: Polkamenes liui (Li, Bruce & Manning, 2004); Polkamenes nobilii (Holthuis, 1952); Polkamenes pycnodontae (Bruce, 1978); and Polkamenes spondylis (Suzuki, 1971).

Distribution. Shiraiso, Manazura-Machi, Kanagawa Prefecture, Japan, (cf. Suzuki, 1971, Hayashi, 2005, 2006); South China Sea (Li et al., 2004).

  Tympanicheles ornatus (Holthuis, 1952), RMNH.CRUS.D.42794, from Atrina vexillum (Born, 1778) 

Genus Tympanicheles gen. nov.

Etymology. ‘Tympanicheles’: named after the ‘drum-like’ veil on the species’ major chela. Built from ‘Tympani-’, a suffix for drum in Latin (‘Tympanum’), and ‘-cheles’ for claws in Latin. Gender: masculine.

 

  recognize two species: Tympanicheles ornatus (Holthuis, 1952), and Tympanicheles pectinis (Kemp, 1925).

 

 Werner de Gier and Charles H.J.M. Fransen. 2023. Polka-dotted Treasures: Revising A Clade of Ascidian- and Bivalve-associated Shrimps (Caridea: Palaemonidae). Contributions to Zoology. 92(3); 179-282. DOI: doi.org/10.1163/18759866-bja10042

  Researchgate.net/publication/370486457_Revising_a_clade_of_ascidian-_and_bivalve-associated_shrimps_Palaemonidae

 twitter.com/Werner_deGier/status/1653740009235570690

[Cnidaria • 2024] Umimayanthus mirnangga, U. jebarra, U. raksasa, etc. • Museum Collections as Untapped Sources of Undescribed Diversity of Sponge-zoantharian Associations with the Description of Six New Species of Umimayanthus (Zoantharia: Parazoanthidae) from Western Australia and eastern Indonesia

 

Umimayanthus cf. aruensis (Pax, 1911) 

in Montenegro, Fromont, Richards, Kise, Gomez, Hoeksema et Reimer, 2024. 

DOI: 10.1163/18759866-bja10069 

 x.com/deepseaUWA 

  Researchgate.net/publication/383565499

 

Abstract

The zoantharian genus Umimayanthus consists largely of species that live in obligate symbioses with sponges. Although zoantharians have often been overlooked in field collecting campaigns and in research, sponges are usually well-collected, and many natural history museums harbor numerous sponge specimens. Thus, these sponge collections may also include previously overlooked zoantharian species. Such is the case in this research, in which we examined sponge specimens in museum collections from Western Australia and eastern Indonesia. Based on our morphological and molecular analyses, we herein describe six species of Umimayanthus new to science, and redescribe another species described over a century ago. These species can be distinguished by their sponge associations, gross polyp and colony morphology, and depth ranges. Based on these findings, it appears that the Central Indo-Pacific region of Western Australia and Indonesia can be considered a hotspot for sponge-associated zoantharian diversity. We provide a key for the identification of all formally described species in the genus, but caution that there are likely more Umimayanthus species awaiting discovery.

Keywords: Anthozoa; biodiversity; coral reefs; Porifera; species descriptions

Phylum Cnidaria Hatschek, 1888 

Subphylum Anthozoa Ehrenberg, 1831 

Class Hexacorallia Haeckel, 1896 

Order Zoantharia Rafinesque, 1815 

Family Parazoanthidae Delage & Hérouard, 1901 

Genus Umimayanthus Montenegro, Sinniger and Reimer 2015

Umimayanthus cf. aruensis (Pax, 1911) 

Umimayanthus mirnangga sp. nov. WAM Z88824 (holotype)

Umimayanthus mirnangga sp. nov. Montenegro, Kise & Reimer

Etymology. The specific epithet “mirnangga” is derived from the phoneme used to refer to a young single woman in the Wunambal language. This in reference to the fact that the colonies of U. mirnangga sp. nov. are exclusively composed of solitary polyps. “mɨrnangga binya” n., B-class young woman. Syn: munangga. See Bengmoro et al. (1971) and Boona (2022).

Umimayanthus jebarra sp. nov. Montenegro, Kise & Reimer

Etymology. The specific epithet “jebarra” is derived from the phoneme used to refer to the emu in Wunambal language. This in reference to the elongated shape of the polyps in U. jebarra sp. nov., which resemble the neck of an emu. As well, the name can act as a memorial to all the emus killed during the Great Emu Wars of 1932 in Western Australia. “jebarra anya” n., A-class. emu. Dromaius novaehollandiae. Syn: garnanganyja; jeebarra. See Mangglamarra (1991) and Karadada et al. (2011).

Umimayanthus wunanggu sp. nov. 

Umimayanthus wunanggu sp. nov. Montenegro, Kise & Reimer

Etymology. The specific epithet “wunanggu” is derived from the phoneme used to refer to the hill white gum tree in Wunambal language. This in reference to U. wunanggu sp. nov. forming colonies of white polyps connected by a thin coenenchyma that extends on a linear branching pattern over the sponge surface. “wunanggu winya” n., W-class. /wunaŋgu/. hill white gum, tropical red box, Eucalyptus brachyandra von Mueller, 1859. See Capell (1941) and Karadada (2011).

Umimayanthus discolor sp. nov. Montenegro, Kise & Reimer

Etymology. The specific epithet “discolor” means multiple colors in Latin. This is in reference to U. discolor sp. nov. forming colonies of polyps with contrasting colorations between the oral disk and the column, stolon, and coenenchyma.

Umimayanthus lynherensis sp. nov. Montenegro, Kise & Reimer  

 Etymology. The specific epithet “lynherensis” is derived from the locality where the type specimen was collected, the Lynher Bank sea country north Kimberley, Western Australia, Australia.  

Umimayanthus raksasa sp. nov. Montenegro, Kise & Reimer

Etymology. The specific epithet “raksasa”, which means “giant” or “gigantic” in Indonesian, refers to the large size of the polyps of this species in comparison to the other members of its genus.

 

 Javier Montenegro, Jane Fromont, Zoe Richards, Hiroki Kise, Oliver Gomez, Bert W. Hoeksema and James Davis Reimer. 2024. Museum Collections as Untapped Sources of Undescribed Diversity of Sponge-zoantharian Associations with the Description of Six New Species of Umimayanthus (Zoantharia: Parazoanthidae) from Western Australia and eastern Indonesia.  Contributions to Zoology. DOI: doi.org/10.1163/18759866-bja10069

  x.com/deepseauwa/status/1830439654870667504

Researchgate.net/publication/383565499_six_new_species_of_Umimayanthus_from_Western_Australia

[Entomology • 2021] Ptomaphagus thebeatles • A previously unrecognized Beetle (Coleoptera: Leiodidae) from Europe, with Remarks on Urban Taxonomy and Recent Range Expansion

Ptomaphagus (Ptomaphagus) thebeatles Schilthuizen, Latella & Njunjić,

in Schilthuizen, van Oostenbrugge, Visser, Van der Meer, Delval, Dias, Köster, Maarschall, Peeters, Venema, Zaremba, Beltrami, Rossato, Latella, Nieuwenhuis, de Rop, Njunjić, Perreau & Koene, 2021.

DOI: 10.1163/18759866-BJA10007 

 Researchgate.net/publication/341909199

Abstract

Anthropogenic environmental change is leading to changes in distribution for many organisms. While this is frequently discussed for prominent organisms of high conservation value, the same is true for the many cryptic species that rarely figure in debates on the human impact. One such cryptic taxon is the European Ptomaphagus sericatus (Chaudoir, 1845) and related forms. During a citizen science expedition in the Vondelpark, Amsterdam, the Netherlands, we obtained two forms of this species complex. We placed the examination of these specimens in the context of a re-analysis of the species group, and, using DNA barcoding and genital study on material collected thoughout Europe, found that the P. sericatus species complex consists of three distinct, partly sympatric species, one of which was previously undescribed. On the basis of collection data, at least two species, P. medius and P. thebeatles sp. n., show signs of having recently undergone (possibly anthropogenic) range changes, with P. medius even reaching North America. We describe P. thebeatles sp. n.; we raise two subspecies, viz. P. sericatus sericatus (Chaudoir, 1854) and P. sericatus medius (Rey, 1889) to the level of species, and designate a neotype for the former; we identify P. dacicus Jeannel, 1934 and P. pyrenaeus Jeannel, 1934 as junior synonyms of P. sericatus, and P. compressitarsus (Rey, 1889) as a junior synonym of P. subvillosus Goeze, 1777; we identify P. septentrionalis Jeannel, 1934 and P. miser (Rey, 1889) as junior synonyms of P. medius; we designate lectotypes for P. medius and P. miser.

Keywords: citizen science; distribution; Europe; identification; Ptomaphagini; taxonomy

Ptomaphagus (Ptomaphagus) thebeatles Schilthuizen, Latella & Njunjić, 2020, sp. n.

Nomenclature: Ptomaphagus sericatus (Chaudoir, 1845) (Schilthuizen 1989: 61)

Ptomaphagus sericatus (Chaudoir, 1845) (Schilthuizen 2010: 2-3)

Etymology: Named for the band The Beatles, which no beetle has yet been named after. The name also commemorates the ‘Bed In for Peace’ by John Lennon and Yoko Ono in the nearby Hilton Hotel, exactly 50 years (to the day) prior to the collection date of the holotype.

Distribution: This species has a wide distribution across southern and western Europe (fig. 5). It reaches southern Russia in the east and Spain in the west. In recent decades, it appears to have shifted or extended its distribution northward: whereas specimens from northern France date back to the late 19th century, all material from The Netherlands dates only from the past 35 years.

 Menno Schilthuizen, Wesley van Oostenbrugge, Stefan Visser, Marrit van der Meer, Richard Delval, Claudia Dias, Heko Köster, Rudie Maarschall, Norbert Peeters, Peter Venema, Ryan Zaremba, Cristina Beltrami, Marzia Rossato, Leonardo Latella, Florinda Nieuwenhuis, Nicole de Rop, Iva Njunjić, Michel Perreau, and Joris M. Koene. 2021. Ptomaphagus thebeatles n. sp., A previously unrecognized Beetle from Europe, with Remarks on Urban Taxonomy and Recent Range Expansion (Coleoptera: Leiodidae). Contributions to Zoology. 90(1); 1-20. DOI:  10.1163/18759866-BJA10007  

Researchgate.net/publication/341909199_Ptomaphagus_thebeatles_a_previously_unrecognized_beetle_from_Europe

[Mollusca • 2021] Angustopila coprologos & A. psammion • The World’s Tiniest Land Snails (Gastropoda, Pulmonata, Hypselostomatidae) from Laos and Vietnam

Angustopila coprologos Páll-Gergely, Jochum & Hunyadi; 

 Angustopila psammion Páll-Gergely, Vermeulen & Anker;

Angustopila pallgergelyi, Acmella nana, Notharinia micro 

in Páll-Gergely, Jochum, Vermeulen, Anker, Hunyadi, et al., 2022.

DOI: 10.1163/18759866-bja10025 

 facebook.com/PallGergelyBarna

Abstract

Two new, extremely small land snail species, Angustopila coprologos Páll-Gergely, Jochum & Hunyadi n. sp. and Angustopila psammion Páll-Gergely, Vermeulen & Anker n. sp. are described from northern Vietnam and northern Laos, respectively. The former is characterized by a rough surface sculpture and bears tiny mud granules arranged in a pattern of radial lines on its shell surface. The latter species is the new global record-holder of the tiniest land snail title, with a shell width of 0.6–0.68 mm and a shell height of 0.46–0.57 mm. These measurements surpass the former records of Angustopila pallgergelyi and Acmella nana.

Keywords: Acmella; Angustopila; Arinia; miniaturization; shell; ornamentation

Systematic descriptions

Family Hypselostomatidae Zilch, 1959

Genus Angustopila Jochum, Slapnik & Páll-Gergely, 2014

Angustopila Jochum, Slapnik & Páll-Gergely, 2014; Jochum et al., 2014: 410: 26.

Type species: Systenostoma tamlod Panha & Burch, 1999, by original designation.

Angustopila coprologos Páll-Gergely, Jochum & Hunyadi n. sp.

 

Diagnosis: A strongly depressed-globular Angustopila species with a wide umbilicus, strong spiral sculpture consisting of a series of coarse elevations (flat-topped beads) in a chain-like pattern and four well-developed teeth (1 parietal, 2 palatal, 1 basal).

Differential diagnosis: Angustopila coprologos n. sp. can be easily distinguished from all other Angustopila species by its depressed shell, the four apertural denticles and the pronounced sculpture.

Etymology: The specific epithet coprologos (Ancient Greek for dung gatherer) refers to the mud granules (here assumed to be faeces) placed on this species’ shell. Used as a noun in apposition.

Distribution: This species is known only from the type locality in Bolikhamsay Province, Laos: ca. 13 km southeast (in a straight line) from the town Lak Sao (see also supplementary figs S1–S2).

Angustopila psammion Páll-Gergely, Anker & Vermeulen, n. sp.

 

Diagnosis: An Angustopila species with a depressed-globular shell with dome-shaped spire, thick spiral striae, kidney-shaped aperture with single parietal denticle not reaching parietal callus.

Differential diagnosis: Angustopila pallgergelyi Dumrongrojwattana, Chuenit & Wongkamhaeng, 2021 is similar in shell and aperture shape, but is larger, has a prominent palatal tooth (absent in Angustopila psammion n. sp.) and a stronger parietal tooth. Angustopila coprologos n. sp. is slightly larger, has a rough shell surface, and has an additional subcolumellar tooth and two palatal teeth.

Etymology: The specific epithet (ψαμμίον) means a grain of sand in Greek and is used as a noun in apposition.

Distribution: This new species is known only from the type locality, Cap La Cave, Ha Long Bay, Quang Ninh Province, Vietnam.

Size comparisons of the former record holders,
Angustopila pallgergelyi, Acmella nana, Notharinia micro, the smallest marine snail, Ammonicera minortalis, and the two new species [Angustopila coprologos n. sp. and Angustopila psammion n. sp.] described herein.
 The image of Ammonicera minortalis Rolán, 1992 is from Oliver et al. (2012), whereas the other images (Acmella nana and Arinia micro) are from their respective original descriptions. The figure of Acmella nana is adjusted to scale with the measurement of the smallest specimen, whereas for Angustopila coprologos n. sp. and Angustopila psammion n. sp., the holotypes (not the tiniest shells) are shown.

Conclusions: 

Two species, Angustopila psammion Páll-Gergely, Vermeulen & Anker n. sp. and Angustopila coprologos Páll-Gergely, Jochum & Hunyadi n. sp. are described from northern Laos and northern Vietnam, respectively. With its shell width of 0.60–0.68 mm and shell height of 0.46–0.57 mm, Angustopila psammion n. sp. is the new global record-holder of the title of the tiniest land snail, surpassing the former two record-holders, Angustopila pallgergelyi and Acmella nana. The calculated volume for the smallest adult snail (including the shell) is 0.036 mm3. In the absence of extreme food specialization, miniaturization of land snails is probably driven by the accessibility of small spaces in the subsoil, although other scenarios, such as avoidance of larger predators, cannot be ruled out. The lower limit of adult shell size may be determined by the fact that it must accommodate at least one viable egg, the size of which in turn, may be limited by the minimum number of neurons to be functional in the hatchling. On the other hand, Angustopila coprologos n. sp. is characterized by a rough surface sculpture (most complex among all known and undescribed species of its genus), and minuscule mud granules arranged in radial lines on its shell surface. These granules may play a role in camouflage and mate recognition or function like mini sponges for water retention.

 

 Barna Páll-Gergely, Adrienne Jochum, Jaap J. Vermeulen, Katja Anker, András Hunyadi, Aydin Örstan, Ábel Szabó, László Dányi and Menno Schilthuizen. 2022. The World’s Tiniest Land Snails from Laos and Vietnam (Gastropoda, Pulmonata, Hypselostomatidae). Contributions to Zoology. DOI: 10.1163/18759866-bja10025 

 brill.com/view/journals/ctoz/aop/article-10.1163-18759866-bja10025/article-10.1163-18759866-bja10025.xml

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