Adrienne Jochum

Recent fossil shell mining for a new rail line in the Orlando area of Orange County, Florida
has uncovered two species of the ellobioid genus Carychium O. F. Müller, 1773 in a bed
of freshwater marl from the Lower Pleistocene Nashua Formation. To taxonomically
interpret these finds, the well-preserved shells were imaged via high-resolution X-ray
tomography (micro-CT) to view significant internal diagnostic characters such as the
columellar configuration and the degree of lamellar sinuosity and their relationship in
context to the entire shell. The image data are compared to that of type material and
extant and fossil Carychium species inhabiting the SE USA, Mexico, Central America,
and Jamaica. Based on these results, the species Carychium floridanum G. H. Clapp,
1918 and Carychium nashuaense sp. nov. are identified from fossil shells dating from
the Early Pleistocene. This work documents the first fossil members of C. floridanum
and the first fossil Carychium from the SE USA.

Abstract When seldom life history events serendipitously get documented by exceptional preservation in the fossil record, a unique telescopic opportunity arises for interpreting fossils within their paleoenvironment as well as for understanding ancestral relationships of current life forms. We present a rare glimpse of live birth by a terrestrial mother snail, incidentally, engulfed by amber as she released her young in a tropical forest during the mid-Cretaceous (early Cenomanian). The exceptional finding featuring the preservation of a snail’s 99-million-year-old soft-body together with five neonate shells represents the earliest known fossilized incidence of viviparity in a terrestrial snail. Based on high-resolution photographs and µCT scans, we describe the mother snail as a new species of cyclophoroid, Cretatortulosa gignens sp. nov. Our finding provides remarkable perspectives for interpreting gastropod evolution 80 million years earlier than the fossil record has known up to now. It shows that viviparity was already a relevant reproductive strategy in the Cretaceous, probably increasing the offspring’s survival chance in a predator-lurking tropical forest.

Malkowsky, Y. and Jochum, A. 2014. Three-dimensional reconstructions of pallial eyes in Pectinidae (Mollusca: Bivalvia). — Acta Zoologica (Stockholm) 00: 000–000. Recent methodological and technical developments in comparative morphology have broadened understanding of evolutionary traits in molluscs. Scientists are capable of reconstructing organ systems and entire architectural physiologies with utmost precision. The pallial eyes of Pectinidae are amongst the most complex visual systems found in molluscs and have aroused scientific curiosity for decades. This investigation presents the most comprehensive description of pallial eye morphology in four major groups of Pectinidae: Aequipectini group, Pectininae, Chlamydinae and Palliolinae. The cornea, lens, retinae and branching of the optic nerve are depicted in topographic detail. Three-dimensional reconstructions of microtome sections enable the comparison of whole eyes and structures in contrast to single-section analysis. Here, we demonstrate two significant findings: (i) the morphology of corneae and lenses varies in scallop species and (ii) the retinae are innervated in different ways in different species. Moreover, we show how morphological characteristics such as the hyperbolic shape of the lens can be overlooked if only single sections are investigated.

Exposure to pollutants under multiple environmental stressors (e.g., climate change and global warming) and the genetic diversity of populations are suspected to have serious impacts on populations and ecosystems but have only rarely been analysed. In the present study, we investigated the effects of the biocide tributyltin (TBT) within a temperature gradient (17, 20 and 23 degrees C) on life history parameters of a genetically diverse (GEN+) and a highly inbred population (GEN-) of the midge Chironomus riparius. While endpoints, mortality and reproduction parameters were considered, the population growth rate as an integrative endpoint was determined. We found severe effects for GEN-, indicating that populations with lower genetic diversity are more endangered by combined stressors such as increasing temperature and chemical pollution compared to genetically diverse populations.

Burmese amber continues to provide unique insights into the terrestrial biota inhabiting tropical equatorial forests during mid-Cretaceous time. In contrast to the large amount and great diversity of terrestrial species retrieved so far, aquatic biota constitute rare inclusions. Here we describe the first freshwater snail ever preserved in amber. The new speciesGalba primasp. nov. belongs in the family Lymnaeidae, today a diverse and near globally distributed family. Its inclusion in terrestrial amber is probably a result of the amphibious lifestyle typical of modern representatives of the genus. The finding of a freshwater snail on the Burma Terrane, back then an island situated at some 1500 km from mainland Asia, has implications for the dispersal mechanisms of Mesozoic lymnaeids. The Cenomanian species precedes the evolution of waterfowl, which are today considered a main vector for long-distance dispersal. In their absence, we discuss several hypotheses to explain the disjunct occurrence of the new species.

ABSTRACT Corrigendum to the paper, ‘A new species of land snail from the genus Diplommatina Benson, 1849 (Gastropoda, Caenogastropoda, Diplommatinidae) from Sikkim Himalaya, North East India’ published in Molluscan Research 41, 1–7, 2021 DOI: 10.1080/13235818.2021.1970352.

Computed tomographic (CT) imaging allows new accessibility to shells of gastropod fossil taxa and their extant relatives, providing new data for interpreting former systematic assignments. The highly questionable ellobiid assignment of the nonmarine gastropod genus Protocarychium Pan, 1982 from the Lower Jurassic of Hunan, China, is reevaluated using CT imaging to assess internal aspects of the shell. By comparing these new data to those of stylommatophoran, ellobiid, and caenogastropod clades in the literature, this work reveals that Protocarychium bears no affinity to the Carychiidae, which are otherwise known only from the Cenozoic, but rather to the Paleozoic land snail family Anthracopupidae Wenz, 1938. This finding constitutes the first Asian appearance of anthracopupid snails beyond their known North American and European range. Contrary to the current opinion, we suggest the Anthracopupidae to be a basal stylommatophoran clade, which places the origin of Stylommatophora at least in the late Carboniferous.

The Southeast Asian genus Angustopila, currently comprising 13 nominal species, encompasses the world’s tiniest land snails. This work shows that there are far more species than previously suspected, and that this genus is in fact, a very speciose group of tiny snails widely distributed in Southeast Asia. Angustopila is revised based on type material of known species as well as 211 samples newly collected in China, Laos, Myanmar, Thailand and Vietnam. Altogether, 53 species and one subspecies are recognised, of which 42 species and subspecies are new to science: A. akrodon Páll-Gergely & Hunyadi, sp. nov., A. apiaria Páll-Gergely & Hunyadi, sp. nov., A. apiostoma Páll-Gergely & Vermeulen, sp. nov., A. apokritodon Páll-Gergely & Hunyadi, sp. nov., A. antidomedon Páll-Gergely & Hunyadi, sp. nov., A. babel Páll-Gergely & Vermeulen, sp. nov., A. bathyodon Páll-Gergely & Hunyadi, sp. nov., A. bidentata Páll-Gergely & Jochum, sp. nov., A. cavicola Páll-Gergely & Dumrongrojwattana, sp. nov., A. cicatricosa Páll-Gergely & Vermeulen, sp. nov., A. coprologos uninodus Páll-Gergely & Grego, ssp. nov., A. erawanica Páll-Gergely & Dumrongrojwattana, sp. nov., A. fratermajor Páll-Gergely & Vermeulen, sp. nov., A. fraterminor Páll-Gergely & Vermeulen, sp. nov., A. gracilis Páll-Gergely & Hunyadi, sp. nov., A. halongensis Páll-Gergely & Vermeulen, sp. nov., A. hyron Páll-Gergely & Vermeulen, sp. nov., A. maasseni Páll-Gergely & Vermeulen, sp. nov., A. majuscula Páll-Gergely & Hunyadi, sp. nov., A. margaritarion Páll-Gergely & Hunyadi, sp. nov., A. megastoma Páll-Gergely & Vermeulen, sp. nov., A. occidentalis Páll-Gergely & Hunyadi, sp. nov., A. oostoma Páll-Gergely & Vermeulen, sp. nov., A. papaver Páll-Gergely & Hunyadi, sp. nov., A. parallela Páll-Gergely & Hunyadi, sp. nov., A. prolixa Páll-Gergely & Hunyadi, sp. nov., A. pusilla Páll-Gergely & Hunyadi, sp. nov., A. pustulata Páll-Gergely & Hunyadi, sp. nov., A. quadridens Páll-Gergely & Vermeulen, sp. nov., A. rara Páll-Gergely & Hunyadi, sp. nov., A. reticulata Páll-Gergely & Hunyadi, sp. nov., A. somsaki Páll-Gergely & Hunyadi, sp. nov., A. steffeki Páll-Gergely & Grego, sp. nov., A. tetradon Páll-Gergely & Hunyadi, sp. nov., A. thersites Páll-Gergely & Vermeulen, sp. nov., A. tonkinospiroides Páll-Gergely & Vermeulen, sp. nov., A. tridentata Páll-Gergely & Hunyadi, sp. nov., A. tweediei Páll-Gergely & Hunyadi, sp. nov., A. uvula Páll-Gergely & Hunyadi, sp. nov., A. vandevenderi Páll-Gergely & Jochum, sp. nov., A. vitrina Páll-Gergely & Hunyadi, sp. nov., A. vomer Páll-Gergely & Hunyadi, sp. nov., A. werneri Páll-Gergely & Hunyadi, sp. nov.
Angustopila subelevata Páll-Gergely & Hunyadi, 2015 is moved to the synonymy of Angustopila elevata (F. G. Thompson & Upatham, 1997), and A. singuladentis Inkhavilay & Panha, 2016 is a junior synonym of A. fabella Páll-Gergely & Hunyadi, 2015. Three species, namely A. elevata, A. fabella and A. szekeresi, are widespread over several hundred kilometres while some other species (A. huoyani, A. parallela sp. nov., A. cavicola sp. nov.) are known from just two sites a few hundred kilometres apart. All others are small range or single-site endemics. The reproductive anatomy of A. erawanica sp. nov. is described.

The Southeast Asian genus Angustopila, currently comprising 13 nominal species, encompasses the world’s tiniest land snails. This work shows that there are far more species than previously suspected, and that this genus is in fact, a very speciose group of tiny snails widely distributed in Southeast Asia. Angustopila is revised based on type material of known species as well as 211 samples newly collected in China, Laos, Myanmar, Thailand and Vietnam. Altogether, 53 species and one subspecies are recognised, of which 42 species and subspecies are new to science: A. akrodon Páll-Gergely & Hunyadi, sp. nov., A. apiaria Páll-Gergely & Hunyadi, sp. nov., A. apiostoma Páll-Gergely & Vermeulen, sp. nov., A. apokritodon Páll-Gergely & Hunyadi, sp. nov., A. antidomedon Páll-Gergely & Hunyadi, sp. nov., A. babel Páll-Gergely & Vermeulen, sp. nov., A. bathyodon Páll-Gergely & Hunyadi, sp. nov., A. bidentata Páll-Gergely & Jochum, sp. nov., A. cavicola Páll-Gergely & Dumrongrojwattana, sp. nov...