Nonmarine Mollusks from Archaeological Sites on Mo‘orea, Society Islands, French Polynesia, with Descriptions of Four New Species of Recently Extinct Land Snails (Gastropoda: Pulmonata: Endodontidae)

Abstract

Nonmarine mollusks recovered during archaeological excavations on the island of Mo'orea, Society Islands, French Polynesia, were analyzed as part of a multidisciplinary study of anthropogenic environmental change. Records of now-extinct taxa in dated archaeological contexts were combined with historic collection data from the 1830s to the present to determine the chronology of extinction of the 10 species of land snails of the family Endodontidae that formerly inhabited the island. One species known only from a stratum antedating human settlement on the island and three known only archaeologically but from imprecisely dated strata were certainly extinct by the late nineteenth century but may have disappeared earlier. One species collected in 1838 was extinct by the late nineteenth century, and all of the described endodontid species present in the mid-to late nineteenth century are undoubtedly now extinct because none was collected by the 1934 Mangarevan Expedition or by subsequent collectors. Only a single unidentified living endodontid has been observed on Mo'orea since the nineteenth century. Additional extinctions or extirpations have occurred among the Helicarionidae, terrestrial Assimineidae, and probably also in the Helicinidae. Four new species of Endodontidae are described: Libera kondoi, Minidonta opunohua, Nesodiscus nummus, and N. cookei. Libera jacquinoti, described in 1850 from poorly localized material and until now not collected subsequently, is shown to have inhabited Mo'orea.

Molecular phylogenetics and premating isolation in the punctoid land snails of Belau (Republic of Palau, Oceania)

“…In this same locality, we also collected a putative new species of genus Sinployea Solem, 1983, a genus previously unknown from Belau, and which represents the first new extant punctoid genus record in almost 50 years. While subfossil species of punctoids have been recovered across the Pacific since the group was last revised by Solem (Abdou & Bouchet, 2000; Christensen, 1982; Christensen et al., 2018; Sartori et al., 2013; Zimmermann et al., 2009), no new genus records have been reported from living individuals. Unfortunately, we found only three specimens of this putative new species at this locality, one of which was juvenile.…”

The Sixth Mass Extinction: fact, fiction or speculation?

“…5 ), and species new to science, although already extinct, have been described (e.g. Christensen, 1982 ; Abdou & Bouchet, 2000 ; Bouchet & Abdou, 2001 ; Zimmermann, Gargominy & Fontaine, 2009 ; Richling & Bouchet, 2013 ; Sartori, Gargominy & Fontaine, 2013 , 2014 ; Gerlach, 2016 ; Christensen, Kahn & Kirch, 2018 ) (Fig. 4 ).…”

Restructuring of nutrient flows in island ecosystems following human colonization evidenced by isotopic analysis of commensal rats

“…This leads to distinct δ 13 C values in primary producers which are then passed reliably up the consumer chain (21). Nitrogen isotopes provide insight into the trophic level of an organism, as a stepwise 15 N-enrichment between trophic levels causes consumers to have δ 15 N values approximately 3-5‰ higher than their food (22)(23)(24). Marine food webs tend to be larger and more complex, leading to generally higher δ 15 N values than their terrestrial counterparts, although some shellfish and reef fish can overlap with δ 15 N values of terrestrial animals.…”

“…Intensive agricultural and animal husbandry regimes centered around these translocated species, which included the use of fire in forest clearance and slash-and-burn agriculture, resulting in significant transformations to Pacific biomes (14). A combination of human predation, the introduction of new faunal predators and competitors, and habitat alteration led to the extirpation or extinction of a large component of the native Pacific island biota, including endemic forest, land birds and seabirds, and terrestrial gastropods and arthropods (15,16). The nearly ubiquitous transport of the commensal Pacific rat (Rattus exulans) into virtually every island ecosystem in the Pacific likewise contributed to extinctions of local avifauna and reduction in native plant diversity (16,17).…”