Ancient lakes as hotspots of diversity: A morphological review of an endemic species flock of Tylomelania (Gastropoda: Cerithioidea: Pachychilidae) in the Malili lake system on Sulawesi, Indonesia

Hydrobiologia (Impact Factor: 2.28). 11/2007; 592(1):11-94. DOI: 10.1007/s10750-007-0765-8


The viviparous freshwater gastropod Tylomelania (Caenogastropoda: Cerithioidea: Pachychilidae) endemic to the Indonesian island Sulawesi has radiated extensively in two
ancient lake systems. We here present the first systematic species-level review of taxa in the five lakes of the Malili lake
system, which contains the most diverse and best studied freshwater fauna on Sulawesi. Our results indicate a significantly
higher diversity of Tylomelania in these lakes than previously perceived based on morphological evidence for delimiting the taxa. We describe nine new species,
thus increasing the number of taxa known from the Malili lakes to 25. Tylomelania species are inhabiting all available substrates in the lakes, and the diversity of habitats is reflected in an unparalleled
range of radula types in this closely related group. Several species show a high intraspecific variability in some characters,
and their closer investigation will probably lead to the discovery of more cryptic species. As it is, this species flock on
Sulawesi is among the largest freshwater mollusc radiations known. Since the Malili lake system also contains other large
endemic species flocks of e.g. crustaceans and fishes, it is a major hotspot of freshwater biodiversity in Asia to become
a conservation priority.

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    • "Samples from 191 sites comprising 1,170 individuals of 62 species including 26 undescribed morphospecies (species delimitations are based on shell and radula characters that have been shown to be effective in distinguishing sympatric species in Tylomelania from the lakes of Sulawesi [41]) were collected across the entire distribution range of Tylomelania on Sulawesi (Figure 1, Table S1). Permits for conducting fieldwork were issued by LIPI (1999–2007) and RISTEK (from 2008) as the responsible authorities in Indonesia. "
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    ABSTRACT: The complex geological history of the Indonesian island Sulawesi has shaped the origin and subsequent diversification of its taxa. For the endemic freshwater snail Tylomelania a vicariant origin from the Australian margin has been hypothesized. Divergence time estimates from a mtDNA phylogeny based on a comprehensive island-wide sampling of Tylomelania fit regional tectonic constraints and support the 'out-of-Australia' vicariance hypothesis. The Banggai-Sula region of the Sula Spur, the Australian promontory colliding with West Sulawesi during the Miocene, is identified as a possible source area for the colonization of Sulawesi by the ancestor of Tylomelania. The molecular phylogeny also shows a rapid diversification of Tylomelania into eight major lineages with very little overlap in their distribution on the island. Haplotype networks provide further evidence for a strong spatial structure of genetic diversity in Tylomelania. Distribution boundaries of the major lineages do at best partially coincide with previously identified contact zones for other endemic species groups on Sulawesi. This pattern has likely been influenced by the poor dispersal capabilities and altitudinal distribution limits of this strict freshwater inhabitant. We suggest that late Miocene and Pliocene orogeny in large parts of Sulawesi has been the vicariant event driving primary diversification in Tylomelania.
    PLoS ONE 06/2014; 9(6):e98917. DOI:10.1371/journal.pone.0098917 · 3.23 Impact Factor
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    • "Based on the revised list of Skadar Lake gastropods and endemics (see Table 2) and the mean surface area (472 km2) we get the index of gastropod endemism of 0.478. With this relatively high value, Skadar Lake exceeds such famous lakes as Malawi and Titicaca (see: Rintelen et al. 2007 and, Dejoux and Iltis 1992, respectively). "
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    ABSTRACT: AbstractKarucia sublacustrina a new species of freshwater snails (Hydrobiidae, Gastropoda) is described based on material collected from Skadar Lake (Montenegro, Albania). The new species belongs to monotypic genus Karucia gen. n. The shell morphology and body shape of the new genus resembles Radomaniola Szarowska, 2006 and Grossuana Radoman, 1973, from which it differs in the larger shells with relatively slim and a slightly, but clearly shouldered body whorl. The number of gastropods from Skadar Lake basin tallies now 50 species. The adjusted rate of gastropod endemicity for Skadar Lake basin is estimated to be 38%. By compiling faunal and taxonomic data we also aim to provide information of relevance as to conservation efforts.
    ZooKeys 03/2013; 281(281):69-90. DOI:10.3897/zookeys.281.4409 · 0.93 Impact Factor
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    • "Ancient Lakes have been identified as hotspots of freshwater biodiversity mainly due to the parallel occurrence of in situ speciation and radiation in various groups of organisms (Cristescu et al. 2010). Most of these lakes are also noted for their exceptionally diverse and highly endemic faunas of freshwater molluscs (Boss 1978; von Rintelen et al. 2007; Albrecht and Wilke 2008; Glaubrecht 2008; Albrecht et al. 2009). The Yunnan-Guizhou Plateau in southwest China comprises about 60 tectonic lakes with a complex geological history, which are known to harbour a unique fauna of gastropod species, particularly of viviparids (Tchang and Tsi 1949; Zhang et al. 1981; Zhang et al. 1997; Du et al. 2011). "
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    ABSTRACT: A new aberrant species of the planorbid genus Gyraulus, Gyraulus luguhuensis n. sp., is described from Lake Lugu (Lugu-hu, in Chinese), Southwest China. The generic assignment with Gyraulus is based on features of the genital anatomy that are characteristic for members of that genus, in particular the presence of a chitinized penial stylet. Gyraulus luguhuensis n. sp. differs from most other congeners by its large, thick shell with an elevated spire. Similarly, aberrant shells are known from congeners in other Ancient Lakes worldwide indicating a potentially convergent evolution of shell characteristics in exclusively lacustrine species. Gyraulus luguhuensis differs from other lacustrine Gyraulus species with similarly large shells in having a sub-terminal penis pore and an unkeeled shell.
    Molluscan Research 02/2013; 33(1). DOI:10.1080/13235818.2012.754146 · 0.51 Impact Factor
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