Laevistrombus Abbott 1960 (Gastropoda: Strombidae): Indian and Southwest Pacific Species
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See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/331112386 Laevistrombus Abbott 1960 (Gastropoda: Strombidae): Indian and southwest Pacific species Article in Zootaxa · February 2019 DOI: 10.11646/zootaxa.4555.4.2 CITATIONS READS 4 1,141 4 authors: Stephen J Maxwell Aart Marinus Dekkers James Cook University Independent researcher; CPA at Dekkers Accountants 39 PUBLICATIONS 53 CITATIONS 58 PUBLICATIONS 63 CITATIONS SEE PROFILE SEE PROFILE Tasmin Rymer Bradley C. Congdon James Cook University James Cook University Brisbane 59 PUBLICATIONS 338 CITATIONS 103 PUBLICATIONS 2,384 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Seabirds of the GBR View project Dugong dugon feeding in tropical Australian seagrass meadows: implications for conservation planning View project All content following this page was uploaded by Stephen J Maxwell on 20 October 2019. The user has requested enhancement of the downloaded file. Zootaxa 4555 (4): 491–506 ISSN 1175-5326 (print edition) https://www.mapress.com/j/zt/ Article ZOOTAXA Copyright © 2019 Magnolia Press ISSN 1175-5334 (online edition) https://doi.org/10.11646/zootaxa.4555.4.2 http://zoobank.org/urn:lsid:zoobank.org:pub:D3B7A64B-3F47-4B0D-9F4D-5F6DB028BEFE Laevistrombus Abbott 1960 (Gastropoda: Strombidae): Indian and southwest Pacific species STEPHEN J. MAXWELL1, AART M. DEKKERS2, TASMIN L. RYMER1,3 & BRADLEY C. CONGDON1,3 1College of Science and Engineering, James Cook University, Cairns Qld 4870. E-mail: [email protected] 2Oasestraat 79, 1448 NR, Pumerend, The Netherlands. 3Centre for Tropical Environmental and Sustainability Sciences, James Cook University, Cairns Qld 4870. Abstract Here we evaluate the taxonomy of the marine gastropod genus Laevistrombus Abbott, 1960 and determine that there are five extant species within this genus, three of which occur in the southwest Pacific. Comparative analyses of this complex have been problematic due to the lack of designated type material. Therefore, we present the type material for L. canarium Linnaeus, 1758; L. taeniatus Quoy & Gaimard, 1834; and L. vanikorensis Quoy & Gaimard, 1834. Current taxonomy has L. vanikorensis absorbed within the L. canarium complex. L. taeniatus is generally held to be a synonym of L. turturella Röding, 1789. We demonstrate that both L. taeniatus and L. vanikorensis are distinct species and reinstate both to species level. Our revision also notes the significant variability in early teleoconch structure within the geographic range of L. vanikorensis, and highlights the need for a greater revision of Laevistrombus, given the diversity in early teleoconch mor- phology present in southwest Pacific species. Key words: Laevistrombus, sympatric, taxonomy, revision, species, southwestern Pacific Introduction After the first major modern revision of the gastropod family Strombidae (Abbott 1960) the genus Laevistrombus Abbott, 1960 was generally accepted to contain a single extant species. However, the genus has undergone more recent revisions and it is now considered that Abbott (1960) was too conservative in his assessment (Man in’T Veld & de Turck 1998; Kreipl et al. 1999; Liverani 2013). These recent revisions currently recognise three extant taxa, namely L. canarium Linnaeus, 1758, L. guidoi Man in’T Veld & de Turck, 1998 and L. turturella Röding, 1789, although the rank of some taxa is in dispute (Liverani 2013). After further reviewing this complex, we recommend that two more Laevistrombus species, which are currently treated as synonyms post Abbott (1960), should be recognised as distinct species. The first, Laevistrombus vanikorensis Quoy & Gaimard, 1834 is currently considered a synonym of L. canarium. The second, L. taeniatus Quoy & Gaimard, 1834 is currently included under the synonymy of L. turturella (Figure 1). The reinstatement of these two species brings the total number of southwestern Pacific Laevistrombus species to three, and the total number of extant Laevistrombus species recognised worldwide to five. We note that L. guidoi and L. taeniatus are sympatric with L. vanikorensis in the southwestern Pacific region. Methods and materials We reviewed the taxonomy of taxa contained currently under the synonymy of L. canarium from first principles. This process involved the identification of all known names given to a targeted set of organisms from the southwest Pacific and India. This search was optimised by using historical reviews from which we could draw a preliminary list of names (Abbott 1960; Man in ‘T Veld & de Turck 1998). Once this list had been devised, it was Accepted by T. Duda: 3 Oct. 2018; published: 15 Feb. 2019 491 chronologically ordered and the descriptions examined alongside images of types or material referenced in the original descriptions. The information obtained was then chronologically compared, from earliest to latest and the defining characteristics of preceding taxa compared with later. From this comparison a new list of valid taxa was generated based on morphological and spatiotemporal characteristics. The reference lists of all articles were examined for any literature that may have been overlooked originally. This process of type material check, followed by literary internal content and reference search, was repeated for each name on the preliminary list. In the case of taxa that were described based on reference images, such as those species named by Linnaeus (1758) or Röding (1798), these reference images were examined and critiqued to ascertain a general theme or descriptive intent. This critique was presented along with translations of the original descriptions. Finally, all southwest Pacific valid taxa were then presented with original descriptions, type images and information on type locality. FIGURE 1. The Laevistrombus of Quoy and Gaimard (1834): A) L. canarium (Quoy and Gaimard 1834, pl. 51, fig. 10); B) Lectotype: L. vanikorensis (Quoy and Gaimard 1834, pl. 51, figs. 7 and 8); and C) Lectotype: L. taeniatus (Quoy and Gaimard 1834, pl. 51, figs. 14 and 15). 492 · Zootaxa 4555 (4) © 2019 Magnolia Press MAXWELL ET AL. Once the full species list was derived, those taxa on the list were compared to material in systematic collections to determine if the revised taxa reflected the natural diversity. This was achieved by first examining the original descriptions to determine the intent of the author in naming the organism. In this way, after examination of a larger sample of material, some taxa could be seen to reflect only regional colour forms, or the edges of a highly variable morphological cline and these were subsequently synonymised. Secondary references that did not add further information to the original descriptions, nor comprise major revisions, or contain new generic arrangements, were excluded from the synonymic list. Once the species list for the southwest Pacific was finalised and mapped, the immediate post-nuclear whorls, the early teleoconch, were examined and photographed for comparative studies to confirm species hypotheses. Abbreviations and Acronyms: AMD Collection of Aart M. Dekkers, Pumerend, The Netherlands. SM Collection of Stephen Maxwell, Cairns, Queensland, Australia. TM Collection of Trevor and Marguerite Young, Whitsundays, Queensland, Australia. VC Collection of Valda Cantamessa, Proserpine, Queensland, Australia. LLength. Results The genus Laevistrombus in the southwestern Pacific contains three species that are currently synonymised or seen as subspecies of L. canarium or L. turturella (Abbott 1960; Man in ‘T Veld & de Turck 1998; Liverani 2013). We suggest that there are distinct differences among some of the synonymized forms that allow the discernment of five species (Table 1; Figure 2). The shell of L. vanikorensis is smaller than that of L. canarium (rarely exceeding 5cm). L. vanikorensis also consistently displays a pattern of dark zigzag lines on a white background across the body of the shell and also on the posterior edge of the outer lip when viewed dorsally. This patterning terminates below the final suture. The dorsal lines are broader, less numerous, and darker than the Indian examples. L. vanikorensis has a less rotund body whorl lacking the high inflated shoulder of the dorsum. While the teleoconch of L. canarium is similar to that of some examples of L. vanikorensis, this is not a consistent feature, with the teleoconch of L. vanikorensis showing great diversity in form (Figure 3). The shell of L. taeniatus differs from L. turturella in having a uniform tan to brown colour, with a grey-blue mid-dorsal band, and an outer lip that is posteriorly more rounded. In contrast, the outer lip of L. turturella is more quadrate. While both species have spiral threads on the teleoconch, L. taeniatus does not have distinctive axial plaits that are present in L. turturella, which has a more angulate teleoconch shoulder (Figure 3). Restricted to Vanuatu, the endemic species L. guidoi differs from L. vanikorensis primarily in the teleoconch, which is more shouldered, with less defined spiral threads (Figure 3). The posterior outer lip of L. guidoi tends to be more calloused and axially recurved than L. vanikorensis. Both species show similarities in pattern when present; however, white shells are uncommon in L. vanikorensis, whereas patterning on the shell is rare in L. guidoi. Recent reviews have relegated the species L. guidoi to sub-specific rank under L. canarium (Liverani 2013). However, Liverani