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Shin CP, Allmon WD. How we study cryptic species and their biological implications: A case study from marine shelled gastropods. Ecol Evol 2023; 13:e10360. [PMID: 37680961 PMCID: PMC10480071 DOI: 10.1002/ece3.10360] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/10/2023] [Accepted: 07/13/2023] [Indexed: 09/09/2023] Open
Abstract
Methodological and biological considerations are intertwined when studying cryptic species. A potentially large component of modern biodiversity, the frequency of cryptic species among taxonomic groups is not well documented. The term "cryptic species" is imprecisely used in scientific literature, causing ambiguity when interpreting their evolutionary and ecological significance. This study reviews how cryptic species have been defined, discussing implications for taxonomy and biology, and explores these implications with a case study based on recently published literature on extant shelled marine gastropods. Reviewed gastropods were recorded by species. Records of cryptic gastropods were presented by authors with variable levels of confidence but were difficult to disentangle from inherent biases in the study effort. These complexities notwithstanding, most gastropod species discussed were not cryptic. To the degree that this review's sample represents extinct taxa, the results suggest that a high proportion of shelled marine gastropod species are identifiable for study in the fossil record. Much additional work is needed to provide a more adequate understanding of the relative frequency of cryptic species in shelled marine gastropods, which should start with more explicit definitions and targeted case studies.
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Affiliation(s)
- Caren P. Shin
- Department of Earth and Atmospheric SciencesCornell UniversityIthacaNew YorkUSA
- Paleontological Research InstitutionIthacaNew YorkUSA
| | - Warren D. Allmon
- Department of Earth and Atmospheric SciencesCornell UniversityIthacaNew YorkUSA
- Paleontological Research InstitutionIthacaNew YorkUSA
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2
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Lan Y, Sun J, Chen C, Wang H, Xiao Y, Perez M, Yang Y, Kwan YH, Sun Y, Zhou Y, Han X, Miyazaki J, Watsuji TO, Bissessur D, Qiu JW, Takai K, Qian PY. Endosymbiont population genomics sheds light on transmission mode, partner specificity, and stability of the scaly-foot snail holobiont. THE ISME JOURNAL 2022; 16:2132-2143. [PMID: 35715703 PMCID: PMC9381778 DOI: 10.1038/s41396-022-01261-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 11/28/2022]
Abstract
The scaly-foot snail (Chrysomallon squamiferum) inhabiting deep-sea hydrothermal vents in the Indian Ocean relies on its sulphur-oxidising gammaproteobacterial endosymbionts for nutrition and energy. In this study, we investigate the specificity, transmission mode, and stability of multiple scaly-foot snail populations dwelling in five vent fields with considerably disparate geological, physical and chemical environmental conditions. Results of population genomics analyses reveal an incongruent phylogeny between the endosymbiont and mitochondrial genomes of the scaly-foot snails in the five vent fields sampled, indicating that the hosts obtain endosymbionts via horizontal transmission in each generation. However, the genetic homogeneity of many symbiont populations implies that vertical transmission cannot be ruled out either. Fluorescence in situ hybridisation of ovarian tissue yields symbiont signals around the oocytes, suggesting that vertical transmission co-occurs with horizontal transmission. Results of in situ environmental measurements and gene expression analyses from in situ fixed samples show that the snail host buffers the differences in environmental conditions to provide the endosymbionts with a stable intracellular micro-environment, where the symbionts serve key metabolic functions and benefit from the host’s cushion. The mixed transmission mode, symbiont specificity at the species level, and stable intracellular environment provided by the host support the evolutionary, ecological, and physiological success of scaly-foot snail holobionts in different vents with unique environmental parameters.
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Affiliation(s)
- Yi Lan
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jin Sun
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Chong Chen
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Prefecture, Japan
| | - Hao Wang
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yao Xiao
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Maeva Perez
- Department of Biological Sciences, University of Montreal, Montreal, Quebec, Canada
| | - Yi Yang
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yick Hang Kwan
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yanan Sun
- Department of Biology and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Yadong Zhou
- Key Laboratory of Marine Ecosystem Dynamics & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Xiqiu Han
- Key Laboratory of Submarine Geosciences & Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, 310012, China
| | - Junichi Miyazaki
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Prefecture, Japan
| | - Tomo-O Watsuji
- Department of Food and Nutrition, Higashi-Chikushi Junior College, 5-1-1 Shimoitozu, Kitakyusyu, 803-0846, Japan
| | - Dass Bissessur
- Department for Continental Shelf, Maritime Zones Administration & Exploration, Prime Minister's Office, 2nd Floor, Belmont House, 12 Intendance Street, Port Louis, 11328, Mauritius
| | - Jian-Wen Qiu
- Department of Biology and Hong Kong Branch of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Ken Takai
- X-STAR, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, 237-0061, Kanagawa Prefecture, Japan
| | - Pei-Yuan Qian
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China. .,Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China.
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Linse K, Sigwart JD, Chen C, Krylova EM. Ecophysiology and ecological limits of symbiotrophic vesicomyid bivalves (Pliocardiinae) in the Southern Ocean. Polar Biol 2020. [DOI: 10.1007/s00300-020-02717-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
AbstractGeothermal energy provides an important resource in Antarctic marine ecosystems, exemplified by the recent discovery of large-sized chemosymbiotic vesicomyid bivalves (subfamily Pliocardiinae) in the Southern Ocean. These clams, which we identified as Archivesica s.l. puertodeseadoi, have been reported as dead shells in areas previously covered by Larsen A and B ice shelves (eastern Antarctic Peninsula) and as live animals from active hydrothermal sites in the Kemp Caldera (South Sandwich Arc) at depths of 852–1487 m. Before, A. puertodeseadoi was known only from its type locality in the Argentine Sea, so we considerably extend the range of the species. Observations taken by remotely operated vehicle (ROV) footage show that the clams can live buried in sediment, or epilithically on the surface of rocks in diffuse geothermal flow. Experimental respirometry was conducted at surface pressure on individual bivalves acclimated to either their habitat temperature (4 °C) or elevated temperature (10 °C). The range of standard metabolic rates, from 3.13 to 6.59 (MO2, μmol O2 h−1 g−1 dry tissue mass), is similar to rates measured ex situ for other species in this clade, and rates did not differ significantly between temperature groups. Taken together, these data indicate a range of ecophysiological flexibility for A. puertodeseadoi. Although adapted to a specialist mode of life, this bivalve exploits a relatively broad range of habitats in the Southern Ocean: within sulphidic sediments, epilithically in the presence of diffuse sulphidic flow, or in deep methane-enriched seawater trapped under ice.
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Laming SR, Hourdez S, Cambon-Bonavita MA, Pradillon F. Classical and computed tomographic anatomical analyses in a not-so-cryptic Alviniconcha species complex from hydrothermal vents in the SW Pacific. Front Zool 2020; 17:12. [PMID: 32391066 PMCID: PMC7203863 DOI: 10.1186/s12983-020-00357-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/16/2020] [Indexed: 01/21/2023] Open
Abstract
The chemosymbiotic gastropod Alviniconcha (Provannidae), first described in 1988, is one of the most emblematic hydrothermal-vent taxa described from the Central Indian Ridge and the Southwest (SW) Pacific. Symbiotic bacteria found in the gill of Alviniconcha are thought to be their principal source of nutrition. In the SW Pacific, species distributions for A. kojimai, A. boucheti - and to a lesser extent A. strummeri - overlap. While Alviniconcha species do not appear to truly co-exist in these highly energetic but spatially limited habitats, certain species regularly co-occur within a single vent field and in rare instances, the same edifice. Past research suggests that SW-Pacific Alviniconcha species might aggregate around fluids with distinct geothermal profiles. These small-scale distribution patterns have been attributed to differences in their symbiont assemblages or host physiologies. However, little is known about the anatomy of most Alviniconcha species, beyond that detailed for the type species Alviniconcha hessleri, whose geographic range does not overlap with other congeners. In fact, species within this genus are currently described as cryptic, despite the absence of any comparative morphological studies to assess this. To test whether the genus is genuinely cryptic and identify any functional differences in host anatomy that might also mediate habitat partitioning in SW Pacific species, the current study examined the morphoanatomy of A. kojimai, A. boucheti and A. strummeri from the Fatu Kapa vent field, an area of hydrothermal activity recently discovered north of the Lau Basin near the Wallis and Futuna Islands and the only known example where all three species occur within adjacent vent fields. A combination of detailed dissections, histology and X-ray computed tomography demonstrate that A. kojimai, A. strummeri and A. boucheti are readily identifiable based on shell morphology and ornamentation alone, and therefore not truly cryptic. These traits provide a rapid and reliable means for species identification. However, aside from some subtle differences in radular morphology, these species of Alviniconcha exhibit conserved anatomical features, providing no evidence that functional host anatomy is implicated in habitat partitioning. This provides support for the current belief that host-species distributions are probably governed by symbiont-mediated physiological factors.
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Affiliation(s)
- Sven R Laming
- 1Ifremer, Laboratoire Environnement Profond (REM/EEP/LEP), Plouzané, France.,2Ifremer, Univ Brest, CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes (REM/EEP/LM2E), Plouzané, France.,3Current address: LEME, CESAM - Centre for Environmental and Marine Studies, Department of Biology, Universidade de Aveiro, Santiago Campus, 3810-193 Aveiro, Portugal
| | - Stéphane Hourdez
- 4UMR 8222 CNRS-Sorbonne Université, Laboratoire d'écogéochimie des environnements benthiques (LECOB), Banyuls-sur-Mer, France
| | - Marie-Anne Cambon-Bonavita
- 2Ifremer, Univ Brest, CNRS, UMR6197, Laboratoire de Microbiologie des Environnements Extrêmes (REM/EEP/LM2E), Plouzané, France
| | - Florence Pradillon
- 1Ifremer, Laboratoire Environnement Profond (REM/EEP/LEP), Plouzané, France
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Chen C, Linse K, Uematsu K, Sigwart JD. Cryptic niche switching in a chemosymbiotic gastropod. Proc Biol Sci 2018; 285:20181099. [PMID: 30051825 PMCID: PMC6053925 DOI: 10.1098/rspb.2018.1099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/15/2018] [Indexed: 12/25/2022] Open
Abstract
Life stages of some animals, including amphibians and insects, are so different that they have historically been seen as different species. 'Metamorphosis' broadly encompasses major changes in organism bodies and, importantly, concomitant shifts in trophic strategies. Many marine animals have a biphasic lifestyle, with small pelagic larvae undergoing one or more metamorphic transformations before settling into a permanent, adult morphology on the benthos. Post-settlement, the hydrothermal vent gastropod Gigantopelta chessoia experiences a further, cryptic metamorphosis at body sizes around 5-7 mm. The terminal adult stage is entirely dependent on chemoautotrophic symbionts; smaller individuals do not house symbionts and presumably depend on grazing. Using high-resolution X-ray microtomography to reconstruct the internal organs in a growth series, we show that this sudden transition in small but sexually mature individuals dramatically reconfigures the organs, but is in no way apparent from external morphology. We introduce the term 'cryptometamorphosis' to identify this novel phenomenon of a major body change and trophic shift, not related to sexual maturity, transforming only the internal anatomy. Understanding energy flow in ecosystems depends on the feeding ecology of species; the present study highlights the possibility for adult animals to make profound shifts in biology that influence energy dynamics.
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Affiliation(s)
- Chong Chen
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 2370061, Japan
| | - Katrin Linse
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
| | - Katsuyuki Uematsu
- Marine Works Japan Ltd., 3-54-1 Oppamahigashi, Yokosuka, Kanagawa 2370063, Japan
| | - Julia D Sigwart
- Marine Laboratory, Queen's University Belfast, 12-13 The Strand, Portaferry BT22 1PF, N. Ireland
- Museum of Paleontology, University of California, Berkeley, CA 94720, USA
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