Short Communication |
Corresponding author: Richard Greenfield ( rgreenfield@uj.ac.za ) Academic editor: Nathalie Yonow
© 2015 Herman Van Der Bank, Richard Greenfield.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
van der Bank H, Greenfield R (2015) A pioneer survey and DNA barcoding of some commonly found gastropod molluscs on Robben Island. ZooKeys 481: 15-23. https://doi.org/10.3897/zookeys.481.8188
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Nineteen species of abundant gastropods were collected at Robben Island, including introduced dune snails and European brown garden snails. They were identified using morphology and DNA barcoding. It was expected that the species recorded would be similar to those from the Cape peninsula, South Africa, but we were surprised to find some exceptions: the very abundant invasive mussel species in South Africa, the South American bisexual mussel (Semimytilus algosus), and the beaded topshells (Oxystele impervia) were not found on Robben Island. Possible explanations are presented for these differences.
Mollusca , Gastropoda , mitochondrial gene COI, species identification
Robben Island is most renowned for its maximum security prison, which housed President Nelson Mandela of SA. Robben Island is 7 km from Bloubergstrand (SA), the length of Robben Island is 5.4 km, the width is 2.5 km, and has an area of 574 hectares (approximately 5.74 km2) with the highest point at 30 m above sea level and an annual rain fall of between 300 mm and 400 mm. It is less known for being the island to which lepers were banned to become miserable island outcasts. The leper colony was initiated in 1846 with special water police patrols to ensure no escapees. Robben Island has recently become a tourist attraction, possibly contributing towards the decline of African penguin numbers to the extent that they became an endangered species (
Unfortunately, little research on molluscs has been carried out on the island. The only available reference is to one mussel species at Robben Island by
Samples were collected from random sampling sites during July 2011. Standard DNA barcoding protocols were used to ensure correct identification of individuals (e.g.
DNA extraction, polymerase chain reactions (PCR) and sequencing of the COI region (animal DNA barcode) were done at the Canadian Centre for DNA Barcoding (CCDB). Standard CCDB protocols for PCR reactions were followed as described by
We reconstructed Bayesian phylogenetic trees using MrBayes v3.1.2 (
PAUP* v4.10b10 (
Depending on availability, up to 10 individuals per species were collected (Table
BOLD process and sample identity numbers, species collected, authorities and families. Bold font indicates samples for which no DNA barcodes were obtained from BOLD.
BOLD Process | Sample identity | Species | Family |
---|---|---|---|
HVDBM476-11
HVDBM495-11 |
HVDBM-ROB-96 HVDBM-ROB-97 |
Afrolittorina knysnaensis (Philippi, 1847) | Littorinidae |
HVDBM569-11 | HVDBM-ROB-94 | Burnupena catarrhacta (Gmelin, 1791) | Buccinidae |
HVDBM528-11
HVDBM529-11 HVDBM530-11 HVDBM531-11 HVDBM532-11 |
HVDBM-ROB-53 HVDBM-ROB-54 HVDBM-ROB-55 HVDBM-ROB-56 HVDBM-ROB-57 |
Burnupena cincta (Röding, 1798) | Buccinidae |
HVDBM533-11
HVDBM534-11 HVDBM535-11 HVDBM536-11 HVDBM537-11 |
HVDBM-ROB-58 HVDBM-ROB-59 HVDBM-ROB-60 HVDBM-ROB-61 HVDBM-ROB-62 |
Cornu aspersum (Müller, 1774) | Helicidae |
HVDBM525-11
HVDBM526-11 HVDBM527-11 HVDBM553-11 HVDBM554-11 HVDBM555-11 HVDBM556-11 HVDBM568-11 |
HVDBM-ROB-50 HVDBM-ROB-51 HVDBM-ROB-52 HVDBM-ROB-78 HVDBM-ROB-79 HVDBM-ROB-80 HVDBM-ROB-81 HVDBM-ROB-93 |
Crepidula complanata (Krauss, 1848) | Calyptraeidae |
HVDBM496-11
HVDBM497-11 HVDBM552-11 |
HVDBM-ROB-21 HVDBM-ROB-22 HVDBM-ROB-77 |
Cymbula compressa (Linnaeus, 1758) | Patellidae |
HVDBM481-11
HVDBM482-11 HVDBM483-11 HVDBM484-11 HVDBM485-11 HVDBM486-11 HVDBM500-11 HVDBM540-11 HVDBM541-11 HVDBM542-11 |
HVDBM-ROB-06 HVDBM-ROB-07 HVDBM-ROB-08 HVDBM-ROB-09 HVDBM-ROB-10 HVDBM-ROB-11 HVDBM-ROB-25 HVDBM-ROB-65 HVDBM-ROB-66 HVDBM-ROB-67 |
Cymbula granatina (Linnaeus, 1758) | Patellidae |
HVDBM487-11
HVDBM488-11 HVDBM489-11 HVDBM539-11 |
HVDBM-ROB-12 HVDBM-ROB-13 HVDBM-ROB-14 HVDBM-ROB-64 |
Cymbula oculus (Born, 1778) | Patellidae |
HVDBM499-11
HVDBM570-11 |
HVDBM-ROB-24 HVDBM-ROB-95 |
Fissurella mutabilis (Sowerby, 1835) | Fissurellidae |
HVDBM561-11 | HVDBM-ROB-86 | Helcion pectunculus (Gmelin, 1791) | Patellidae |
HVDBM506-11
HVDBM507-11 HVDBM508-11 HVDBM509-11 HVDBM510-11 |
HVDBM-ROB-31 HVDBM-ROB-32 HVDBM-ROB-33 HVDBM-ROB-34 HVDBM-ROB-35 |
Oxystele tigrina (Anton, 1839) | Trochidae |
HVDBM511-11
HVDBM512-11 HVDBM513-11 HVDBM514-11 HVDBM515-11 |
HVDBM-ROB-36 HVDBM-ROB-37 HVDBM-ROB-38 HVDBM-ROB-39 HVDBM-ROB-40 |
Oxystele variegata (Anton, 1839) | Trochidae |
HVDBM498-11 | HVDBM-ROB-23 | Scutellastra barbara (Linnaeus, 1758) | Patellidae |
HVDBM477-11
HVDBM478-11 HVDBM479-11 HVDBM480-11 |
HVDBM-ROB-02
HVDBM-ROB-03 HVDBM-ROB-04 HVDBM-ROB-05 |
Scutellastra cochlear (Born, 1778) | Patellidae |
HVDBM490-11
HVDBM491-11 HVDBM492-11 HVDBM493-11 HVDBM494-11 HVDBM562-11 |
HVDBM-ROB-15 HVDBM-ROB-16 HVDBM-ROB-17 HVDBM-ROB-18 HVDBM-ROB-19 HVDBM-ROB-87 |
Scutellastra granularis (Linnaeus, 1758) | Patellidae |
HVDBM563-11
HVDBM564-11 HVDBM565-11 HVDBM566-11 |
HVDBM-ROB-88 HVDBM-ROB-89 HVDBM-ROB-90 HVDBM-ROB-91 |
Siphonaria serrata (Fischer von Waldheim, 1807) | Siphonariidae |
HVDBM501-11
HVDBM502-11 HVDBM503-11 HVDBM504-11 HVDBM505-11 |
HVDBM-ROB-26 HVDBM-ROB-27 HVDBM-ROB-28 HVDBM-ROB-29 HVDBM-ROB-30 |
Siphonaria oculus (Krauss, 1848) | Siphonariidae |
HVDBM538-11
HVDBM1129-12 HVDBM1130-12 HVDBM1131-12 HVDBM1132-12 HVDBM1133-12 |
HVDBM-ROB-63 HVDBM_ROB_1010 HVDBM_ROB_1011 HVDBM_ROB_1012 HVDBM_ROB_1013 HVDBM_ROB_1014 |
Theba pisana (Müller, 1774) | Helicidae |
HVDBM1134-12
HVDBM1135-12 HVDBM1136-12 HVDBM1137-12 HVDBM1138-12 |
HVDBM_ROB_1015 HVDBM_ROB_1016 HVDBM_ROB_1017 HVDBM_ROB_1018 HVDBM_ROB_1019 |
Trigonephrus globulus (Müller, 1774) | Dorcasiidae |
HVDBM551-11 | HVDBM-ROB-76 | Turbo cidaris (Gmelin, 1791) | Turbinidae |
An unedited BOLD identification tree of barcoded southern African individuals is available from the corresponding author. This includes 815 sequenced individuals from 184 species, 118 genera, and 76 families in southern Africa (excluding the ones that were published already in other journals such as in
BOLD process and sample identity numbers, species collected, authorities and families are listed in Table
The most abundant terrestrial snail we encountered was Theba pisana (Müller, 1774), an introduced dune snail. As expected, more Cape endemic terrestrial snails were found (Trigonephrus globulus, Müller, 1774) and fewer introduced European brown garden snails (Cornu aspersum, Müller, 1774, formerly Helix aspersa) were recorded. Figure
Approximately 85–90% of the habitat at the coast consists of rocky shores, with low biodiversity of sparsely populated barnacles and molluscs (bivalves, limpets, and mussels): it consisted mostly of individuals of the same species. According to the island conservationists, this can be attributed to the rough seas.
We were pleasantly surprised not to have found any South American bisexual mussel on Robben Island, as they are extremely common on the SA coastline (only approximately 6.9 km away) and Robben Island was joined with SA approximately 10 000 years ago (
At the generic level, all of the marine species are monophyletic and were well supported (bootstrap values 98–100%; Figure
We were also surprised not to find any Oxystele impervia (Menke, 1843) individuals on the island, which could be due to differences in habitat preferences: they are found more abundantly higher up the shore than, for example, O. variegata (
The slipper-limpet (Crepidula complanata Krauss, 1848) was found with smaller males on top of the larger females; both live on other shells but are not parasites. Two clades with 91% and 97% bootstrap support were obtained (Figure
Almost no molluscs occurred on the man-made structures surrounding the harbour, most probably because these were installed recently, in 2004. This area was studied because introductions from ships (which transport tourists from SA as well as island staff and children) are most likely to occur at the harbour.
Surveys that are much more detailed are required to report on the biodiversity of the island; however, this is the first study to link DNA sequence results with the morphology of the commonly found molluscs on Robben Island and thereby to contribute to the global biodiversity fauna data that could enhance future efforts in conservation and management.
We thank the Government of Canada through Genome Canada and the Ontario Genomics Institute (2008-OGI-ICI-03) for the DNA sequencing, Estelle Esterhuizen (Robben Island Nature Conservation) for assistance with sample collections and the National Research Foundation of South Africa for financial support. We thank Prof Dai Herbert (Curator: KwaZulu-Natal Museum, South Africa) and Linda Davis for identification and housing of the shells, and Prof Michelle van der Bank with assistance in data analyses.