Research Article |
Corresponding author: Ronald Vonk ( ronald.vonk@naturalis.nl ) Academic editor: Charles Oliver Coleman
© 2014 Ronald Vonk, Damia Jaume.
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:
Vonk R, Jaume D (2014) Ingolfiella maldivensis sp. n. (Crustacea, Amphipoda, Ingolfiellidae) from coral reef sand off Magoodhoo island, Maldives. ZooKeys 449: 69-79. https://doi.org/10.3897/zookeys.449.8544
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A new species of marine interstitial wormshrimp, Ingolfiella maldivensis, is described from coral sand on the inner and outer reef off Magoodhoo island, Faafu atoll, Maldives. Six females were found and compared to other species from the Maldives and those bordering the Indian Ocean and beyond. Morphological resemblance ties it to a species from the Caribbean island of Curaçao. Both species are found in shallow sublittoral interstitial spaces.
Taxonomy, sublittoral, interstitial habitat, dive sampling, atolls, Indian Ocean
The Maldive Islands (Central Indian Ocean) consist of a 800-km long string of 22 atolls containing an extensive coral reef system topped by over a thousand islands (
The first Maldives Coral Reef Biodiversity Workshop located at MARHE Centre in Magoodhoo (May 2014) enabled sampling by use of SCUBA and access to a wide variety of suitable habitats for reef coral rubble inhabitants. Previously, only two other specimens of representatives of the family had been reported from the Maldives (
Although their numbers are mostly low, the presence of vermiform and interstitial ingolfiellids or wormshrimps (
In this paper we describe Ingolfiella maldivensis sp. n. and discuss relations to other species.
The six specimens of the new species were collected from two different sites (Fig.
The samples were sorted in the Italian field station of the Milano-Bicocca Marine Research and High Education Centre (MARHE) under a dissecting microscope and transferred to 96% ethanol. Before study, specimens were treated with lactic acid to soften the cuticle and remove internal tissues to facilitate observation. Photo of entire animal (Fig.
One specimen, RMNH.CRUS.P.264, female paratype 1.85 mm, at station ‘Blu Cove’, 6 May 2014, depth 15 m, N3°05'37.8", E72°57'59.4". Five specimens: RMNH.CRUS.P.265, undissected female holotype 1.80 mm (Fig.
Lateral lobes on frontal margin of the head present. Dactyls of gnathopods armed with four javelin lancet shaped bladelike spines along posterior margin. Palm of G2 angle robust seta bifid; posteromedial surface of carpus lacking broad triangular spine. Medial surface of protopod of U2 with three denticle combs. Unguis of P3–P4 with four denticles; that of P5–P7 bifid. PL1–PL3 present and of similar form. Oostegites on P3–P4.
The new species is named after the group of islands where it was found, in the Republic of the Maldives.
Body elongate, cylindrical, without coloration, transparent to milky white (Fig.
Ingolfiella maldivensis sp. n., holotype female 1.80 mm A cephalic lobe B antennule C paratype female 1.85 mm, antenna D paratype female 1.55 mm, labrum E right mandible with incisor and molar process F maxillule G maxilla H maxilliped I paratype 1.85 mm, right gnathopod 1, medial J right gnathopod 2, medial (inset: palm margin of holotype 1.80 mm).
Antennule (Fig.
Antenna (Fig.
Labrum (Fig.
Mandibles with molar process non-triturative, spiniform and not serrated. Right mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
Coxal gills (Fig.
Gnathopod 1 (Fig.
Gnathopod 2 (Fig.
Pereiopods 3–4 (Fig.
Pereiopods 5–7 (Fig.
Pleopods 1–3 (Fig.
Uropod 1 (Fig.
Uropod 2 (Fig.
Uropod 3 (Fig.
Telson (Fig.
Previous knowledge on the ingolfiellids from the Maldives was restricted to specimens collected during the Xarifa Expedition 1957–1958. These came from washings of the coral Favites sp. (
A comparison of fourteen easy to distinguish characters between members of the genus Ingolfiella (45 species) was done by
Other species bordering the Indian Ocean include: I. kapuri Coineau & Rao, 1973, from the Andaman and Nicobar Islands in intertidal shell debris; I. arganoi Iannilli & Vonk, 2013 from Abd-al-Kuri Island, Socotra Archipelago in an anchialine pool; I. quokka Gallego-Martínez & Poore, 2003, from an intertidal sandy beach environment from the City of York Bay, Western Australia. All of these species differ sharply from I. maldivensis (see
The recently described I. botoi Vonk & Jaume, 2014, from beach groundwater in the Gura Ici Islands, Molucca Sea, Indonesia (
Repeated visits to the same island groups or to mainland karst areas have often revealed additional species each time a specific search for ingolfiellids was made. In other cases populations of the same species are spread over different islands. This was encountered in the Canary islands for the widely separated islands Hierro and Tenerife (
These examples lead to the expectation that an ocean spanning, circumtropical continuum exists of populations gradually changing in minor morphological adaptations and converging in functional form toward their environment. Such convergence could explain why a sublittoral reef sand inhabiting form from the Caribbean is more similar to a form that lives in comparable micro-habitats in the Indian Ocean, than it is to a congener (I. grandispina Stock, 1979) found a few kilometers away in a brackish cave bottom with other functional requirements to form. This convergent development can be observed in the close morphological resemblance of I. quadridentata from the Caribbean island of Curacao and the species, described in this study, I. maldivensis. They both come from sublittoral reef sands.
The Maldives have undergone dramatic sealevel changes (
The Dutch Society for the advancement of research in the tropics (Treub-Maatschappij) is gratefully acknowledged for its financial support. We are also obliged to the University of Milano-Bicocca Marine Research and High Education Centre in Magoodhoo, the Ministry of Fisheries and Agriculture, Republic of Maldives and the community of Magoodhoo, Faafu Atoll, for providing means and assistance; Francesca Benzoni and Paolo Galli for organisation of the Workshop; Simone Montano, Davide Seveso, and Andrea Di Pietro for dive support. Bert Hoeksema is thanked for improving the ms; Kees van den Berg for microscopy techniques and photos, and two anonymous reviewers for constructive comments.