Research Article |
Corresponding author: Francisco Alonso Solís-Marín ( fasolis@cmarl.unam.mx ) Academic editor: Didier Vanden Spiegel
© 2023 Francisco Alonso Solís-Marín, Carlos Andrés Conejeros-Vargas, Andrea Alejandra Caballero-Ochoa, Sheila Colleen Byers.
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:
Solís-Marín FA, Conejeros-Vargas CA, Caballero-Ochoa AA, Byers SC (2023) Epitomapta aumakua sp. nov., a new species of apodous sea cucumber from Hawai`i (Echinodermata, Holothuroidea, Apodida). ZooKeys 1183: 73-80. https://doi.org/10.3897/zookeys.1183.111620
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Epitomapta aumakua sp. nov. occurs at a depth of 2.5 m in Kualoa, O`ahu, Hawai`i, living in coarse sand. It is distinctive in having 12 pinnate tentacles, each tentacle with three pairs of digits and 6–8 sensory cups. The body wall bears papillae or oval bumps, and the length of body reaches a maximum length of 18.4 mm after relaxation.
Leptosynaptinae, Synaptidae, taxonomy
The apodous sea cucumbers of the subfamily Leptosynaptinae Smirnov, 1989 (Apodida Brandt, 1835; Synaptidae Burmeister, 1837) are interstitial organisms that inhabit intertidal and shallow waters. They have a vermiform, translucent integument (
Specimens are preserved in the
Marine Invertebrate Collection of the Beaty Biodiversity Museum, University of British Columbia, Canada (
Order Apodida Brandt, 1835
Family Synaptidae Burmeister, 1837
Pinnate tentacles 10, 11 or 12, with 1–9 digits on each side. Digits increase in size from base to tip of tentacle. Anchor plate develops from a rod which lies at a right angle to stock of developing anchor. Anchor plates with small number of holes, usually seven (6+1) in main part of the plate: six holes form a circle around a central hole. Articular end of plate usually has a “ledge” for contact with anchor keel. Anchor arms regularly serrated, rarely smooth, and without minute knobs on the vertex (
Tentacles pinnate, usually 12. Digits in 2–5 pairs on each side (rarely two or none). Sense organs never in form of pigment-eyes, but as minute cups on inner face of stalk of tentacles. Calcareous ring well developed. Radial pieces not perforated for passage of nerves, but with an anterior notch. Cartilaginous ring absent. Polian vesicle usually single. Stone canal single, unbranched. Ciliated funnels of different shapes and attached to body wall, not to mesenteries. Calcareous deposits in body wall are anchors, anchor plates and miliary granules; tentacles with rods only. Stock of anchors finely toothed, but not branched; arms usually with teeth on outer edge; vertex smooth. Anchor plates oval, with large central hole, surrounded by six large holes, usually more or less dentate, and two large and several small smooth holes at narrow posterior end, but without an arched bow crossing outer surface; broad end often with additional dentate holes (
Epitomapta tabogae Heding, 1928 by original designation.
Holotype.
Off Kualoa, O`ahu, Hawai`i, Pacific Ocean 21°30'N, 157°50'W.
Body wall smooth, covered with small, oval-circular bumps, especially on anterior part of body. Tentacles 12, each with three pairs of lateral digits and a terminal digit; 6–8 sensory cups on each tentacle. Polian vesicle, 1/10 of body length; stone canal single, unbranched. Anchor and anchor plates of one kind: anchors usually exceeding 170 µm in length, plates exceeding 110 µm in length. Miliary granules scarce, only present in longitudinal muscles, relatively coarse, usually in form of simple flat, often faintly undulating, stout, straight rods with enlarged ends, slightly bent but never C-shaped, usually exceeding 20 µm in length. Tentacle ossicles shaped like smooth, flattened rods, not exceeding 50 µm in length, curved, with perforated ends; some rods broad (ca 14 µm in width) with few circular peripheral holes.
18.4 mm long. Specimen uniformly whitish, body wall translucent when expanded. Anchors (Fig.
Ossicles. Body-wall deposits comprise anchors and anchor plates (Fig.
Paratype variations. Specimens range from 16–17 mm in length.
The specific epithet aumakua refers, in Hawaiian mythology, to a person or family god that originated as a deified ancestor, who takes on physical forms as spirit vehicles. Here it is used as a non-Latin noun in apposition.
Epitomapta aumakua sp. nov. occurs at 2.5 m depth, buried in coarse sand.
Known only from its type locality.
Epitomapta aumakua sp. nov. is very similar to its central Eastern Pacific congener E. simentalae but differing in the number of sensory cups per tentacle (4–6 in E. simentalae, 6–8 in E. aumakua sp. nov.). In addition to the geographical distribution, E. aumakua sp. nov. is smaller (<20 mm) than E. simentalae (<50 mm) (
The anchors of the body wall in E. aumakua sp. nov. are similar in shape to those of E. roseola, but they differ in size, being approximately 160–170 μm long and 76–80 μm wide in E. aumakua sp. nov. (Fig.
Epitomapta aumakua sp. nov. is clearly distinguished from other species of the genus in having extremely large anchors, a character that has been used to differentiate species of the genus by various authors (see
1 | Papillae or oval bumps present all over the body wall | 2 |
– | Papillae or oval bumps absent. With 2–3 pairs of tentacle digits, each tentacle with 4–6 sensory cups. Miliary granules in the shape of small, C- and O-shaped bodies; no papillae or oval bumps present on the body wall | E. simentalae |
2 | Atlantic Ocean. With 7 pairs of tentacle digits, each tentacle with 2–5 sensory cups. Anchors of body wall exceed 120 μm in length (up to 150 μm). Miliary granules in the shape of small, oval rings and very few C-shaped bodies | E. roseola |
– | Pacific Ocean | 3 |
3 | Central America (Panama). With 5–6 pairs of tentacle digits, each tentacle with 8–14 sensory cups. Anchors of body wall exceed 120 μm in length (up to 200 μm). Miliary granules in the shape of oval rings and very few C-shaped bodies | E. tabogae |
– | Eastern Indo Pacific (Hawai`i). With 3 pairs of tentacle digits, each tentacle with 6–8 sensory cups. Anchors of body wall exceed 150 μm in length. Scarce miliary granules in the shape of stout, flat rods | E. aumakua sp. nov. |
We thank Dr Hugh MacIntosh, collection manager of Invertebrate Zoology, Royal British Columbia for granting access to FASM to the collection under his responsibility. It is with great pleasure that we thank Dr Yves Samyn and Dr Rafael B. de Moura for critically reviewing the manuscript. We also thank Derrick Horne, BioImaging Facility, University of British Columbia, for his technical support with the scanning electron microscope. Finally, we thank Matthew G. Lovegrove for his valuable comments on the manuscript’s English.
The authors have declared that no competing interests exist.
No ethical statement was reported.
The first author (FASM) thanks the sabbatical fellowship from Programa de Apoyos para la Superación del Personal Académico, Dirección General de Asuntos del Personal Académicos, Universidad Nacional Autónoma de México (UNAM). Publication cost was provided by Instituto de Ciencias del Mar y Limnología, UNAM.
Francisco A. Solis-Marin: Investigation. Carlos A. Conejeros-Vargas: Investigation and imagen processing. Andrea A. Caballero-Ochoa: Investigation. Sheila Colleen Byres: Data analysis.
Francisco Alonso Solís-Marín https://orcid.org/0000-0001-5729-3316
Carlos Andrés Conejeros-Vargas https://orcid.org/0000-0003-0148-0475
Andrea Alejandra Caballero-Ochoa https://orcid.org/0000-0001-5520-3823
Sheila Colleen Byers https://orcid.org/0009-0003-7470-5193
All of the data that support the findings of this study are available in the main text.