On a new commensal species of Aliaporcellana from the western Pacific (Crustacea, Decapoda, Porcellanidae)

A peer-reviewed open-access journal ZooKeys 780: 1–9 (2018) On a new commensal species of Aliaporcellana from the western Pacific... doi: 10.3897/zookeys.780.26388 RESEARCH ARTICLE http://zookeys.pensoft.net 1 Launched to accelerate biodiversity research On a new commensal species of Aliaporcellana from the western Pacific (Crustacea, Decapoda, Porcellanidae) Alexandra Hiller1, Bernd Werding2 1 Smithsonian Tropical Research Institute, Apartado 0843–03092, Panamá, República de Panamá 2 Institut für Tierökologie und Spezielle Zoologie der Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 29 (Tierhaus), D-35392 Giessen, Germany Corresponding author: Alexandra Hiller () Academic editor: I. Wehrtmann | Received 3 May 2018 | Accepted 18 July 2018 | Published 8 August 2018 http://zoobank.org/6A7C9B46-8674-44CE-99E7-4F819952E893 Citation: Hiller A, Werding B (2018) On a new commensal species of Aliaporcellana from the western Pacific (Crustacea, Decapoda, Porcellanidae). ZooKeys 780: 1–9. https://doi.org/10.3897/zookeys.780.26388 Abstract Aliaporcellana spongicola sp. n. from the Philippines and Indonesia is described. The new species has been frequently photographed by divers because of its striking coloration, but has not been described yet. Aliaporcellana spongicola sp. n. is in fact a widespread commensal of barrel sponges of the genus Xestospongia and other sponges. Morphological characters and ecological information of all described species of Aliaporcellana, and of other porcellanids associated with sponges and soft corals, suggest that all members of the genus are commensals, and that similar morphological adaptations to dwelling on these hosts have evolved independently in different evolutionary lines within Porcellanidae. Keywords Crustacea, Porcellanidae, Aliaporcellana, new species, Indo-West Pacific, commensalism, adaptation, sponge- and octocoral-dwelling Introduction The porcellanid genus Aliaporcellana was established by Nakasone and Miyake (1969) for a group of Indo-West Pacific species previously assigned to Porcellana Lamarck and to one of three natural groups within Polyonyx Stimpson, designated by Johnson (1958) as the P. denticulatus Paul’son 1875, group. A diagnostic character considered Copyright Alexandra Hiller, Bernd Werding. 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. 2 Alexandra Hiller & Bernd Werding / ZooKeys 780: 1–9 (2018) by Nakasone and Miyake (1969) to raise Aliaporcellana is the dactylus of all walking legs bearing two or more distinctively well-developed fixed spines. Aliaporcellana contained nine species until Haig (1978) restricted the genus to the species of the Polyonyx denticulatus group, which now includes the type A. suluensis (Dana 1852), A. pygmaea (de Man 1902) and A. telestophila (Johnson 1958), and the species described by Nakasone and Miyake (1969), A. kikuchii. A fifth species, A. taiwanensis, was subsequently described by Dong et al. (2011). Here we describe a new sponge-dwelling species of Aliaporcellana from material collected in the Philippines and Indonesia. Despite having been frequently photographed by divers because of its striking coloration and relatively large size, the species has not been described. With the exception of A. telestophila , commensalism has never been reported for other congeners. We highlight the characters distinguishing the new species from its congeners, and discuss the morphological traits, present in all Aliaporcellana species and other porcellanids associated with sponges, which we interpret as adaptations to living on these hosts. Material and methods We found the new species in material collected in the Philippines by G. Paulay [Florida Museum of Natural History, Gainesville, U.S.A. (UF)] and in Indonesia by C.H.J.M. Fransen [Naturalis Leiden, The Netherlands (RMNH)]. The holotype is deposited in the National Museum of Natural History, Philippines (NMCR). Color photographs of the holotype and of the live crab in the field were provided by G. Paulay, and were included in the description. Measurements of carapace length and width (in mm) of type individuals follow collection information. Results Systematic account Family Porcellanidae Aliaporcellana spongicola sp. n. http://zoobank.org/21BCF647-FA9C-43C6-B604-5FCBD474643D Figures 1–5 Material. Holotype: female (ovigerous), NMCR 4966, ex UF 43328, Philippines, Oriental Mindoro Province, Mindoro, Puerto Galera, off Pt W of Bayanar Beach, 13.5118°N 120.9088°E, 10–13 m, sand slope, coll. G. Paulay, 02.04.2015, 6.8 × 7.0 mm. Paratypes: 2 females (ovigerous), UF 43328, same collection data as holotype, 7.4 × 7.6 mm, 5.2 × 5.2 mm;1 female (ovigerous), UF 42943, Philippines, Oriental Mindoro Province, Mindoro, Puerto Galera, Batangas Channel, 13.5199°N 120.9604°E, On a new commensal species of Aliaporcellana from the western Pacific... 3 Figure 1. Aliaporcellana spongicola sp. n. Female (ovigerous) paratype, UF 43328 (Photo UF dPHIL 7104), Philippines, Oriental Mindoro Province, Mindoro, Puerto Galera, off Pt W of Bayanar Beach. Scale bar: 3.5 mm. 11 m, lagoon sand slope with sponge, coll. G. Paulay, 12.04.2015, 6.2 × 6.8mm; 2 males, 1 female (ovigerous), RMNH.CRUS.D.57287, Indonesia, SW Sulawesi, Spermonde Archipelago, Bitung, sta. 17, 20 m, from large grey folious sponge, cleaning station, coll. C.H.J.M. Fransen, 30.10.1994, 4.8 × 4.4 mm, 3.3 × 3.0 mm, 5.2 × 4.8 mm. Description. Carapace rounded (Figures 1, 2), considerably variable in form and in length-width ratio; larger females with carapace broader than long (ratio < 1), smaller individuals with carapace relatively longer than broad (ratio > 1); dorsal surface convex, glossy, with faint, transverse striae on branchial and intestinal regions; cervical grooves gently depressed. Front (Figures 1, 2) broad, slightly produced beyond eyes, weakly trilobate, somewhat deflexed; frontal lobe visible in dorsal view, grooved, overreaching lateral ones. Distal margin of entire front lined with row of rounded, upwardly directed small spines (Figure 3a), the largest on supraocular edges. Outer orbital angles (Figure 2) forming acute, bifid tooth followed by hepatic spine of similar size. Epibranchial margin rounded, produced outwards, marked with epibranchial spine; cervical groove faintly marked. Mesial branchial margins crested, with row of 5 or 6 strong, anteriorly, upwardly directed spines of increasing size posteriorly. Sidewalls entire. Eyes moderately large (Figures 1, 2, 3a), retracted, ocular peduncles short. First movable segment of antennal peduncle (Figures 2, 3b) with strong, anteriorly curved distal spine, second with smaller, anterodistal, acute protuberance, third one globular. Basal segment of antennular peduncle (Figure 3c) with anterior surface transversely 4 (...truncated)