Bull Mar Sci. 90(3):865–872. 2014 new taxa paper http://dx.doi.org/10.5343/bms.2013.1079
A new mangrove-inhabiting porcelain crab of the genus Enosteoides (Crustacea: Decapoda: Anomura) from Puerto Princesa Bay, Palawan, the Philippines
1 * 1 College of Fisheries and Aquatic Roger G Dolorosa Sciences, Western Philippines Bernd Werding 2 University-Puerto Princesa Campus, Palawan, Republic of the Philippines. 2 Department of Animal Ecology, Abstract.—A mangrove-inhabiting porcelain crab, Justus-Liebig University, Enosteoides philippinensis sp. nov., is described based on Giessen, Germany. material collected from Palawan Island, the Philippines. It is the fifth species of the genus and different from its congeners * Corresponding author email:
Enosteoides was first established by Johnson (1970) as a subgenus of Porcellana Lamarck, 1801 and later raised to a generic rank by Haig (1978). The genus currently contains four Indo-West Pacific species: Enosteoides ornatus (Stimpson, 1858), Enosteoides melissa (Miyake, 1942), Enosteoides palauensis (Nakasone and Miyake, 1968), and Enosteoides lobatus Osawa, 2009. During study by the first author on the biology of mangrove-inhabiting porcelain crabs in Puerto Princesa Bay, Palawan, the Philippines, an unusual species of porce- lain crab was encountered. Detailed examination of the specimens revealed that it is an undescribed species of the genus Enosteoides. The present study describes the new species as the fifth in the genus.
Methods
Porcelain crabs were collected in a mangrove forest in the city of Puerto Princesa between January 2003 and June 2004. Microhabitats such as undersides of stones, spaces between mangrove roots, decaying mangrove trunks, and sponges were care- fully searched for the crabs. To minimize habitat disturbance, traps made of bundles of firewood were set among mangrove roots and were retrieved after two months. At the first retrieval of traps, two unidentified porcelain crabs were collected. Subsequent continuous trapping resulted in the capture of 19 additional individuals. Collected specimens were preserved in 95% ethanol and stored in a refrigerator until further examination. The carapace length (cl) and carapace width (cw) were measured with Vernier calipers to the nearest 0.1 mm. The holotype and one paratype are deposited at Forschungsinstitut und Naturmuseum Senckenberg, Frankfurt am Main (SMF),
Bulletin of Marine Science 865 © 2014 Rosenstiel School of Marine & Atmospheric Science of the University of Miami 866 Bulletin of Marine Science. Vol 90, No 3. 2014
Germany, and other paratypes are kept in the Western Philippines University-Puerto Princesa Campus (WPU-PPC).
Results
Family Porcellanidae Haworth, 1825 Genus Enosteoides Johnson, 1970 Enosteoides philippinensis new species urn:lsid:zoobank.org:act:08967713-C134-4125-BCDB-AF90398D462B (Figs. 1–5)
Material Examined.—Holotype.—♀, Puerto Princesa, Palawan, the Philippines, mangrove forest, intertidal, 9°46.886´N and 118°43.365´E, coll. R Dolorosa, 14 June, 2004, SMF 45447. Paratypes.—1♂, same data as holotype, SMF 45448; 1♂, same data as holotype, 7 August, 2003, WPU-PPC 1.01; 1♂, same data as holotype, 14 June, 2004, WPU-PPC 1.02; 1♀, parasitized with bopyrid, same data as holotype, 7 August, 2003, WPU-PPC 1.03; 1♀, parasitized with bopyrid, same data as holotype, 14 June, 2004, WPU-PPC 1.04; 6♀♀, parasitized with bopyrids, same data as holotype, 14 June, 2004, WPU- PPC 1.05–1.10. Measurements.—Largest male cl 9.3 mm, cw 8.3 mm; largest female cl 10.0 mm, cw 9.5 mm. Description.—Carapace (Figs. 1, 2A, 4A) nearly as long as broad or slightly lon- ger than broad, dorsal surface convex, sparsely setose except posterior branchial regions; regions distinctly separated. Protogastric ridge bilobed, each with median cristate tubercle. Anterior branchial regions with some blunt spines or tubercles. Cardiac and gastric regions with sparse ridges. Epibranchial spines absent. Branchial margins convex anteriorly, bordered by an elevated crest, mesobranchial margins subparallel or slightly convex, with two strong spines. Rostrum (Fig. 2B) trilobate, median lobe broader and exceeding lateral lobes, anterior margin emarginated in dorsal view, with apex strongly bent downwards; lateral lobes rounded in dorsal view. Orbits shallow, outer orbital angle weakly produced. Lateral margins of carapace and pterygostomian region (Fig. 2A,D) densely setose. Thoracic sternum setose on surface. Third thoracic sternite (Fig.C 2 ) trilobate, median lobe very broad, anteriorly rounded; lateral lobes narrow, slightly exceeding median lobe. Forth thoracic sternite anteriorly with dense long setae, overreaching anterior margin of third thoracic sternite. Telson (Fig. 2E) seven-plated. Eyes (Figs. 1, 2A) small, peduncle hardly visible from dorsal view. Basal article of antennule (Fig. 2F) rounded with two lobes mesially on anterior margin. Chelipeds (Figs. 1, 2H, 4A,B) subequal, densely setose on dorsal surface but smooth on ventral surface. Carpus about twice as long as broad, with three blunt low teeth on proximal half of anterior margin; posterior margin with distal edge produced to a spine, followed by second one at one third of distance; dorsal surface Dolorosa and Werding: Enostenoides philippinensis from the Philippines 867
Figure 1. Enosteoides philippinensis sp. nov. Holotype. Female (cl 8.1 mm, cw 7.8 mm). SMF 45447. Entire animal, dorsal view. with longitudinal ridge along midline; outer margin of palm with 3 or 4 irregularly set spines at proximal half. Ambulatory legs (L1–L3) (Figs. 3, 4A, B) slender, decreasing in length posteriorly, first leg longest. Meri densely setose; anterior margin unarmed in L1, with vestigial blunt spine near distal end in L2 and L3. Carpi without spines. Propodi ventrally with triplet of movable distal spines, one additional subdistal spine in L2 and L3. Dactyli with 3 or 4 spinules on posterior margin. Variation.—The number of teeth on the anterior margin of the carpus of the cheli- ped ranges from two or three, the most proximal tooth is sometimes absent or blunt. The number of proximal spines on the outer margin of the palm ranges from one to five. The spines at the mesobranchial margins of carapace range from two to four. The granulation on the anterior margin of the basal antennular article is relatively more prominent in larger individuals. Color.—In life, the dorsal surfaces of the carapace and pereopods are pale pink to pale brown, thick setae are dark brown. In preservative, carapace generally light pink, reddish, or brownish mottled with white or pale pink. Etymology.—The new species is named after the Republic of the Philippines, the country where the type locality of E. philippinensis is situated. 868 Bulletin of Marine Science. Vol 90, No 3. 2014
Figure 2. Enosteoides philippinensis sp. nov. Paratype male (cl 5.5 mm, cw 5.5 mm) WPU-PPC 1.01. (A) carapace, dorsal view; (B) front, anterior view; (C) third thoracic sternite, ventral view; (D) left pterygostomian flap, lateral view; (E) telson, external view; (F) basal article of the right antennule, ventral view; (G) endopod of left third maxilliped; (H) right cheliped, dorsal view. Scale bars: 1 mm. Dolorosa and Werding: Enostenoides philippinensis from the Philippines 869
Figure 3. Enosteoides philippinensis sp. nov. Paratype male (cl 5.5 mm, cw 5.5 mm) WPU-PPC 1.01. Right ambulatory legs, lateral view, (A) first leg (L1); (B) second leg (L2); (C) third leg (L3). Scale bar: 1 mm.
Figure 4. Enosteoides philippinensis sp. nov. Holotype. Female (cl 8.1 mm, cw 7.8 mm). SMF 45447. (A) Entire animal, dorsal view; (B) entire animal, ventral view. Setae were cleaned and some setae were removed to reveal the surface features of the specimen. 870 Bulletin of Marine Science. Vol 90, No 3. 2014
Figure 5. The basal article of the antennules of Enosteoides spp. (A) Enosteoides ornatus; (B) Enosteoides palauensis; (C) Enosteoides melissa; (D) Enosteoides philippinensis; and (E) Enosteoides lobatus). Scale bars: 0.5 mm.
Ecology.—The new species inhabits the intertidal in the outer most part of man- grove forest with rocky or coral rubble substrate. Some individuals were collected together with Petrolisthes bifidus Werding and Hiller, 2004 and Petrolisthes teres Melin, 1939 in a bundle of wood, which was set among the prop roots of mangrove trees of the genus Rhizophora. Of the 19 previously available specimens (a number were damaged during the first author’s years of absence from the university), four (50%) of the eight males and six (54.55%) of the 11 females were infested with isopods.
Discussion
Some similarities and differences between Enosteoides philippinensis sp. nov. and its congeners are reflected in Table 1 (see Miyake 1943, Nakasone and Miyake 1968, Haig 1992, Hsieh et al. 1997, Osawa 2009): The percentage of parasitism of bopyrids on E. philippinensis sp. nov. is much high- er compared with other mangrove associated porcelain crabs such as P. teres (0.04 %), P. bifidus (2.53%), and Petrolisthes kranjiensis Johnson, 1970 (9.85%) (Dolorosa 2005). It remains uncertain whether or not the same species of parasite infests the four Dolorosa and Werding: Enostenoides philippinensis from the Philippines 871 Enosteoides philippinensis Hidden Longitudinal ridge 3 blunt spines proximally 1 spine on distal half 2 granulated lobes 2–4 1–5 spines 3 or 4 Enosteoides melissa Hidden 2 granulated ridges 2 broad obtuse teeth proximally Granulated crest Granulated 2 strong teeth 2 or 3 4 or 5 spines proximally 3 . Enosteoides palauensis Hidden 2 granulated ridges 2 or 3 minute teeth/ spinules 5 spinules 2 strong unequal teeth 2 Denticulated proximally 5 or 6 Enosteoides ornatus Enosteoides Visible 2 longitudinal ridges Minutely serrated, with with serrated, Minutely small denticulated lobe at the base Dentate With sharp spines With 2–6 Denticulated 5 or 6 Enosteoides lobatus Visible Longitudinal elevated crest 1–3 subtriangular1–3 teeth on proximal half With row of smallWith of row spines 2 granulated lobes 2–4 Denticulated 3 spines Body parts Table 1. Selected 1. similaritiesTable and differences among the species five of thegenus Enosteoides Eye stalkEye above) (from Carpus cheliped of surface) (dorsal Carpus cheliped of (anterior margin) Carpus cheliped of (posterior margin) Basal segment of antennules Number spines of on mesobranchial margin of carapace Outer margin chela of Number spines of on posterior margin of propodus walking of legs 872 Bulletin of Marine Science. Vol 90, No 3. 2014 species of porcelain crabs or what the reasons are for the variability of infestation for each species. The discovery of the new species in Puerto Princesa Bay may suggest the possible occurrence of more unrecorded or undescribed porcelain crabs within the mangrove forests and related marine habitats of Palawan.
Acknowledgments
The comments and suggestions of S Schoppe and of the three reviewers are greatly acknowledged. The Nagao Natural Environment Foundation, Tokyo, Japan, funded this study.
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