INTRODUCTION
Ascension Island is an isolated landmass in the central Atlantic Ocean, about 3000 km east of Brazil and 3000 km west of Africa, with the nearest neighbour being St Helena, about 1300 km to the south. The island has been visited by numerous early scientific expeditions, with the first decapod, Grapsus adscensionis (Osbeck, 1765) being recorded by Linnaeus (Reference Linnaeus1754, as Cancer retusus Linnaeus, Reference Linnaeus1754). Over the ensuing decades, knowledge of the decapod fauna accumulated piecemeal, but was considerably enhanced by incidental collections sent to the late Ray Manning (United States National Museum, Smithsonian Institution, Washington DC) in 1970, which not only led to the description of two endemic taxa (see Chace & Manning, Reference Chace and Manning1972), but also resulted in two expeditions to the island by him and colleagues in 1971 and 1976. Accumulated knowledge of the decapod fauna of the island based on all collected material up to 1985 was summarized in the monograph of Manning & Chace (Reference Manning and Chace1990). Since then, only two additional species have been recorded, Alpheus cedrici Anker & De Grave, Reference Anker and De Grave2012 and Typton holthuisi De Grave, Reference De Grave, Fransen, De Grave and Ng2010 based on the 2008 Oxford University Museum of Natural History (OUMNH) expedition to the island. The present contribution reports on the other decapod species collected during the OUMNH 2008 expedition as well as further taxa collected during a 2012 expedition led by P. Brickle (Shallow Marine Surveys Group). Additionally, a number of specimens donated to OUMNH over the years are reported upon, as is a small, but significant, collection by P. Wirtz during 2014. Some of the material resulting from the 2008 expedition has already been reported upon (De Grave, Reference De Grave, Fransen, De Grave and Ng2010; Anker & De Grave, Reference Anker and De Grave2012) and is not further treated. All material examined is deposited in OUMNH, the Natural History Museum, London (NHMUK), Naturhistorisches Museum, Vienna (NHMW) or the Lee Kong Chian Natural History Museum (ex. Raffles Museum of Biodiversity Research), National University of Singapore (ZRC).
Much of the intertidal and subtidal coastline on Ascension is inaccessible, consequently the majority of collections were made at only a limited number of locations (Figure 1) with their geographical coordinates listed in Table 1.
Under each species treated, only the first record is listed for Ascension, fuller synonymies can be found in Manning & Chace (Reference Manning and Chace1990). An update of the known marine decapod fauna of the island is provided (Table 2), extending the species list in Manning & Chace (Reference Manning and Chace1990), with up to date nomenclature.
Size measurements: Size of carideans and stenopodideans was measured between the post-orbital margin and the posterior end of the carapace, along the dorsal line (pocl) for non-alpheids or including the rostrum (cl) for alpheids; brachyurans as carapace width (cw); paguroids as shield length (sl); callianassids as total length (tl) and carapace length (cl); and hippids as carapace length (cl); all measurements being in mm.
Abbreviations: female (♀); male (♂); ovigerous (ov.); juvenile (juv.); individual (ind.); including (incl.) and field collection numbers (fcn), the latter only given when known.
RESULTS
Order DECAPODA Latreille, 1802
Infraorder STENOPODIDEA Spence Bate, 1888
Family STENOPODIDEA Claus, 1872
Odontozona anaphorae Manning & Chace, Reference Manning and Chace1990
(Figure 2A, B)
Manning & Chace, Reference Manning and Chace1990, p. 29; figures 14–15
MATERIAL EXAMINED
fcn C41/003, 2 ov.♀, pocl, 4.6, 4.7, 1♂, pocl 4.5, western side of English Bay, in lava tube, 13 m, 4 September 2012, OUMNH.ZC.2014.03.01/02/03.
REMARKS
This endemic species to Ascension was previously only known from the male holotype, collected in 1980 off North Point (Manning & Chace, Reference Manning and Chace1990). The present specimens demonstrate considerable variation in carapace and pereiopod spination, but are consistent with the diagnosis of the species. The previously unknown colour pattern is illustrated in Figure 2A, B.
MATERIAL EXAMINED
fcn ASC-009/010, 1♂, pocl 6.5, 1♀, pocl 7.3, west side of English Bay, hand collecting under ledge, 10 m, 10 April 2008, OUMNH.ZC.2008.11.82/83.
Infraorder CARIDEA Dana, 1852
Family ALPHEIDAE Rafinesque, 1815
Alpheus bouvieri A. Milne Edwards, 1878
Manning & Chace, Reference Manning and Chace1990, p. 14.
MATERIAL EXAMINED
fcn ASC-013/014, 1 ov.♀, pocl 10.0, 1♀, pocl 4.7, east side of English Bay, in outfall stream of desalination plant, intertidal, 10 April 2008, OUMNH.ZC.2008.11.024/028; fcn ASC-068, 1♀, pocl 3.6, English Bay, North Point, in rock pools, intertidal, 14 April 2008, OUMNH.ZC.2008.11.009; 2 juv., same location, 17 April 2008, OUMNH.ZC.2008.11.0008; fcn ASC-098, 7 ind., incl. ov.♀, pocl 3.0–4.0, Shelly Beach, intertidal pools, 16 April 2008, OUMNH.ZC.2008.11.025/055; 1♀, pocl 5.5, Turtle Beach Point, from algal clumps, intertidal, 11 April 2008, OUMNH.ZC.2008.11.054; 3 juv., Collyer Point, by blowhole, intertidal, 15 April 2008, OUMNH.ZC.2008.11.059.
Alpheus cedrici Anker & De Grave, Reference Anker and De Grave2012
Anker & De Grave, Reference Anker and De Grave2012, p. 2; figures 1–3.
MATERIAL EXAMINED
fcn C37/006, 1♀, cl 6.0, Mars Bay, 15.1 m, 2 September 2012, OUMNH.ZC.2014.03.012; fcn SP3/002, 1♀, cl 10.3, off Wigan Pier, on settlement panel, 12.4 m, 4 September 2012, OUMNH.2014.03.014.
REMARKS
This recently described species (Anker & De Grave, Reference Anker and De Grave2012) was previously only known from the type series collected in English Bay. The additional records herein indicate the species to be more widespread around the island.
Alpheus crockeri (Armstrong, 1941)
Manning & Chace, Reference Manning and Chace1990, p. 14.
MATERIAL EXAMINED
fcn C45/001,1♂, pocl 5.8, 1 ov.♀, pocl 5.2, Wigan Pier, 12.4 m, 5 September 2012, OUMNH.ZC.2014.03.013; fcn C36/011, 1♂, pocl 6.8, 2♀, pocl 4.5, 5.0, Wigan Pier, 13.4 m, 2 September 2012, OUMNH.ZC.2014.03.016.
REMARKS
The present specimens conform to the description of the eastern Atlantic material reported under this name by Crosnier & Forest (Reference Crosnier and Forest1966) and differ from the western Atlantic A. hortensis Wicksten & McClure, Reference Wicksten and McClure2003, in possessing a conspicuous dorso-distal tooth on the palm of the minor cheliped overhanging the base of the fingers, which is lacking in A. hortensis. Wicksten & McClure (Reference Wicksten and McClure2003) did, however, express considerable doubt as to whether the eastern Atlantic populations reported under this name are identical to this widespread Indo-West Pacific species.
Alpheus dentipes Guérin, 1832
Manning & Chace, Reference Manning and Chace1990, p. 15.
MATERIAL EXAMINED
1 juv., Comfortless Cove, from Sabellaria reef, 1 m, 10 April 2008, OUMNH.ZC.2008.11.036; 4 ind., incl. ov.♀, cl 2.3–5.4, same location, in coralline algal concretions, 2 m, 13 April 2008, OUMNH.ZC.2008.11.015/029/037/046; 1 juv., same location, inside maerl balls, 2 m, 12 April 2008, OUMNH.ZC.2008.11.056; 3♀, cl 2.2–4.2, same location, underneath sponge, 5 m, 14 April 2008, OUMNH.2008.11.044; 10 ind., incl. ov.♀, cl. 2.5–6.5, same location, from maerl ball, 5 m, 14 April 2008, OUMNH.ZC.2008.11.020; 12 ind., incl. ov.♀, cl 2.0–4.5, McArthur Point, from algal clumps, intertidal, 12 April 2008, OUMNH.ZC.2008.11.019/039/045/047; fcn ASC-122,1♀, cl 4.8, east of McArthur Point, from coralline algae, intertidal pools, 17 April 2008, OUMNH.ZC.2008.11.038; fcn ASC-090, 2 juv., Collyer Point, by blowhole, intertidal, 15 April 2008, OUMNH.ZC.2008.11.058; 1 juv., English Bay, north point, in intertidal rock pools, 14 April 2008, OUMNH.ZC.2008.11.021; fcn C10/005, 1 ov.♀, cl 5.0, Red Rock, 23 August 2012, OUMNH.ZC.2014.03.017.
Alpheus holthuisi Ribeiro, 1964
Manning & Chace, Reference Manning and Chace1990, p. 15.
MATERIAL EXAMINED
fcn ASC-152, 1 ov.♀, cl 5.0, western side of English Bay, under rocks, 15 m, 17 April 2008, OUMNH.ZC.2008.11.012; 1♂, cl 3.0, Collyer Point, by blowhole, intertidal, 15 April 2008, OUMNH.ZC.2008.11.060.
Alpheus paracrinitus Miers, Reference Miers1881
Ortmann, Reference Ortmann1893, p. 45 (as Alpheus ascensionis)
Manning & Chace, Reference Manning and Chace1990, p. 16.
MATERIAL EXAMINED
fcn ASC-032-043, 12 ind., cl 3.2–4.5, Comfortless Cove, in coralline algal concretions, 2 m, 13 April 2008, OUMNH.ZC.2008.11.003/004/013/023/032/051; 1 juv., same location, from Sabellaria reef, 1 m, 10 April 2008, OUMNH.ZC.2008.11.033; 1♂, cl 3.2, same location, inside maerl balls, 2 m, 12 April 2008, OUMNH.ZC.2008.11.027; 1 ov.♀, cl 6.3, western side of English Bay, under rocks, 10 m, 17 April 2008, OUMNH.ZC.2008.11.050; fcn ASC-151,1♀, cl 5.7, same location, under rocks, 15 m, OUMNH.ZC.2008.11.049; 1♂, cl 4.0, English Bay, North Point, in intertidal rock pools, 14 April 2008, OUMNH.ZC.2008.11.022.
REMARKS
This species was first recorded from Ascension Island by Ortmann (Reference Ortmann1893) as Alpheus ascensionis Ortmann, Reference Ortmann1893. Holthuis (Reference Holthuis1951) placed A. ascensionis into the synonymy of A. paracrinitus, therein followed by Crosnier & Forest (Reference Crosnier and Forest1966). Although a species complex is involved, it seems likely that the Ascension population belongs to A. paracrinitus sensu stricto in view of the proximity to the type locality (Senegal).
Automate dolichognatha De Man, 1888
Manning & Chace, Reference Manning and Chace1990, p. 16.
MATERIAL EXAMINED
fcn ASC-158,1 ov.♀, cl 4.2, western side of English Bay, under rocks, 10 m, 17 April 2008, OUMNH.ZC.2008.11.002/011; fcn ASC-136, 137,1 ov ♀, cl 4.1, 2♀, cl 3.7, 4.7, same location, 16 April 2008, OUMNH.ZC.2008.11.001/010/030.
REMARKS
Although the material is herein assigned to A. dolichognatha, it is however acknowledged that the true status of the central and also western Atlantic populations must await a full revision of what is undoubtedly a pantropical species complex.
Metalpheus paragracilis (Coutière, 1897)
Manning & Chace, Reference Manning and Chace1990, p. 16.
MATERIAL EXAMINED
1♂, cl 2.7, Comfortless Cove, underneath sponge, 5 m, 14 April 2008, OUMNH.ZC.2008.11.043; fcn ASC-029, 1♂, cl 2.7, 1 ov.♀, cl 4.5, McArthur Point, from intertidal algal clumps, 12 April 2008, OUMNH.ZC.2008.11.40/42; fcn ASC-139, 1 ov.♀, cl 4.0, English Bay, North Point, from intertidal rockpool, 16 April 2008, OUMNH.ZC.2008.11.041; fcn ASC-148, 1 ov.♀, cl 4.5, western side of English Bay, under rocks, 15 m, 17 April 2008, OUMNH.ZC.2008.11.026; fcn C19/004, 1♀, cl 4.7, 1 juv., The Arches, 22 m, 25 August 2012, OUMNH.ZC.2014.03.015.
Metalpheus rostratipes (Pocock, 1890)
Manning & Chace, Reference Manning and Chace1990, p. 16.
MATERIAL EXAMINED
1 ov.♀, cl 4.8, McArthur Point, from intertidal algal clumps, 12 April 2008, OUMNH.ZC.2008.11.048; fcn ASC-120, 128, 5 ind., incl. ov.♀, cl 2.0–3.2, east of McArthur Point, from coralline algae wash, intertidal pool, 17 April 2008, OUMNH.ZC.2008.11.005/006; fcn ASC-006, 1 ov.♀, cl 4.0, Comfortless Cove, from Sabellaria clump, 1 m, 10 April 2008, OUMNH.ZC.2008.11.034; 2 juv., Turtle Beach Point, from intertidal algal clumps, 11 April 2008, OUMNH.ZC.2008.11.052/053.
Parabetaeus hummelincki (Schmitt, 1936)
Manning & Chace, Reference Manning and Chace1990, p. 17 (as Neoalpheopsis euryone)
MATERIAL EXAMINED
1♀, cl 5.5, western side of English Bay, under rocks, 15 m, 17 April 2008, OUMNH.ZC.2008.11.031.
REMARKS
This species was first recorded from Ascension Island by Manning & Chace (Reference Manning and Chace1990) as Neoalpheopsis euryone, following Banner & Banner (Reference Banner and Banner1985) who considered there to be only a single, pantropical species. Following the synonymization of Neoalpheopsis Banner, 1953 with Parabetaeus Coutière, 1896 in Nomura & Anker (Reference Nomura and Anker2001), the Atlantic species was tentatively resurrected (as P. hummelincki) by Anker (Reference Anker2007).
Salmoneus setosus Manning & Chace, Reference Manning and Chace1990
Manning & Chace, Reference Manning and Chace1990, p. 17
MATERIAL EXAMINED
fcn ASC-028, 1 ov.♀, cl 3.0, McArthur Point, from algal clumps, intertidal, 12 April 2008, OUMNH.ZC.2008.11.007; fcn ASC-053/056, 1 ov.♀, cl 3.0, 1 juv., Comfortless Cove, in coralline algal concretions, 2 m, 13 April 2008, OUMNH.ZC.2008.11.016/073.
REMARKS
Although originally described from Ascension Island, the species is now also known from Atol das Rocas and Fernando de Noronha, Brazil (Anker, Reference Anker2007), as well as the Yucatan Peninsula, Mexico (Anker, Reference Anker, De Grave and Fransen2010),
Synalpheus fritzmuelleri Coutière, 1909
Manning & Chace, Reference Manning and Chace1990, p. 22
MATERIAL EXAMINED
1 ov.♀, cl 3.5, Comfortless Cove, in coralline algal concretions, 2 m, 13 April 2008, OUMNH.ZC.2008.11.014; 1 ov.♀, cl 3.4, same location, from Sabellaria clumps, 1 m, 10 April 2008, OUMNH.ZC.2008.11.035.
Family GNATHOPHYLLIDAE Dana, 1852
Gnathophyllum americanum Guérin-Méneville, 1855
MATERIAL EXAMINED
1 juv., pocl 1.2, English Bay, 12 m, under stone, leg. P. Wirtz & P. Nahke, 6 February 2014, OUMNH.ZC.2014.01.020.
REMARKS
A further individual of this distinctly coloured species was also observed by PW when turning over a stone in 13 m depth in English Bay on 10 September 2012. The animal escaped before it could be photographed or collected. These constitute the first record of this pantropical species for Ascension Island and the central Atlantic.
Gnathophyllum ascensione Manning & Chace, Reference Manning and Chace1990
Manning & Chace, Reference Manning and Chace1990, p. 11.
MATERIAL EXAMINED
fcn ASC-119, 1♀, pocl 1.5, east of MacArthur Point, intertidal pool, under Diadema ascensionis, 17 April 2008, OUMNH.ZC.2008.11.075.
REMARKS
The specimen had a uniform black colour. The type series was found associated with Echinometra lucunter polypora, the present specimen constituting a new host record.
Family HIPPOLYTIDAE Spence Bate, 1888
Lysmata grabhami (Gordon, 1935)
Manning & Chace, Reference Manning and Chace1990, p. 23.
MATERIAL EXAMINED
2 ind., pocl 8.0, 9.4, Porpoise Point, under rocks, 14 m, 19 June 2010, leg. RAF diving team, OUMNH.ZC.2010.04.028/029; fcn C32/004, 2 ind., pocl 10.0–11.0, Stack in South-East Bay, 25 m, 1 September 2012, OUMNH.ZC.2014.03.018.
Lysmata moorei (Rathbun, 1901)
Chace, Reference Chace1972, p. 128; Manning & Chace, Reference Manning and Chace1990, p. 23
MATERIAL EXAMINED
fcn ASC-96-111, 25 ind., pocl 2.1–3.5, Shelly Beach, in intertidal pools, 16 April 2008, OUMNH.ZC.2008.11.063/064/065/066/096/097/098/099/100; 1 ind., pocl 3.9, Red Rock, 15 m, from crack in rock, leg. P. Wirtz & P. Nahke, 9 February 2014, OUMNH.ZC.2014.01.021.
Thor manningi Chace, Reference Chace1972
Manning & Chace, Reference Manning and Chace1990, p. 24
MATERIAL EXAMINED
fcn Q27/003, 1 ov.♀, pocl 1.5, Comfortless Cove, 10 m, 28 August 2012, OUMNH.ZC.2014.03.010; 1 ov.♀, pocl 1.7, 1 ind., English Bay, 10 m, in crack in rock, leg. P. Wirtz & P. Nahke, 9 February 2014, OUMNH.ZC.2014.01.018.
REMARKS
One of the individuals is noteworthy by possessing an acute branchiostegal tooth on the right-hand side of the carapace, with all other morphological features, as well as the colour pattern (photo by PW), fitting the diagnosis of T. manningi.
Family PALAEMONIDAE Rafinesque, 1815
Brachycarpus biunguiculatus (Lucas, 1846)
Manning & Chace, Reference Manning and Chace1990, p. 9.
MATERIAL EXAMINED
fcn ASC-116, 1♂, pocl 4.5, western side of English Bay, under rocks, 5–10 m, 16 April 2008, OUMNH.ZC.2008.11.076; fcn ASC-147, 1♂, pocl 6.2, same location, under rocks, 15 m, 17 April 2008, OUMNH.ZC.2008.11.085; fcn C32/006, 1♀, pocl 4.7, Stack in South-East Bay, 25 m, 1 September 2012, OUMNH.ZC.2014.03.05; fcn C36/009, 1♂, pocl 3.5, 1♀, pocl 4.4, Wigan Pier, 13.4 m, 2 September 2012, OUMNH.ZC.2014.03.09; fcn C45/012, 1 ind., Wigan Pier, 12.4 m, 5 September 2012, OUMNH.ZC.2014.03.07; 1♂, bopyrised, pocl 4.5, Red Rock, 15 m, from crack in rock, leg. P. Wirtz & P. Nahke, 9 February 2014, OUMNH.ZC.2014.01.019.
Pontonia pinnophylax (Otto, 1821)
Manning & Chace, Reference Manning and Chace1990, p. 10.
MATERIAL EXAMINED
fcn ASC-011-012, 2♂, pocl 6.8, 7.8, 1 ov.♀, pocl 8.5, W side of English Bay, from Pinna rudis, 10 m, 10 April 2008, OUMNH.ZC.2008.11.078/081; fcn ASC-142-143, 1♂, pocl 9.0, 1♀, pocl 11.2, same location, from Pinna rudis, 15 m, OUMNH.ZC.2008.11.079/080; fcn C2/003, 1♀, pocl 10.5, Wigan Pier, 12 m, 19 August 2012, OUMNH.ZC.2014.03.04; fcn C2/008, 1♂, pocl 9.1, Wigan Pier, 12 m, 19 August 2012, OUMNH.ZC.2014.03.06.
Family PROCESSIDAE Ortmann, 1896
Processa packeri Manning & Chace, Reference Manning and Chace1990
Manning & Chace, Reference Manning and Chace1990, p. 24.
MATERIAL EXAMINED
fcn ASC-037-038, 13 ind., incl ov.♀, pocl 1.9–3.2, Comfortless Cove, inside maerl balls, 2 m, 12 April 2008, OUMNH.ZC.2008.11.057/069/089; 1♂, pocl 1.6, 1 ov.♀, pocl 1.1, same location, inside maerl balls, 5 m, 14 April 2008, OUMNH.ZC.2008.11.070/088; 3 ind., pocl 1.0–1.1, same location, in coralline algal concretions, 2 m, 13 April 2008, OUMNH.ZC.2008.11.090.
REMARKS
This species is the smallest processid shrimp worldwide, with females being ovigerous at 1.0–1.1 mm pocl.
Family RHYNCHOCINETIDAE Ortmann, 1890
Cinetorhynchus rigens (Gordon, 1936)
Manning & Chace, Reference Manning and Chace1990, p. 9 (as Rhynchocinetes rigens)
MATERIAL EXAMINED
fcn C41/002, 1♀, pocl 5.4, western side of English Bay, in lava tube, 13 m, 4 September 2012, OUMNH.ZC.2014.03.08.
Infraorder AXIIDEA de Saint Laurent, 1979
Family AXIIDAE Huxley, 1879
Axiopsis serratifrons (A. Milne-Edwards, 1873)
Manning & Chace, Reference Manning and Chace1990, p. 31; figures 16–17.
MATERIAL EXAMINED
1 juv., western side of English Bay, under rocks, 15 m, 17 April 2008, OUMNH.ZC.2008.11.093.
Family CALLIANASSIDAE Dana, 1852
Corallianassa longiventris (A. Milne-Edwards, 1870)
MATERIAL EXAMINED
fcn C45/024, 1♀, tl 71 cl 16.4, Wigan Pier, 12.4 m, 5 September 2012, NHMW 25601; fcn C50/004, 1 ind. (incomplete, cephalothorax posterior to P3, pleon missing), same location, 12 m, 7 September 2012, NHMW 25602.
REMARKS
Differences between C. longiventris and C. hartmeyeri have been outlined by Schmitt (Reference Schmitt1935) and Manning (Reference Manning1988). The present specimens show all characters typical for C. longiventris. While Sakai (Reference Sakai1999, Reference Sakai2005) considered both species valid (as Glypturus), Sakai (Reference Sakai2011) synonymized hartmeyeri with longiventris without presenting any arguments for his action. Recent examination of many specimens from Florida, the Gulf of Mexico and Yucatan, however, have shown that both species differ from each other by several characters (D.L. Felder, personal communication, April 2014). The species is herein newly recorded for Ascension Island.
Infraorder ASTACIDEA Latreille, 1802
Family ENOPLOMETOPIDAE de Saint Laurent, 1988
Enoplometopus antillensis Lütken, 1865
Manning & Chace, Reference Manning and Chace1990, p. 31.
MATERIAL EXAMINED
1♀, cl 20.5, Porpoise Point, under rocks, 14 m, 09/2010, leg. RAF diving team, OUMNH.ZC.2010.04.030.
REMARKS
A moult of this species was also found at English Bay on 9 September 2012, but not deposited.
Infraorder ANOMURA MacLeay, 1838
Family DIOGENIDAE Ortmann, 1892
Dardanus imperator (Miers, Reference Miers1881)
(Figure 2C)
Ortmann, Reference Ortmann1893, p. 52.
MATERIAL EXAMINED
fcn C29/003, 1 ind., sl 4.8, Catherine Point, 10 m, 30 August 2012, OUMNH.ZC.2014.03.019; fcn Q27/004, 2. ind., Comfortless Cove, 10 m, 28 August 2012, OUMNH.ZC.2014.03.020; fcn C10/002, 1 ind., sl 8.0, Red Rock, 23 August 2012, OUMNH.ZC.2014.03.021.
Family HIPPIDAE Latreille, 1825
Hippa testudinaria (Herbst, 1791)
Manning & Chace, Reference Manning and Chace1990, p. 41, Fig. 23a.
MATERIAL EXAMINED
fcn ASC 017, 4♂, cl 10.4–13.3, 1♀ 13.4, 1 ov.♀15.7, hand collecting, surf zone, Turtle Beach, 11 April 2008, OUMNH.ZC.2008.11.0094; fcn IT7/001, 4 ov.♀, cl 13.5–14.1, English Bay beach, 22 August 2012, NHMUK 2014.838-840.
Infraorder BRACHYURA Linnaeus, 1758
Family ACIDOPSIDAE Števčić, 2005
Acidops cessaci (A. Milne Edwards, 1878)
Manning & Chace, Reference Manning and Chace1990, p. 52.
MATERIAL EXAMINED
fcn ASC-155, 1♀, cw 17.3, 15 m, west side of English Bay, 17 April 2008, NHMUK 2014.561; fcn C11/008, 1♀, cw 16.2, 9 m, Darby Wreck arch, 23 August 2012, NHMUK 2014.841; fcn C18/004, 1♂, cw 12.9, 8.7 m, Darby Beach, 25 August 2012, not registered; fcn C50/005, 1 ov.♀, cw 16.4, 12 m, Wigan Pier, 7 September 2012, NHMUK 2014.842.
Family CALAPPIDAE De Haan, 1833
Calappa galloides Stimpson, 1859
Manning & Chace, Reference Manning and Chace1990, p. 45, Fig. 24a.
MATERIAL EXAMINED
fcn C50/007, 1♂, cw 17.6, 12 m, Wigan Pier, 7 September 2012, not registered.
Family CRYPTOCHIRIDAE Paulson, 1875
Troglocarcinus corallicola Verrill, 1908
Manning & Chace, Reference Manning and Chace1990, p. 69.
MATERIAL EXAMINED
fcn ASC-045, 1♂, cw 1.8, 2 ov.♀, cw 3.5, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.562-564.
Family EPIALTIDAE MacLeay, 1838
Acanthonyx sanctaehelenae (Chace, Reference Chace1966)
Manning & Chace, Reference Manning and Chace1990, p. 47.
MATERIAL EXAMINED
fcn ASC-008, 1♂, cw 2.3, from Sabellaria Reef, 1 m, Comfortless Cove, 10 April 2008, NHMUK 2014.759; fcn ASC-033, 1 juv., cw 2.0, hand collecting, intertidal, from algal clumps, McArthur Point, 12 April 2008, NHMUK 2014.562-564; fcn ASC-066, 1♀, cw 2.0, intertidal, in rock pools, English Bay, North Point, 14 April 2008, NHMUK 2014.770; fcn ASC-123, 1♂, cw 2.9, from coralline algae, intertidal pools, east of McArthur Point/Turtle Beach, 17 April 2008, NHMUK 2014.771.
Apiomithrax violacens (A. Milne-Edwards, 1868)
Manning & Chace, Reference Manning and Chace1990, p. 47.
MATERIAL EXAMINED
fcn C25/007, 1♂, cw 23.2, Comfortless Cove, 29 August 2012, not registered; fcn C46 003, 1♂, cw 8.7, English Bay, 5 September 2012, NHMUK 2014.843; fcn C55 002, 1 juv., 6.5, Two Hooks to English Bay, 9 September 2012, NHMUK 2014.844; fcn ASC-156 in rock pools, intertidal English Bay, North Point, 17 April 2008, OUMNH 2008-11-0077.
Family GRAPSIDAE MacLeay, 1838
Grapsus adscensionis (Osbeck, 1765)
Manning & Chace, Reference Manning and Chace1990, p. 63.
MATERIAL EXAMINED
fcn ASC-070, 3 juv., cw 7.2–9.1, on rocks by blowhole, intertidal, Collyer Point, 13 April 2008, NHMUK 2014.562-564; fcn ASC-071, 2 juv., cw 8.9, 11.8, on rocks by blowhole, intertidal, Collyer Point, 13 April 2008, NHMUK 2014.568-569; fcn ASC-076, 1 juv., diving, from maerl ball, 5 m, Comfortless Cove, 14 April 2008, NHMUK 2014.570; fcn ASC-084, 1 juv., cw 13.3, intertidal, Collyer Point, by blowhole, 15 April 2008, NHMUK 2014.571; fcn ASC-087, 1 juv., cw 9.5, intertidal, Collyer Point, by blowhole, 15 April 2008, NHMUK 2014.572; fcn ASC-089, 2 juv., cw 18.8, 20.8, intertidal, Collyer Point, by blowhole, 15 April 2008, NHMUK 2014.573-574; fcn ASC-118, 1 juv., cw 11.2, intertidal pools, east of McArthur Point/Turtle Beach, 17 April 2008, NHMUK 2014.575; 1 ov.♀, cw 55, 1♀, cw 58, 5♂, cw 44–64, in outlet of desalination plant, English Bay, intertidal, 10 April 2008, OUMNH.ZC.2008-11-061.
Pachygrapsus loveridgei Chace, Reference Chace1966
Manning & Chace, Reference Manning and Chace1990, p. 66.
MATERIAL EXAMINED
fcn ASC-003, 1♂, cw 4.2, 1 ov.♀, cw 4.7, from Sabellaria Reef, 1 m, Comfortless Cove, 10 April 2008, NHMUK 2014.576-577; fcn ASC-007, 1♂, cw 4.3, 1 ov.♀, cw 4.8, from Sabellaria reef, 1 m, Comfortless Cove, 10 April 2008, NHMUK 2014.578-579; fcn ASC-018, 1♂, cw 9.6, hand collecting, intertidal, from Sabellaria reef, Turtle Beach Point, 11 April 2008, NHMUK 2014.580; fcn ASC-019, 1♂, cw 5.8, 1 ov.♀, cw 8.9, hand collecting, intertidal, between oysters, Turtle Beach Point, 11 April 2008, NHMUK 2014.581-582; fcn ASC-036, 1♀, cw 6.0, hand collecting, intertidal, from algal clumps, McArthur Point, 12 April 2008, NHMUK 2014.583-584; fcn ASC-040, 1♀, cw 4.7, inside maerl balls, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.585; fcn ASC-081, 9♂, cw 4.3–5.7, 3♀, cw 4.0–4.5, intertidal, by blowhole, Collyer Point, 15 April 2008, NHMUK 2014.586-595; fcn ASC-082, 10♂, cw 3.6–7.3, 3♀, cw 6.0–4.1, intertidal, by blowhole, Collyer Point, 15 April 2008, NHMUK 2014.596-605; fcn ASC-093, 3 juvs, intertidal pools, Shelly Beach, 16 April 2008, NHMUK 2014.606-608.
Family PANOPEIDAE Ortmann, Reference Ortmann1893
Panopeus hartii Smith, 1869
Manning & Chace, Reference Manning and Chace1990, p. 57, figures 37, 38.
MATERIAL EXAMINED
fcn ASC-016, 1♀, cw 6.9, intertidal, rocky beach west of North East Bay, 11 April 2008, NHMUK 2014.772; fcn ASC-039, 2♂, cw 2.8, 3.0, 1 ov.♀, cw 4.0, inside maerl balls, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.773-775; fcn ASC-040, 1♀, cw 2.9, inside maerl balls, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.776; fcn ASC-069, 2♂, cw 6.0, 8.0, 2♀, cw 6.1, 8.1, intertidal, in rock pools, English Bay, North Point, 14 April 2008, NHMUK 2014.777-780; fcn ASC-083, 1♂, cw 4.2, intertidal, by blowhole, Collyer Point, 15 April 2008, NHMUK 2014.781; fcn ASC-095, 1♀, cw 10.8, intertidal pools, Shelly Beach, 16 April 2008, NHMUK 2014.781; fcn ASC-154, 2♂, cw 8.9, 10.1, in rock pools, intertidal, English Bay, North Point, 17 April 2008, NHMUK 2014.783-784; fcn C6/016, 1♂, cw 5.0, 9 m, Darby wreck, 21 August 2012, NHMUK 2014.845; fcn C19/005, 1♂, cw 6.5, 9.8 m, George Town Harbour, 27 August 2012, not registered; fcn C31/004, 1♂, cw 4.3, 1♀, cw 5.1, 12.8, Northeast Bay, 31 August 2012, NHMUK 2014.845; fcn C45/021, 1 ov.♀, cw 5.0, 12.4 m, Wigan Pier, 5 September 2012, NHMUK 2014.848.
Family PERCNIDAE Števčić, 2005
Percnon abbreviatum (Dana, 1851)
Manning & Chace, Reference Manning and Chace1990, p. 68, Fig. 44.
MATERIAL EXAMINED
fcn ASC-024, 1 juv., intertidal, from rocks, Turtle Beach Point, 11 April 2008, NHMUK 2014.783-784.
Percnon gibbesii (H. Milne Edwards, 1853)
Manning & Chace, Reference Manning and Chace1990, p. 68, Fig. 45.
MATERIAL EXAMINED
fcn ASC-144, 1♂, cw 15.6, diving, under Diadema, 15 m, west side of English Bay, 16 April 2008, NHMUK 2014.786; fcn C9/002, 1♂, cw 19.8, 4.6 m, Darby Beach, 22 August 2012, NHMUK 2014.849; fcn C18/006, 1♂, cw 15.1, 8.7 m, Darby Beach, 25 August 2012, not registered.
Family PORTUNIDAE Rafinesque, 1815
Laleonectes vocans (A. Milne-Edwards, 1878)
Manning & Chace, Reference Manning and Chace1990, p. 50, figures 32, 33.
MATERIAL EXAMINED
fcn C36/005, 1♀, cw 20.9, 13.4 m, Wigan Pier, 2 September 2012, not registered; fcn C47/002, 1 ov.♀, cw 28.0, 8 m, Darby Wreck, 9 June 2012, NHMUK 2014.850.
Portunus (Portunus) anceps (Saussure, 1858)
Manning & Chace, Reference Manning and Chace1990, p. 52, Fig. 34.
MATERIAL EXAMINED
fcn ASC-161, 1♂, cw 10.9, diving, 10 m, west side of English Bay, 17 April 2008, NHMUK 2014.787; fcn Q49/001, 1♀, cw 24.9, 8 m, Wigan Pier, 4 September 2012, NHMUK 2014.851.
Family PSEUDOZIIDAE Alcock, 1898
Euryozius sanguineus (Linnaeus, 1767)
(Figure 2D)
Manning & Chace, Reference Manning and Chace1990, p. 55, figure 36.
MATERIAL EXAMINED
fcn ASC-132, 1♂, cw 10.9, by hand, west side of English Bay, 10 m, 16 April 2008, NHMUK 2014.787; fcn 130405 Q5/B/01, 1♀ moult, cw 40.0, 16 m, Pyramid, 21 August 2012, NHMUK 2014.852; fcn Q17/001, 1♂, cw 18.9, 8.3 m, Long Beach, 24 August 2012, ZRC 2014.0342; fcn C38/003, 1♂, cw 12.3, 13.8 m, Pam Am Bay, 3 September 2012, NHMUK 2014. 854; fcn C40/003, 1♂ moult, cw 23.9, 9.3 m, Comfortless Cove, 4 September 2012, NHMUK 2014.855; fcn C47/001, 1 ov.♀, cw 35.5, 8 m, Darby Wreck, 6 September 2012, NHMUK 2014.856.
Family XANTHIDAE MacLeay, 1838
Cataleptodius olsoni Manning & Chace, Reference Manning and Chace1990
Manning & Chace, Reference Manning and Chace1990, p. 54, figure 35.
MATERIAL EXAMINED
fcn ASC-018, 1♀, cw 4.6, 1 ov.♀, cw 8.0, hand collecting, intertidal, from Sabellaria, Turtle Beach Point, 11 April 2008, NHMUK 2014.789-790; fcn ASC-019, 5♂, cw 3.6–6.9, 3♀, cw 4.9–7.3, hand collecting, intertidal, between oysters, Turtle Beach Point, 11 April 2008, NHMUK 2014.791-798; fcn ASC-021, 4♂, 3.6–5.3, 3♀, cw 3.8–4.3, hand collecting, intertidal, from algal clumps, Turtle Beach Point, 11 April 2008, NHMUK 2014.799-805; fcn ASC-024, 1♀ ov., cw 5.9, hand collecting, intertidal, from rocks, Turtle Beach Point, 11 April 2008, NHMUK 2014.806; fcn ASC-031, 1 ♀, cw 3.8, hand collecting, intertidal, from algal clumps, McArthur Point, 12 April 2008, NHMUK 2014.807; fcn ASC-035, 1 ov.♀, cw 7.2, hand collecting, intertidal, from algal clumps, McArthur Point, 12 April 2008, NHMUK 2014.808; fcn ASC-126, 1♂, cw 4.4, 1♀, cw 4.5, 1 ov.♀, 5.4, from coralline algae, intertidal pools, east of McArthur Point/Turtle Beach, 17 April 2008, NHMUK 2014.809-811; fcn ASC-127, 3♂, cw 3.4–5.3, 1♀, cw 3.8, from coralline algae, intertidal pools, east of McArthur Point/Turtle Beach, 17 April 2008, NHMUK 2014.812-815; fcn A2/001, 1♀, cw 4.8, no further details, not registered.
Microcassiope minor (Dana, 1852)
Manning & Chace, Reference Manning and Chace1990, p. 56.
MATERIAL EXAMINED
fcn C8/003, 1♂, cw 5.6, Darby Beach, 22 August 2012, NHMUK 2014.857; fcn C10/004, 1♂, cw 5.3, 1♀, cw 5.8, Red Rock, 23 August 2012, NHMUK 2014.858-859; fcn C35/003, 1♂, cw 4.6, 8.5 m, Northeast Bay, 31 August 2012, NHMUK 2014.860; fcn Q7/002, 1♀, cw 5.3, 16.8 m, Two Hooks, 22 August 2012, NHMUK 2014.861; 1♂, cw 5, 1 ov.♀, cw 7.9, 2012 no further details, not registered.
Nanocassiope melanodactylus (A. Milne Edwards, 1868)
Manning & Chace, Reference Manning and Chace1990, p. 57 (as Nannocassiope melanodactylus, erroneous spelling).
MATERIAL EXAMINED
fcn C45/018,1♂, cw 9.6, 12.4 m, Wigan Pier, 5 September 2012, not registered.
Paractaea rufopunctata africana Guinot, 1976
Manning & Chace, Reference Manning and Chace1990, p. 57, Fig. 39.
MATERIAL EXAMINED
fcn C09/001, 1♀, cw 13.1, 4.6 m, Darby Beach, 22 August 2012, NHMUK 2014.862; fcn C18 005, 1♂, cw 16.1, 8.7 m, Darby Beach, 25 August 2012, NHMUK 2014.863.
Platypodiella picta (A. Milne Edwards, 1899)
Manning & Chace, Reference Manning and Chace1990, p. 59.
MATERIAL EXAMINED
fcn IT18/002, 1 ov.♀, cw 16.3, west of English Bay, intertidal, 2 September 2012, NHMUK 2014.864; fcn C33/001, 1 ov.♀, cw 8.3, Boatswain Bird Island, 16 m, 1 September 2012, not registered.
Williamstimpsonia denticulatus (White, 1848)
Manning & Chace, Reference Manning and Chace1990, p. 60, figure 40 (as Xanthodius denticulatus).
MATERIAL EXAMINED
fcn ASC-001, 1♀, cw 11.0, from Sabellaria Reef, 1 m, Comfortless Cove, 10 April 2008, NHMUK 2014.816; fcn ASC-002, 3♂, cw 5.8–6.4, from Sabellaria Reef, 1 m, Comfortless Cove, 10 April 2008, NHMUK 2014.817-819; fcn ASC-032, 2 juvs, intertidal, from algal clumps, McArthur Point, 12 April 2008, NHMUK 2014.820-821; fcn ASC-039, 3 juvs, inside maerl balls, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.822-824; fcn ASC-061, 2♀, cw 6.0, 6.9, 3♂, cw 8.0–10.8, in coralline algal concretions, 2 m, Comfortless Cove, 13 April 2008, NHMUK 2014.825-829; fcn ASC-076, 1♀ cw 8.4, 1 juv., from maerl ball, 5 m, Comfortless Cove, 14 April 2008, NHMUK 2014.830-831; fcn ASC-079, 1♀, cw 14.0, intertidal, by blowhole, Collyer Point, 15 April 2008, NHMUK 2014.830-831; fcn ASC-083, 1♂, cw 7.4, 1 juv. intertidal, by blowhole, Collyer Point, 15 April 2008, NHMUK 2014.833; fcn ASC-138, 1♀, cw 11.7, 10 m, West side of English Bay, 16 April 2008, NHMUK 2014.834; fcn ASC-141, 1♀, cw 14.4, in rock pools, intertidal, English Bay, North Point, 16 April 2008, NHMUK 2014.835; fcn ASC-145, 1♂, cw 5.2, 15 m, west side of English Bay, 17 April 2008, NHMUK 2014.836; fcn ASC-157, 1♀, cw 15.8, in rock pools, intertidal, English Bay, North Point, 17 April 2008, NHMUK 2014.837; fcn C6/016, 2♂, cw 18.2, 18.2, 9 m, Darby Wreck, 21 August 2012, NHMUK 2014.865-866, NHMUK 2014.837; fcn C8/002,1♀, cw 10.3, Darby Beach, 22 August 2012, NHMUK 2014.867; fcn C10/003, 1♂, cw 13.7, Red Rock, 23 August 2012, NHMUK 2014.868; fcn C10/004, 1♀, cw 17.1, Red Rock, 23 August 2012, NHMUK 2014.869; fcn C20/007, 1♂, cw 15.5, 11 m, Sudan Wreck, 27 August 2012, NHMUK 2014.870; fcn C31/008, 1♂, cw. 15.9, diving, 12.8 m, North East Bay, 31 August 2012, NHMUK 2014.871; fcn C45/022, 1♀, cw 10.0, 12.4 m, Wigan Pier, 5 September 2012, NHMUK 2014.872; fcn C50/006, 1♂, cw 19.3, 12 m, Wigan Pier, 7 September 2012, NHMUK 2014.873.
DISCUSSION
Manning & Chace (Reference Manning and Chace1990) recorded 74 species of Decapoda from Ascension Island, including the terrestrial crab, Johngarthia lagostoma, and the anchialine shrimps, Procaris ascensionis and Typhlatya rogersi. All three of these species were also noted during the 2008 and 2012 surveys, but are herein not further reported upon. Since this study there have been few amendments to the fauna. The western Atlantic shrimp, Lysmata intermedia was recorded from Ascension by Manning & Chace (Reference Manning and Chace1990), however Manning (in litt.) in d'Udekem d'Acoz (Reference d'Udekem d'Acoz2000) indicates this to be a misidentification, with the specimens probably belonging to the east Atlantic L. seticaudata (see Table 2). Manning & Chace (Reference Manning and Chace1990) also discuss the presence of Latreillia manningi at Ascension, this species was, however, synonymized with L. elegans by Castro et al. (Reference Castro, Williams and Cooper2003) and is reported herein under that name. Fransen (Reference Fransen2006) in a partial key to Periclimenaeus, states Periclimenaeus atlanticus to be present on the island, however this is considered a lapsus (Fransen, in litt.). In addition to Corallianassa hartmeyeri reported by Manning & Chace (Reference Manning and Chace1990), C. longiventris is herein also recorded for Ascension Island. Only two species of shrimp have been added to the known fauna of the island since Manning & Chace (Reference Manning and Chace1990). De Grave (Reference De Grave, Fransen, De Grave and Ng2010) described Typton holthuisi from Comfortless Cove, noting that this species was potentially more widely distributed in the tropical eastern Atlantic. Anker & De Grave (Reference Anker and De Grave2012) described Alpheus cedrici from English Bay, a species still only known from Ascension. In the present contribution, a further species is added, the widespread Gnathophyllum americanum. Despite intensive collecting in 2008 and 2012, no additional crab species are reported herein.
The presently known marine Decapoda fauna thus stands at 75 species (Table 2), of which 12 species are considered to be endemic to the island. A full discussion of the biogeography of the marine decapod fauna is beyond the scope of the present contribution, but it is noted that the decapod fauna of St Helena is poorly known, being restricted to Chace (Reference Chace1966) and De Grave (Reference De Grave2007), who note 36 species to occur. There is a likelihood that a number of the endemic taxa recorded from Ascension will eventually be reported from St Helena.
ACKNOWLEDGEMENTS
This publication partly arises from research funded by the John Fell Oxford University Press Research Fund, who funded the 2008 OUMNH expedition to Ascension Island by S. and H. De Grave. The funding for the 2012 expedition came from a grant to Dr Paul Brickle from the Darwin Initiative (EIDCF012). We are grateful to the Shallow Marine Surveys Group and the South Atlantic Environmental Research Institute for organizing the 2012 expedition. We are also very grateful to Ascension Island Government, the members of staff at the Conservation Centre and Ascension Island Dive Club for their cooperation, accommodation and hospitality during both expeditions. Finally we are grateful to British Forces South Atlantic Islands for their logistical support to the 2012 expedition.