Apseudopsis latreilli (Milne Edwards 1828)

Bamber, Roger N., 2011, The marine fauna and flora of the Isles of Scilly. Tanaidacea (Crustacea: Peracarida), Journal of Natural History 45 (29 - 30), pp. 1801-1815 : 1805-1806

Apseudopsis latreilli (Milne Edwards 1828)

Apseudes latreilli Holdich and Jones, 1983 , 30–31; fig. 7.

Material

Rare , Hedge Rock, west of St Martin’s, 1 April 2001 ; common, Church Ledge , St Martin’s, 3 April 2001 ; common in sandy gravel at west end and north of causeway to White Island , northwest St Martin’s, 7 April 2001 ; 9♀♀, low-littoral Audouinella - bedded sand on boulders, south side of causeway to White Island , northwest St Martin’s, 7 April 2001 ; rare, Hatt Cardinal Buoy and Watermill Cove, St Mary’s, 8 April 2001 ; common to abundant in littoral sands at all tide levels, including brooding females, across St Martin’s Flats , 9 April 2001 ; 2♀♀ ( BMNH 2009.287 – 288 ), lowlittoral Audouinella -bedded sand, Thomas Porth , St Mary’s, 49 ◦ 55.18 ′ N, 06 ◦ 18.56 ′ W, 27 June 2009 ; 1♀, 49 ◦ 57.25 ′ N, 06 ◦ 17.70 ′ W, coarse sand with shell-breccia, some silt-clay, 4 m depth, van Veen grab, 28 June 2009 ; 4♂♂, 20♀♀ (3 brooding, 1 with oostegites), 10 neuters ( NMW 2009.034.6), 49 ◦ 57.77 ′ N, 06 ◦ 18.36 ′ W, macroalgae on gravel, 10.3 m depth, Tjärnö dredge, 28 June 2009 ; 1 juvenile, 49 ◦ 54.46 ′ N, 06 ◦ 27.09 ′ W, rocks with tunicates, algae and sediment scraping, 71 m depth, Tjärnö dredge, 29 June 2009 ; 1♀, 2 neuters, 1 manca, mid-shore coarse sand, Periglis Cove , St Agnes, 49 ◦ 53.68 ′ N, 06 ◦ 21.05 ′ W, 9 September 2010 ; 1 neuter, open sand, LWST, off Old Quay , St Martin’s Flats, St Martin’s, 49 ◦ 57.46 ′ N, 06 ◦ 17.41 ′ W, 10 September 2010 ; 53♀♀ (9 brooding), 3♂♂, 31 neuters, open sand with Ensis and Leptosynapta, LWST , western end of St Martin’s Flats , St Martin’s, 49 ◦ 57.55 ′ N, 06 ◦ 17.76 ′ W, 11 September 2010. All coll. RNB.

Other unpublished material examined

One ♂, 1♀ with oostegites, 2 neuters, sediment under stone, Pergelis, St Agnes, 11 September 2006 (coll. P R Garwood); 1♂, 2 neuters, littoral, Old Grimsby, Tresco, 10 September 2006 (coll. P R Garwood) .

Other records

One specimen, off Darrity’s Hole, St Mary’s, 49 ◦ 55.44 ′ N, 06 ◦ 16.48 ′ W, 13 July 1983 ( Rostron 1983: CBRU Record No. W75247); eight further station records (Crow Bar, St Mary’s; west English Island, St Martin’s; Darrity’s Hole, St Mary’s; St Helen’s Pool, Tresco; Old Grimsby Harbour, Tresco), July 1983 ( Rostron 1983); Tresco Flats, 49 ◦ 56.13 ′ N, 06 ◦ 20.97 ′ W, 21 September 1988 ( Rostron 1988: CBRU Record No. W91956). Tresco Flats, 49 ◦ 56.6 ′ N, 06 ◦ 20.3 ′ W; off Cromwell’s Castle, Tresco, 49 ◦ 57.6 ′ N, 06 ◦ 20.9 ′ W; east of White Island, St Martin’s, 49 ◦ 58.4 ′ N, 06 ◦ 16.8 ′ W; southwest of Crow Rock, St Mary’s, 49 ◦ 56.1 ′ N, 06 ◦ 18.9 ′ W (all September 1988; Rostron 1988). Numerous unspecified records off St Mary’s and on St Martin’s Flats in October 1997, and including 1 specimen, St Agnes, 49 ◦ 54.23 ′ N, 06 ◦ 20.12 ′ W, 22 October 1997; 89 specimens, St Martin’s Flats, 49 ◦ 57.68 ′ N, 06 ◦ 17.66 ′ W, 17 October 1997; 592 specimens, St Mary’s, 49 ◦ 54.49 ′ N, 06 ◦ 18.06 ′ W, 22 October 1997; 837 specimens, St Martin’s, 49 ◦ 57.43 ′ N, 06 ◦ 18.59 ′ W, 22 October 1997; all Munro and Nunny (1998). 1 specimen, Darrity’s Hole, St Mary’s, 49 ◦ 55.43 ′ N, 06 ◦ 16.73 ′ W; 1 specimen, Penninis Head, St Mary’s, 49 ◦ 54.35 ′ N, 06 ◦ 18.02 ′ W; various further records without precise locality, St Mary’s and Tresco; all August 2000 (Kendall in MarLIN). Five station records (20, 23, 33, 33 and 152 specimens), St Mary’s Flats, 15 to 17 October 2004 (Warwick in MarLIN). (All as Apseudes latreilli .)

From quantitative surveys on St Martin’s Flats (see Warwick 2010), in summer 2000 densities in the Ensis -community off Old Quay averaged 54 individuals per m 2, and in the Arenicola -community near “Neck of the Pool” two individuals per m 2; in 2004 the species was only found in the Ensis -community, at densities of 522 individuals per m 2; none were found in any samples in 2001 (restricted survey) or 2009 ( R. Warwick, unpublished data).

Remarks

Apseudopsis latreilli is common in the littoral and near-littoral sands of the Isles of Scilly (frequently observed, rarely recorded), and can be particularly numerous, as found consistently over the years on St Martin’s Flats, although that population appears to have collapsed in 2009 (see above and Warwick 2010) and few individuals were found there in September 2010. As stated above, it is largely separated in habitat from the deeper-occurring Apseudes talpa (that species not occurring in the open sand-flats), although some of the early deeper records of the present species in litt. may have confused the two. These two species were sympatric (although infrequent) in low-littoral Audouinella -bedded sand.

Holdich and Jones (1983) list the occurrence of this species in the Isles of Scilly, as well as from southern coasts of England, the Channel Isles and French coasts (their records from northeastern coast of England are based on a lapsus calami by Bate and Westwood 1868, see Bamber 2000).