Two new species of Bulbamphiascus Lang (Copepoda: Harpacticoida: Diosaccidae) from Scotland and the Isles of Scilly, with additional observations on B. denticulatus (Thompson) Author Gee, J. Michael text Journal of Natural History 2005 2005-09-30 39 22 1961 1979 http://dx.doi.org/10.1080/00222930500060397 journal article 10.1080/00222930500060397 1464-5262 5215174 Bulbamphiascus denticulatus ( Thompson, 1893 ) ( Figures 8 , 9 ) Material examined Thirteen ♀♀ (one dissected on to three slides), 35 „„ (one dissected on to four slides) and seven copepodids from coarse intertidal sand on St Martin’s , Isles of Scilly , NHM Reg. Nos 2004.4180–4191 . Description of female As described by Thompson (1893) and Sars (1911) except with the following additions. Body length 0.665–0.85 mm (mean 50.73 mm , n 58). Urosome ornamentation ( Figure 8A, B ) a single median ventral row of coarse spinules on posterior margin of urosomite 4 and on anal somite at base of caudal rami. Figure 8. Bulbamphiascus denticulatus ( Thompson, 1893 ) . ♀: (A) urosome (excluding urosomite 1), lateral; (B) urosome (excluding urosomite 1), ventral. „ : (C) urosome (excluding urosomite 1), lateral; (D) urosome (excluding urosomite 1), ventral; (E) P1 protopod; (F) P5. Figure 9. Bulbamphiascus denticulatus ( Thompson, 1893 ) . „ : (A) P2 (hyaline structure arrowed); (B) rostrum and antennule. ♀: (C) segmentation of antennule. Antennule ( Figure 9C ) with pronounced apophysis at outer distal corner of segment 2; this and segment 4 slightly longer than in B. imus but armature of all segments as for that species. Mouthparts as in B. imus . Description of male As described by Sars (1911) except with the following additions. Body length 0.55–0.695 mm (mean 50.59 mm , n 510). Urosome ornamentation ( Figure 8C, D ) as in female except with additional row of spinules on ventral posterior border of urosomite 3. Antennule ( Figure 9B ) 11-segmented as result of segment 9 in B. imus being divided into two segments, total armature as in B. imus . P1 basis ( Figure 8E ) with single chitinous projection at inner distal corner. P2 basis with large tapering, tubiculate, semi-hyaline projection at inner distal corner (arrowed in Figure 9A ), identical to that found in B. imus . P5 ( Figure 8F ) exopod with six well-developed armature elements of somewhat different lengths to those shown in Sars (1911 , suppl. Plate 18) and with both distal outer elements distinctly swollen as base. Remarks These observation show that the hyaline structure on the basis of the male P2 endopod in B. denticulatus is exactly the same shape as that found in B. imus by Mu and Gee (2000) and that the ornamentation of the urosome and the structure of the P 5 in both sexes is also as described for B. imus . With the possible exception of the segmentation of the male antennule, this confirms the observation of Sars (1911) that the only feature by which B. denticulatus can be distinguished from B. normani (a synonym of B. imus ) is in the attenuation into a thorn-like process of the outer distal corner of segment 2 of the antennule in both sexes. This appears to be the first genuine record of B. denticulatus in the Scilly Isles. It was not entered in the faunal list of Wells (1970) and although Lang (1948) records that Brady (1905) found it in the Scilly Isles on St Mary’s Island, the island to which Brady refers is St Mary’s off the coast of Northumberland . The preferred habitat of this species is coarse sand or shell gravel and virtually the only record from muddy sediments (inside Port Erin harbour) is that of Thompson (1893) .