Bulbamphiascus denticulatus ( Thompson, 1893 )
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publication ID |
https://doi.org/ 10.1080/00222930500060397 |
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persistent identifier |
https://treatment.plazi.org/id/03B28791-FA23-FFC2-FEFC-89B9FD83FA89 |
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treatment provided by |
Felipe |
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scientific name |
Bulbamphiascus denticulatus ( Thompson, 1893 ) |
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Bulbamphiascus denticulatus ( Thompson, 1893)
( Figures 8 View Figure 8 , 9 View Figure 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 View Figure 8 ) a single median ventral row of coarse spinules on posterior margin of urosomite 4 and on anal somite at base of caudal rami.
Antennule ( Figure 9C View Figure 9 ) 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 View Figure 8 ) as in female except with additional row of spinules on ventral posterior border of urosomite 3.
Antennule ( Figure 9B View Figure 9 ) 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 View Figure 8 ) 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 View Figure 9 ), identical to that found in B. imus .
P5 ( Figure 8F View Figure 8 ) 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).
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