(073/ADimm) Anuridella immsiana (Bagnall, 1939)

Anuridella immsiana (maximum length 1.0 mm) is an intertidal species which has only been recorded by Bagnall. He described it in 1939 from material collected in July 1938 from Cloughey, Co. Down, Ireland. Lawrence & Goto (1968) considered that Anuridella immsiana was a junior synonym of Anuridella calcarata Denis 1925. However having examined Bagnall's material in the NHML, Steven agreed with the conclusion of Fjellberg (1998) that Anuridella immsiana is a good species. The post-antennal organ (PAO) is circular with typically ten (but occasionally up to 12) vesicles (Fig. 1). Also, the pair of setae a1 on the dorsal side of abd6 are PRESENT (Fjellberg 1998); this character is easy to observe on most specimens (Fig. 2). Coxal lobes are present on both legs2 and legs3 but they are quite difficult to resolve on mounted specimens. Anuridella immsiana and Anuridella submarina (and Anuridella calcarata) have hammer-shaped sensillae on ant4 (all sensilla are finger-like in Anuridella marina).

 

 

 

Map Anuridella immsiana
Post-antennal organ (PAO) of Anuridella immsiana

Fig. 1: Post-antennal organ (PAO) of Anuridella immsiana collected from Whitburn, Durham in June 1939 by R.S. Bagnall. There are 12 lobes.

Chaetotaxy on the dorsal side of the sixth abdominal segment of Anuridella immsiana

Fig. 2: Chaetotaxy on the dorsal side of the sixth abdominal segment (abd6) of Anuridella immsiana collected from Whitburn, Durham in June 1939 by R.S. Bagnall. The a1 setae are PRESENT.

Apical part of the left mandible of Anuridella immsiana

Fig. 3: Apical part of the left mandible (at two levels of focus) of Anuridella immsiana collected from Cloughey, Co. Down, Ireland in July 1938 by R.S. Bagnall.

 
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