(177 SUlub) Stenaphorura lubbocki (Bagnall, 1935)

Species of Stenaphorura are white and blind, possess four anal spines (Fig. 1), and have an elongate post-antennal organ (PAO) with 70 or more small vesicles (Fig. 2).The foot does not possess an empodium. Stenaphorura lubbocki was described by Bagnall in 1935 but was considered until recently to be a junior synonym of Stenaphorura quadrispina. However, following examination of all the Stenaphorura slides in the NHML, Steve became convinced that Stenaphorura lubbocki is a good species. The longest specimen there is the lectotype which is 1.3 mm in length.
     The most easily observed characters which distinguish Stenaphorura lubbocki are head with setae p1 shorter than p2 (Fig. 3), seta m0 PRESENT on abd4 which has only one pseudocellus on each side (Fig. 4), seta m1 much longer than p2 on th2 and th3 (Fig. 5), and a seta PRESENT on either side of the m seta anterior to the anal spines (Fig. 1). These features may seem obscure but in cleared, well-orientated specimens viewed under phase contrast, they are unambiguous.
     Stenaphorura lubbocki may have a northeasterly bias to its distribution but more collecting is required to confirm this.

 

 

 

 

Fig. 1 (above): Sixth abdominal segment (abd6) of the lectotype of Stenaphorura lubbocki collected from Danes Dyke, E. Yorks. in August 1934 by Bagnall. There are four anal spines. A seta is present on either side of the m seta.

 

Fig. 2 (above): Post-antennal organ (PAO) of the same specimen of Stenaphorura lubbocki shown in Fig. 1.

 

Fig. 3: Posterior margin of the dorsal side of the head of the same specimen of Stenaphorura lubbocki shown in Fig. 1. The p1 setae are shorter than the p2 setae. th1, first thoracic segment.

 

Fig. 4: Dorsal side of the fourth abdominal segment of the same specimen of Stenaphorura lubbocki shown in Fig. 1. Seta m0 is present and there is only one pseudocellus (*) on each side.

 

Fig. 5 (above): Dorsal side of the third thoracic segment (th3) of the same specimen of Stenaphorura lubbocki shown in Fig. 1. The m1 setae are longer (red arrows) than the p2 setae.

 
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