(013/HYass) Hypogastrura assimilis (Krausbauer, 1898)

The only literature record for Hypogastrura assimilis is that of Greenslade & Fletcher (1986) who reported this species from earthworm culture boxes at Rothamsted. However, there are two specimens labelled 'Hypogastrura manubrialis' in the NHML collection from 'under cut grass' and 'hop manure' in Kew Gardens collected in the early 1960s which correspond to the description of Hypogastrura assimilis in Babenko et al. (1994) and Fjellberg (1998). The most definitive character is very difficult to see unless the mouthparts of the specimen are extruded beyond the buccal cone of the mouth. In Hypogastrura manubrialis the maxillary lamella 1 has an expanded 'double-ciliated' apex whereas in Hypogastrura assimilis, lamella 1 has only a single fringe of setae (Fig. 1). Also, there is a small papilla-like projection at the base of each lobe of the PAO in Hypogastrura assimilis (Fig. 2). There is only one clavate seta on the tibiotarsus of each foot (tt clavate setae formula 1:1:1). 

Paradoxically, the few specimens labelled Hypogastrura assimilis in the NHML collection are all Hypogastrura manubrialis.

 

 

 

Map Hypogastrura assimilis
Maxilla of Hypogastrura assimilis

Figure 1: Maxilla of Hypogastrura assimilis collected from Kew Gardens in February 1961 by J.L. Gilbert. Lamella 1 has only a single fringe of setae.

Post Antennal Organ

Figure 2: Post Antennal Organ (PAO) adjacent to ocelli A to E (F,G and H are out of the picture) of the same specimen as shown in Fig. 1. At the base of each of the main lobes (PAO), there is a small papilla-like projection (pap).

Furca

Figure 3: Furca of the same specimen as shown in Figure 1.

Foot of the third leg

Figure 4: Foot of the third leg of the same specimen as shown in Fig. 1. There is only one clavate tenant seta (ts) and the empodium (emp) is about half as long as the claw.

 
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