Hymenaphorura subsimilis Bagnall, 1948

Weiner, Wanda Maria & Fiera, Cristina, 2020, Two new species of Hymenaphorura Bagnall, 1948 (Collembola, Onychiuridae) from Romania and an updated key to the genus, ZooKeys 960, pp. 17-38 : 17

Hymenaphorura subsimilis Bagnall, 1948 Figures 5A-E , 6A-C , Table 1

Material examined.

Type specimen (NHMUK 012816837): Romania, Prahova, Sinaia, July 1934, coll. M. Manolache, among dead needles of Larix .

Complementary description.

Antennae and head. AIIIO consisting of four guard setae, five papillae, two smooth sensory rods, two granulated sense clubs: ribbed and bent (Fig. 4A ). PAO with 12-13 simple vesicles (Fig. 5C , 6A ). Labial type A (sensu Fjellberg 1999) with four papillae, papilla E absent.

Dorsal chaetotaxy. Dorsal chaetotaxy as in Fig. 4B always with some asymmetry. Seta d0 on the head absent. Body with macro- and meso-microsetae and sensory setae s (slightly distinguished) on head, abdominal terga I, IV and V, their formula per half tergum: 2/000/10012.

Thoracic terga II and III with strong lateral microsensilla (ms). Thoracic tergum I with 4+4 setae. Thoracic terga II and III (Figs 5D , 6B ) and abdominal terga I-IV with 1+1 microsetae (a1) along midline. Setae p2 and p3 on abdominal terga I-III subequal. Abdominal tergum V (Figs 5D , 6C ) with four long macrosetae (a4, m4, p2 and p5).

Chaetotaxy of anal valves. Each of even anal valves with 3 setae in row a (a1-a0-a1) and five setae in b-row (b2-b1-b0-b1-b2); upper valve with one seta in a-row (a0), four setae in b-row (b2-b1-b0-b1-b2) and with three setae in row c (c2-c0-c2), c0 is distinctly longer than c2 (Fig. 5E ).

Legs. Distal whorl of tibiotarsi with 11 setae. Empodial appendage with small, narrow basal lamella, length of empodium is about 2/3 of inner edge of claw.

Remarks.

In the Collembola collection in the Natural History Museum, London, only a single type microscope slide exists of Hymenaphorura subsimilis , which was described by Bagnall (1948). This slide is in a poor condition, with some characters not well visible or completely invisible. Salmon (1959) redescribed the type specimen, but without details of the chaetotaxy. We had an opportunity to study this type specimen, and we found that the description of H. subsimilis was probably based on a juvenile or anomalous specimen, because there is only seta a1 in the medial part of terga (Figs 6A , 5D ) without m1 or p1 and also with only 4+4 setae on Th. I.

Figures

Figure 4. Hymenaphorura urbana sp. nov.: dorsal chaetotaxy. A head B thoracic tergum II C abdominal tergum II D abdominal tergum IV E abdominal tergum V F abdominal tergum VI.

Figure 5. Hymenaphorura subsimilis Bagnall, 1948. A ant III sensory organ B habitus and dorsal chaetotaxy C postantennal sensory organ and anterior cephalic pseudocellus D abdominal terga V and VI E abdominal sternum VI: anal valves. Scale bars: 0.01 mm (A, C); 0.1 mm (B); 0.05 mm (D, E).

Figure 6. Hymenaphorura subsimilis Bagnall, 1948. A postantennal sensory organ and anterior cephalic pseudocellus B thoracic tergum II C abdominal tergum V.