Hypogastrura heptasetata, Jiang & Yin, 2010

Jiang, Jigang & Yin, Wenying, 2010, Two new Hypogastrura species (Hypogastruridae, Collembola) from China, Zootaxa 2542 (1), pp. 48-60 : 53-54

Hypogastrura heptasetata sp. nov.

Figs 19–36 , Tab. 2 and 3

Type material. Holotype male, China, Jiangsu Province, Suzhou City, Huqiu Mountain . 30 m alt. 31.viii.1998, Lijun Zhao coll. Paratypes, 3 females and 1 male, same data as the holotype. All types mounted on slide and deposited in Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences .

Description. Body length up to 1.6 mm. Body color in alcohol blackish grey. Integumentary granules fine and uniform. Dorsum of Abd. V with 10–12 granules between setae p 1.

Dorsal chaetotaxy of head, thorax and abdomen as in Figs 19–21 . Body setae weakly differentiated. Ventral cephalic chaetotaxy (after Fjellberg, 1998/99) with 6 proximal, 4 basomedian, 5 basolateral, and 2 postlabial setae ( Fig. 28 ). Th. I with 3+3 setae. Th. II setae m 2 and m 6 present. Th. III with m 6 present and m 2 absent. No setae on thoracic sternum. Abd. I–III respectively with three rows of setae, m 1 always absent, m 5 usually absent. Abd. IV polychaetotic, without a 5 and m 2. Abd. V with sensillum p 3, an additional seta a 0 always present on the body axis between a 1 setae ( Fig. 21 ).Ant. I with 7 setae and without p seta. Ant. II with 13 setae. Ant. III with microsensillum (ms) on ventral side, Ant. III organ with 2 short rods in separate foveae and 2 guard sensilla. Ant. IV with simple subapical bulb and 10 (4 outer and 6 inner) dorsolateral sensilla, i seta, microsensillum (ms) and subapical organite (os) ( Figs 24–25 ), ventral file with 10–15 short and pointed setae.

Eyes 8+8. Postantennal organ with 4 lobes, diameter about 0.9–1.2 times as large as nearest eye, accessory tubercle absent ( Figs 22–23 ).

Labral setae 4 /5, 5, 4 ( Fig. 26 ). Labial palp with only 4 papillae (A, B, D, E), papilla C absent, guard setae a 1, b 1–4, d 2–4, e 1–6 present, lateral process small ( Fig. 29 ). Mandible with basal molar plate, right mandible with 5 apical teeth ( Fig. 30 ), left mandible with 4 apical teeth. Maxilla lamella 1 with denticles on inner side, without filaments; lamellae 2 and 3 with long marginal filaments and no denticles; lamellae 4 and 5 with denticles on inner side, lamella 4 with dorsal marginal filaments, lamella 5 with dorsal and ventral marginal filaments; lamella 6 with fine denticles; lamellae 1, 2, 4, 5, 6 extending beyond maxillary teeth, only lamella 3 shorter than maxillary teeth ( Fig. 27 ). Maxillary outer lobe with 1 sublobal hair ( Fig. 31 ).

Unguis developed, with 1 inner tooth at 1/2 distance and without lateral teeth. Unguiculus with broad basal lamella, tip of apical filament reaching 2/3 distance of inner edge of unguis. Tibiotarsus with 1 differentiated pointed tenent hair, foot complex of hind leg shown in Fig. 36 . Number of setae on each segment of legs as in Table 2.

Ventral tube with 4+4 setae. Tenaculum with 4+4 teeth ( Fig. 33 ).

Manubrium with 10 posterior setae on each side ( Fig. 35 ). Dens with 7 posterior setae. Mucro slightly curved, without inner and outer lamellae, with distinct carina ( Figs 34–35 ). Ratio of dens: mucro as 1.5 (1.3– 1.8): 1; Male genital plate shown in Fig. 32 . Two anal spines on Abd. VI slim and curved, longer than basal papillae, ratio of their lengths as 1.8:1 ( Fig. 21 ).

Ecology. Found in soil under tiles and leaves.

Etymology. The name refers to the seven setae on dens.

Remarks. Hypogastrura heptasetata sp. nov. belongs to trybomi group. It is characterized by highly modified mouthparts and by having a seta a 0 on Abd. V. It is close to H. hargrovei Skarży ṅski, 2007 from USA in having highly modified maxilla, 2+2 axial postlabial setae, only 1 sublobal hair on maxillary outer lobe, labial palp with papilla C absent, and 1 pointed tenent hair on tibiotarsus. H. heptasetata sp. nov. differs from H. hargrovei in having Th. II seta m 2, 7 setae on dens and 10 sensilla on Ant. IV, while H. hargrovei lacks setae m 2 on Th. II, has 6 setae on dens and 6 sensilla on Ant. IV. H. heptasetata sp. nov. is also similar to H. hexasetata sp. nov. from Hubei Province ( China) and H. maxillosa from Siberia ( Russia) in sharing strongly modified maxilla, and weakly differentiated body setae. H. heptasetata sp. nov. differs from H. hexasetata sp. nov. by having a differentiated tenent hair on tibiotarsus, 7 dorsal setae on dens, unguis without lateral teeth, papilla C of labial palp absent, 2 axial ventral setae on head. While in H. hexasetata sp. nov., tibiotarsus has no differentiated tenent hair, 6 dorsal setae on dens, 2 pairs of lateral teeth on unguis, papilla C of labial palp present, head with 3 axial postlabial setae. Moreover, H. heptasetata sp. nov. can be distinguished from H. maxillosa by having Th. II setae m 2, unguis without lateral teeth, papilla C of labial palp absent and lamella 6 of maxilla longer than maxillary teeth. In H. maxillosa, Th. II is lacks m 2, the unguis have lateral teeth, labial palp papilla C is present and lamella 6 of maxilla is shorter than maxillary teeth. H. heptasetata sp. nov. differs from H. ireneae and H. maynardi in having small postantennal organ ( H. ireneae and H. maynardi have postantennal organ about twice as large as nearest eye). In Table 3, a summary of diagnostic characters separating H. heptasetata sp. nov. from other related species of the trybomi group is given.

Figures

FIGURES 19–23. Hypogastrura heptasetata sp. nov.: 19, dorsal cephalic chaetotaxy; 20, dorsal thoracic chaetotaxy; 21, dorsal abdominal chaetotaxy; 22, postantennal organ and eyes; 23, postantennal organ and eyes, another specimen.

FIGURES 24–29. Hypogastrura heptasetata sp. nov.: 24, Ant. I–IV, dorsal view; 25, Ant. III–IV, ventral view; 26, labrum; 27, maxilla, dorsal view; 28, ventral cephalic chaetotaxy; 29, labial palp.

FIGURES 30–36. Hypogastrura heptasetata sp. nov.: 30, mandible, right; 31. maxillary outer lobe; 32, male genital plate; 33, tenaculum; 34, mucro and dens, lateral view; 35, furcula; 36, foot complex of hind leg.