Hypogastrura martiani, Skarżyński, 2009

Skarżyński, D., 2009, A New Species And A New Interesting Record Of The Genus Hypogastrura Bourlet, 1839 (Collembola, Hypogastruridae) From Ukraine, Acta Zoologica Academiae Scientiarum Hungaricae 55 (1), pp. 23-30 : 24-27

Hypogastrura martiani sp. n.

( Figs 1–13 )

Type material. Holotype: female on slide, Martian Cape near the town of Yalta (Crimean Peninsula, Ukraine), pine forest, litter and soil, 28.VII.1996, leg. MOSALOV ( SMNHL) . Paratypes (all on slides): 15 males (including 8 reproductive and 1 ecomorphic), 10 females (including 3 reproductive and 2 ecomorphic), 27 juv. (including 16 ecomorphic, 2 in ecdysis from non-ecomorphic to ecomorphic form), same data as above (48 paratypes SMNHL, 4 paratypes DBET) .

Other material examined. 1 male on slide, near the town of Yalta (Crimean Peninsula, Ukraine), pine forest, litter and moss, 14.II.2007, leg. O. HAUSTOV ; 3 males, 1 female, 3 juv., Hrestova Mountain near Livadia village (Crimean Peninsula, Ukraine), litter and moss, 10.XII.2006, leg. O. HAUSTOV ( SMNHL) .

Description. Body length 0.9–1.5 mm. Body colour bluish grey. Granulation fine and uniform, 8–16 granules between setae p 1 on abdominal tergum V ( Fig. 2 ).

Dorsal chaetotaxy of thorax and abdomen as in Figs 1–2 . Dorsal chaetotaxy of head typical of the genus. Dorsal setae short, thin, tapered, and smooth ( Fig. 5 ). Body sensilla (s) two to three times longer than surrounding setae, smooth. Thoracic tergum I with 3 + 3 setae. Thoracic tergum II with setae m 2–4 present and setae m 6 absent. Thoracic tergum III with setae m 3 present and setae m 2, m 4, and m 6 absent. Setae p 3 on abdominal tergum IV usually present; setae m 2 always absent. 6–8 setae between sensilla p 3 on abdominal tergum V. Macrochaetae near anal spines tapered. Subcoxa I–III with 1, 2, 3 setae respectively. Polychaetosis absent.

Antennal segment IV with simple apical vesicle, subapical organite (or), microsensillum (ms), 4 (3 lateral, 1 dorsal) thin, cylindrical, curved sensilla ( Fig. 3 ) and up to 10 short erect sensilla in the ventral file. Antennal III-organ with two long (lateral) and two short (internal) curved sensilla ( Fig. 3 ). Microsensillum on antennal segment III present. Antennal segment I with 7 setae.

Ocelli 8 + 8. Post antennal organ slightly smaller than neighbour ocelli, with 4 subequal lobes ( Fig. 4 ). Accessory boss invisible.

Labrum with 5, 5, 4 setae, 4 prelabrals, and 4–6 distal papillae. Head of maxilla of the tullbergi type, outer lobe with 2 sublobal hairs. Labium of the tullbergi type.

Tibiotarsi I–III with 19, 19, 18 setae, clavate tenent hairs 2 (A 1, A 7), 3 (A 1, A 2, A 7), 3–4 (A 1, A 2, A 7, B 2) respectively. Tenent hairs slightly longer than claws. Setae A 1 thicker and longer than others; setae B 2 on tibitarsi III more or less clavate, rarely pointed. Claws with small inner tooth above middle of inner edge; lateral teeth weakly visible. Empodial appendage with broad basal lamella and apical filament reaching 1/2 of claw inner edge ( Fig. 7 ).

Ventral tube with 4 + 4 setae. Retinaculum with 3 + 3 teeth.

Furca well developed ( Fig. 6 ). Dens with fine and uniform granulation and 6 setae. Mucro narrow with low outer lamella and about 1/3–1/4 as long as dens.

Anal spines short, set on small basal papillae ( Figs 2, 5 ).

tibiotarsus III, claws and empodial appendage mucro of form B.

Description of ecomorphic specimens. Numerous specimens collected in July exhibit features typical of ecomorphic forms of Hypogastrura boldorii DENIS, 1931 ( CASSAGNAU 1956) and Hypogastrura conflictiva JORDANA et ARBEA, 1992 ( ARBEA 2007). 1 male, 1 female, and 18 juveniles comparable with form B of H. boldorii ( CASSAGNAU 1956) have reduced mouthparts (head of maxillae small with indistinct lamellae; mandibles small with some indistinct apical teeth and without molar plates), small ocelli, claws (without inner tooth), empodial appendages ( Fig. 10 ), mucro ( Fig. 13 ), anal spines and short body setae ( Fig. 8 ). Of the tibiotarsal tenent hairs, only A 1 are clavate, while the remaining ones are shortened and pointed ( Fig. 10 ). Tegumentary granulation is coarse and irregular, especially on the last abdominal terga. On abdominal tergum IV and V, smooth plates made of joined granules are visible ( Fig. 8 ). 1 female of H. martiani sp. n. refers to the ecomorphic form C of H. boldorii ( CASSAGNAU 1956) . This specimen differs from form B in having more shortened and thickened claws, smaller empodial appendages with indistinct basal lamellae, all tibiotarsal tenent hairs pointed ( Fig. 11 ), mucrodens ( Fig. 12 ), and a coarse and regular tegumentary granulation ( Fig. 9 ). Moreover, mandibles are invisible in form C.

Although morphological signs of ecomorphosis in H. martiani sp. n. and H. boldorii sensu CASSAGNAU (1956) are similar, their life cycles are different. This former species reproduces in the summer (July), whereas the latter in the autumn (October). The occurrence of the reproductive form and the ecomorphic forms of H. boldorii sensu CASSAGNAU (1956) in the field is separated temporally due to ecoclimatic conditions. The coexistence of all forms of H. martiani sp. n. (non-reproductive/non-ecomorphic, ecomorphic B, ecomorphic C, and reproductive) at the same time and place is an interesting phenomenon in this context. Further studies are needed to explain the peculiar characteristics of this life cycle.

Etymology. Named after its terra typica, Cape Martian near the town of Yalta (Crimea,

Ukraine).

Discussion. The Hypogastrura viatica group is one of the largest within the genus and comprises about 30 species and forms characterized by weakly differentiated sensilla on antennal segment IV, the retinaculum with 3+3 teeth, the ventral tubus with 4+4 setae, broad basal empodial lamella, and tibiotarsi with more than one clavate setae ( NAJT et al. 1984, FJELLBERG 1985, BABENKO et al. 1994, CHRISTIANSEN & BELLINGER 1998, THIBAUD et al. 2004). Some of them, e.g. H. viatica (TULLBERG, 1872) , H. distincta (AXELSON, 1902) , and H. purpurescens (LUBBOCK, 1867) , are morphologically well defined and widely distributed; others are distinguished based on subtle morphological features, distributional patterns, and habitat preferences.

H. martiani sp. n. belongs to a group of species and forms that have 2, 3, 3–4 clavate tenent hairs on tibiotarsi I–III, 5–6 setae on dens, and no signs of polychaetosis. It is similar to two strictly Arctic species: H. tullbergii (SCHÄFFER, 1900) and H. concolor (CARPENTER, 1900) , from which it differs in the structure of the antennal III-organ ( H. tullbergii – additional sensilla present, H. martiani sp. n. and H. concolor – additional sensilla absent) and the shape of dorsal setae ( H. concolor – thick and serrated, H. martiani sp. n. and H. tullbergii – thin and smooth) ( NAJT et al. 1984, FJELLBERG 1985, BABENKO et al. 1994). Both of the Arctic species, which live in cold, open habitats, do not pass ecomorphosis in their life cycles, whereas two ecomorphic forms were discovered in H. martiani sp. n., which lives in forests of the temperate climatic zone. The new species relates also to some undescribed forms, such as “ H. tullbergii ” from Thuringia ( Germany) (see GISIN 1961), “ H. sp. Delieux” from Toulouse ( France) (see NAJT et al. 1984) and “ H. cf. subboldorii ” from Bashkiria, the Caucasus Mountains, and the Altai Mountains (see BABENKO et al. 1994). However, further studies are needed to establish their actual taxonomic status and affinities. H. boldorii DENIS, 1931 from the Italian Alps, and H. browni ( BAGNALL, 1940) from Great Britain are possible relatives of the new species; however, their poor diagnoses ( DENIS 1931 a, b, BAGNALL 1940, LAWRENCE 1962) make comparison with the new species difficult. H. boldorii is commonly regarded as a species characterized by well-developed polychaetosis and therefore related to H. affinis (LUCAS, 1846) sensu JORDANA et al. (1997) (NW Africa, SW Europe), H. aequepilosa ( STACH, 1949) (Central Europe), H. conflictiva (SW Europe), H. elegantula (BUTSCHEK, 1948) (Austrian Alps) , H. litoralis (AXELSON, 1907) (N Europe), and H. subboldorii DELAMARE DEBOUTTEVILLE et JACQUEMART, 1962 (French Pyrenees) ( GISIN 1961, NAJT et al. 1984, FJELLBERG 1998). Due to its morphology, geographic range, and ecological preferences, H. browni is considered to be a synonym of H. litoralis , which inhabits bogs and seashores in Finland, Sweden, Denmark, and Russian Karelia ( FJELLBERG 1998, HOPKIN 2007).

Figures

Figs 1–7. Hypogastrura martiani sp. n.: 1 = chaetotaxy of thoracic tergum II; 2 = chaetotaxy of abdominal terga III–VI; 3 = chaetotaxy of antennal segments III–IV, dorsal view; 4 = post antennal organ and neighbour ocelli; 5 = anal spine and neighbour seta, lateral view; 6 = dens and mucro; 7 =

Figs 8–13. Hypogastrura martiani sp. n. (ecomorphic forms): 8 = tegumentary granulation and chaetotaxy of abdominal terga IV–VI of form B; 9 = tegumentary granulation and chaetotaxy of axial area of abdominal tergum IV of form C; 10 = tibiotarsus III, claws and empodial appendage of form B; 11 = tibiotarsus III, claws and empodial appendage of form C; 12 = mucrodens of form C; 13 = dens and