Hypogastrura gisini Strenzke, 1954

Skarżyński, Dariusz & Gwiazdowicz, Dariusz J., 2022, A redescription of Hypogastrura gisini Strenzke, 1954 (Collembola: Hypogastruridae) and description of a new related species from Crete (Greece), Zootaxa 5155 (1), pp. 52-60 : 53-55

Hypogastrura gisini Strenzke, 1954

Figs 1–11

Hypogastrura gisini Strenzke, 1954: 47

Type material. Paratypes: 2 females, 2 males, moist sand under dry fucus, about 10 meters from the waterline, Weissenhaus (Hohwachter Bay, Baltic Sea coast, Germany), 8.viii.1952 (sample 1099) ( MHNG) .

Other material. 4 females, 6 males, wrack-bed on sandy seashore, Femmøller Strand , Djursland, Jutland, Denmark, 21.iii.1994, leg. A. Fjellberg (94.037) ( AF) ; 3 females, 3 males litter under shrubs near beach, Elafonissi , Crete, Greece, 2.x.2002, leg. A. Fjellberg ( AF) ; 1 female, wrack-bed on pebble shore of the Black Sea near Odessa, Ukraine, 18.ix.1997, leg. D. Skarżyński, R.J. Pomorski, I. Kaprus’ ( DIBEC) .

Redescription. Habitus typical of the genus ( Strenzke 1954: Fig. 1 ). Body length 0.6–0.85 mm. Color mottled grey-violet to gray-black. Ventrally paler. Borders between abdominal segments pale. Tegumental granulation coarse and uniform, 5–6 granules between setae p 1 on Abd. V ( Fig. 1 ).

Body setae short (slightly longer on last abdominal segments), fine and smooth. Body sensilla (s) about two times longer than microsetae, fine and smooth. Chaetotaxy of head typical of the genus, with complete set of v-setae. Th. I with 3 + 3 setae. Dorsal chaetotaxy of Th. II and Abd. III–VI as in Figs 1–4 . Th. II with setae m 2, m 3 and m 4 present. Th. III with setae m 2 and m 3 absent and setae m 4 present. Setae a 6 on Th. II–III sometimes absent.Abd. IV with setae p 3 and p 7 present. Abd. V with setae p 2 present, setae m 1 usually absent (only one specimen from Denmark with unpaired setae m 1 present) and setae m 3 quite often present (usually unpairly). Subcoxae I, II, III with 1, 2, 3 setae, respectively. Microsensillum on Th. II present ( Fig. 2 ).

Ant. IV with simple apical vesicle, subapical organite (or), microsensillum (ms), 6–8 weakly differentiated cylindrical, curved sensilla (3 lateral and 3–5 dorsal) ( Fig. 5 ) and 5–7 short pointed setae in ventral field. Ant. IIIorgan with two long (outer) and two short (inner) sensilla. Microsensillum on Ant. III present ( Fig. 5 ). Ant. I with 7 setae (seta p’ absent).

Ocelli: 8 + 8. Postantennal organ 1.2–2.0 as long as neighbouring ocelli, with four lobes, the anterior pair slightly larger than posterior one. Accessory boss most often invisible ( Fig. 6 and Strenzke 1954: Figs 3, 4 ). Labrum without apical papillae. Labral setae 5, 5, 4, prelabrals 4. Maxillary head as in Fjellberg (1998: Fig. 11d ). Lamella 1 broadened at tip, protruding beyond teeth, with two fringes of long cilia. Labial palp as shown in Fjellberg (1999: Fig. 6 ). Outer maxillary lobe with two sublobal hairs.

Tibiotarsi I, II, III with 19, 19, 18 setae, respectively. Apical seta A1 weakly clavate, slightly longer than inner edge of claw. Claws without inner tooth. Empodial appendage lancet-like, basal lamella absent. Ratio empodial appendage/inner edge of claws = 0.25–0.4 ( Fig. 7 and Strenzke 1954: Figs 5, 6 ).

Ventral tube with four setae on each side. Retinaculum with 3 + 3 teeth.

Furca well developed (ratio dens + mucro/inner edge of claw III = 2.7–3.2). Dorsal side of dens with 7 setae and with coarse, uniform granulation. Ratio dens/mucro = 3–4. Mucro slightly curved, with globular tip and high outer lamella ending just before the apex ( Figs 8–11 and Strenzke 1954: Fig. 7a–c ).

Anal spines short (ratio anal spines/inner edge of claws III = 0.3–0.5), slightly curved, on separate papillae of same length as spines ( Fig. 3 and Strenzke 1954: Fig. 2 ).

Remarks. Strenzke (1954) described H. gisini on the basis of specimens collected in moist sand of beaches and salt meadows on the coast of the Baltic Sea (Hohwacht Bay - type locality and Flensburg Firth) and the North Sea (Sylt) in Germany. Then it was recorded from Provence ( Poinsot 1974; Thibaud 2017), Crete ( Ellis 1976 as H. cf. gisini ), Black Sea coast in Georgia ( Babenko et al. 1994), near Odessa in Ukraine ( Thibaud & Taraschuk 1997) and in Crimea (Kaprus’ et al. 2005), as well as from Kattegat in Denmark ( Fjellberg 1998). Unfortunately, the reliability of these data could have been questioned due to the fact that the incomplete original description (e.g,, lack of information on chaetotaxy) made it difficult to identify the species. The examination of the paratypes from the collection of Gisin (MHNG) and the available material from other collections (AF, DIBEC and NBCN) allowed for redescription of H. gisini , and also to raise H. cf. gisini sensu Ellis (1976) from Crete to a species level (see remarks to H. cretensis sp. nov.). The differences between H. gisini and H. cretensis sp. nov., as well as other species of the manubrialis group sensu Babenko et al. (1994) having a retinaculum with 3 + 3 teeth and a maxillary head of the H. vernalis type ( Fjellberg 1984), i.e. H. breviempodialis ( Stach, 1949) , H. tianshanica Martynova, 1970 and H. ubsunurensis Babenko, 1999 are presented in Tab. 1 .

Figures

FIGURES 1–4. H. gisini: 1, tegumental granulation of Abd. V; 2, chaetotaxy of Th. II; 3, chaetotaxy of Abd. III–VI; 4, chaetotaxy of Abd. V (variant). Abbreviations in text. Scale bar 0.01 mm.

FIGURES 5–11. H. gisini: 5, chaetotaxy of Ant. III–IV; 6, postantennal organ and ocelli; 7, claw III with empodial appendage; 8, dens and mucro; 9, mucro, lateral view; 10, mucro, lateral view (variant); 11, mucro, lateral view (variant). Abbreviations in text. Scale bar 0.01 mm.