Ceratophysella macrocantha Stach, 1946

Skarżyński, Dariusz, 2019, Ceratophysella macrocantha Stach, 1946 (Collembola, Hypogastruridae): a redescription of a forgotten species from the Alps, Revue suisse de Zoologie 126 (2), pp. 151-154 : 151-152

Ceratophysella macrocantha Stach, 1946

Figs 1-8

Type material: Female lectotype, designated here, previously in alcohol, now mounted on permanent slide, deposited in the Institute of Systematics and Evolution of Animals, PAS, Cracow , Poland; Styrian Alps, Buchau, east ridge, about 850 m asl., in beech forest on the south slope; 21 October 1941; leg. H. Franz.

Diagnosis: Body size large. Tegumental granulation fine and uniform. Chaetotaxy of the type B, setae p 3 on abdominal tergum IV absent. Antennal segment IV with trilobed apical vesicle, 7 cylindrical sensilla and about 18 slightly modified sensilla in ventral field. Eversible sac between antennal segments III and IV weakly developed. Head of maxilla with lamella 1 protruding beyond the teeth and broadened at the tip. Outer maxillary lobe with two sublobal hairs. Empodial appendage with apical filament reaching tip of claw. Dens with 7 unmodified setae, mucro slender, spoonlike at tip, with low outer lamella. Anal spines long colourless.

Redescription: Body length 2.4 mm. Colour (in alcohol) mostly dark blue, ventrally paler. Tegumental granulation fine and uniform, 27 granules between widely spaced macrosetae p 1 on abdominal tergum V ( Fig. 6 ).

Arrangement of setae on head typical for the genus, spinelike setae absent. Dorsal chaetotaxy of type B ( Figs 5-6 ). Thoracic tergum II with setae m 3 and m 4 present, setae a 2 similar to a 3. Setae p 1 on abdominal tergum IV developed as macrosetae, p 2 as microsetae, setae p 3 absent, additional setae m 2 present. Abdominal tergum V with long a-setae, setae p 2 present. Differentiation of dorsal setae into micro- and macrosetae distinct. Setae long (ratio p 5 macrosetae on abdominal tergum II/inner edge of claws III = 1.7), straight, pointed at tips and slightly serrate. Body sensilla (s) relatively long, but mostly shorter than macrosetae (only on abdominal tergum V slightly longer). Microsensilla (ms) on thoracic tergum II present ( Fig. 5 ). Subcoxae I, II, III with 1, 2, 3 setae, respectively.

Antennal segment IV with trilobed apical vesicle, subapical organite (or), microsensillum (ms), 7 (2 lateral, 5 dorsal) cylindrical, subequal sensilla and about 18 thin, slightly curved and blunt-tipped sensilla in ventral field ( Fig. 1 and Stach, 1946: pl. II, fig. 1). Antennal segment III organ with two long (lateral) and two short (internal) curved sensilla ( Fig. 1 ). Microsensillum on antennal segment III present. Eversible sac between antennal segments III and IV present but weakly developed. Antennal segment I with 7 setae.

Ocelli: 8 + 8. Postantennal organ 2.6 times as large as single ocellus; the former with four lobes, its anterior pair larger than posterior pair. Accessory boss present ( Fig. 2 ).

Labrum with 5, 5, 4 setae; 4 prelabrals present. Maxillary head (not well visible) as in Figs 3 and 4 . Lamella 1 broadened at tip, protruding beyond teeth. Outer maxillary lobe with two sublobal hairs. Labium hardly visible.

Tibiotarsi I, II, III with 19, 19, 18 setae, respectively. Tenent hairs a little shorter than inner edge of claws, pointed. Claws with inner tooth and a pair of lateral teeth. Empodial appendage with broad lamelliform base and filiform apex reaching tip of claw ( Fig. 7 ).

Ventral tube with 4 + 4 setae. Furca well developed. Ratio dens + mucro/inner edge of claw III = 2.2, ratio dens/mucro = 2.1. Dens with uniform fine granules and 7 unmodified dorsal setae (basal macroseta slightly exceeding half of dens length). Mucro slender, spoonlike at tip, with low but distinct outer lamella ( Fig. 8 ). Retinaculum with 4 + 4 teeth.

Anal spines long (1.4 times as long as inner edge of claws III), slightly curved, situated on basal papillae, unpigmented ( Fig. 6 ).

Remarks: Ceratophysella macrocantha , having chaetotaxy of the type B and an empodium with a long filament, is similar to six European species/forms of the armata group: C. attenuata Gisin, 1960 nec Cassagnau, 1959 (Swiss Alps, from cave), C. lawrencei Gisin, 1963 (Alps, Appenines, Carpathians), C. penicilifer Cassagnau, 1964 ( France - Massif Central), C. recta Cassagnau, 1959 (Pyrenees) , C. scotica ( Carpenter & Evans, 1899) ( Belarus, Germany, Great Britain, Ireland, Norway, Poland, Ukraine) and C. tergilobata ( Cassagnau, 1954) (Mediterranean) , and also to three Asian species: C. empodialis Babenko et al., 1994 ( Russia - Far East), C. liguladorsi Lee, 1974 ( Korea, China, Russia - Southern Sachalin, Indonesia) and C. paraliguladorsi Nguyen, 2001 ( Vietnam) (see Gisin, 1960; Babenko et al., 1994; Thibaud et al., 2004; Nguyen, 2001; Skarżyński, 2006).

Ceratophysella tergilobata , C. liguladorsi and C. paraliguladorsi can be easily distinguished from C. macrocantha by the presence of a characteristic medial spine-like integumentary projection between the bases of setae p 1 on abdominal tergum V. Easy to distinguish are also C. lawrencei and C. scotica (integument with fields of coarse granules), C. penicilifer (six setae on dens, filament of empodium split into three or four branches) and C. empodialis (boat-like mucro as typical for the genus).

Closest to C. macrocantha (probably conspecific) seem to be C. recta and C. attenuata . Both differ from the species redescribed here in subtle characters. The first of the above-mentioned has a simple apical vesicle on antennal segment IV, the filament of the empodium ¾ the length of the inner edge of the leg claws, the mucro is almost without an outer lamella and the tenent hairs on the tibiotarsi are clearly longer than the claws. Ceratophysella attenuata , of which I examined four specimens (3 females, 1 male on one slide labelled by Gisin : Ceratophysella attenuata, Fikenloch , cave near Jochpass, canton Obwald, central Switzerland, 2450 m asl., 18.08.1959, leg. M.M. Aellen, Roth and Strinati, deposited at the Muséum d’histoire naturelle in Geneva, Switzerland), differs from C. macrocantha by a shorter filament of the empodium (¾ the length of the inner edge of the claws), by a lower outer lamella on the mucro and by characters which can be the result of evolution in an isolated cave system: very long macrosetae (ratio p 5 on abdominal tergum II/inner edge of claws III = 2.5), slightly enlarged and modified postantennal organ (ratio postantennal organ/nearest ocellus = 3, presence of a single small finger-like papilla on one of the four primary lobes) and reduced body pigmentation (only blue-black spots present). To clarify taxonomic relations between these three species/forms further research based on more extensive material is needed.

Figures

Figs 1-8. Ceratophysella macrocantha Stach, 1946. (1) Chaetotaxy of antennal segments III and IV, dorsal side. (2) Postantennal or- gan and adjacent ocelli. (3) Maxillary head, dorsal side. (4) Maxillary head, ventral side. (5) Chaetotaxy of thoracic tergum II. (6) Chaetotaxy of abdominal terga III-VI. (7) Claw III with empodial appendage. (8) Dens and mucro of furca. Scale lines: 1-2; 3-4; 5-6; 7-8 to same scale. Abbreviations: or - subapical organite on antennal segment IV; ms - microsensillum; a1, a2, a3 - setae of a-row; m2, m3, m4 - setae of m-row; p1, p2, p4 - setae of p-row; s - body sensilla; 1, 2, 3, 4, 5, 6 - maxillary lamellae. The longitudinal axis of the body is indicated by a broken line. ►