Heteromurus (Verhoeffiella) gamae, Lukić, Marko, Porco, David, Bedos, Anne & Deharveng, Louis, 2015

Lukić, Marko, Porco, David, Bedos, Anne & Deharveng, Louis, 2015, The puzzling distribution of Heteromurus (Verhoeffiella) absoloni Kseneman, 1938 (Collembola: Entomobryidae: Heteromurinae) resolved: detailed redescription of the nominal species and description of a new species from Catalonia (Spain), Zootaxa 4039 (2), pp. 249-275 : 271-272

Comparison of H. (V.) absoloni , H. (V.) gamae sp. nov. and H. (H.) nitidus

Additional material examined. H. (V.) nitidus , Bosnia and Herzegovina, Romanija, Rogatica, Golubovići, Golubina pećina (cave) (coordinates WGS 84 X =18.91642°, Y =43.78418°, alt. 800 m.), 4 ex. on slide, 3 ex. in 96% alcohol, 14.xiii.2010, M. Lukić leg. (CLL 2325).

Dorsal macrochaetotaxy ( Figs 50–53 ). Dorsal macrochaetotaxy provides the main diagnostic characters to separate species and genera across Entomobryoidea when there is no color pattern, as it is the case for troglobiotic species. Macrochaetotaxic pattern of H. (V.) absoloni and H. (V.) gamae sp. nov. is identical on most tergites but exhibits important differences on head and Abd. IV ( Figs 52, 53 ). Differences on head concern the number of mac in anterior (3+3 with one unpaired vs 2+2 without unpaired), median (2+2 vs 1+1), antennal (8 vs 6) and sutural (6+6 vs 6–7+6–7) groups on head. The 1+1 chaetae between antennae are absent in H. (V.) gamae sp. nov. Differences on body concern the chaetotaxy of Abd. IV ( Figs 52, 53 ): number of mac in medial (3 vs. 4), anterolateral (4 vs 3) and posterolateral (4 vs 2) groups in H. (V.) absoloni versus H. (V.) gamae sp. nov. Additionally, specimens of H. (V.) gamae sp. nov. have 1 or 2 mac in posteromedial group.

Described macrochaetotaxic pattern of H. (V.) gamae also differs from the standard macrochaetotaxic pattern of Heteromurinae recognized in H. (H.) nitidus ( Fig. 50 , see also Szeptycki 1972, Szeptycki 1979) and H. (H.) major (see Hüther 1970, Mari-Mutt 1980a) in several features such as: absence of unpaired mac in anterior group, difference in the number of mac in anterior and antennal group, absence of 1+1 chaetae between antennae and macrochaetotaxic pattern on Abd. IV. The most troglomorphic species of the subgenus Verhoeffiella regarding claw elongation, collected in a cave of Cantabria and identified as V. cf. longicornis by Gama (1984), departs even more from the standard pattern, while H. (V.) hispanica from province Oviedo has, according to Gama (1984), the standard pattern of Heteromurinae. The evolutionary stasis of the dorsal macrochaetotaxy pattern, suggested by its remarkable similarity between several species very different otherwise, is therefore not retrieved in 2 of the 3 iberic species of the genus.

Labial triangle ( Figs 54–56 ). Number of chaetae of the labial triangle is variable in the genus Heteromurus according to Mari-Mutt (1980b), who did not considered it as a good taxonomic character. However, the author did not analyzed this variability in populations, and used the presence/absence of ciliated chaetae (but not their number) as one of the character for separating Heteromurus (H.) in two groups (group major and group nitidus ). Actually, from our observations, the variation in number of chaetae is relatively limited within populations. The number of chaetae in the labial triangle, expressed as ranges, may be therefore a valuable taxonomic character within Heteromurinae. In both H. (V.) absoloni and H. (V.) gamae sp. nov. this number fluctuates within a narrow range of 9–12+9–12 chaetae, compared to 6–8+ 6–8 in H. (H.) nitidus examined from various localities. All chaetae of examined populations of H. (H.) nitidus and those of H. (V.) absoloni are smooth like in H. (H.) nitidus group of Mari Mutt (1980), while in H. (V.) gamae sp. nov. there is at least 1+1 serrated chaetae among the smooth ones ( Fig. 55 ).

Tibiotarsus. H. (V.) gamae sp. nov. has no smooth mes on tibiotarsus beside the dorsal tenent hair and the ventro-distal smooth mes of Tita III, contrary to H. (V.) absoloni where there are several smooth mes arranged in two rows in the 1/3 ventro-distal part of Tita, and to H. (H.) nitidus , where these two rows run all along Tita length.

Claw ( Figs 57–59 ). Claw is very different in the three forms of interest in its degree of elongation, curvature and position of inner tooth. Unguis of H. (V.) gamae sp. nov. is very slender and elongated, with external edge basally sinuous, bearing smaller pair of basal teeth and of inner unpaired tooth. Unguiculus is slender and pointed with small outer tooth at 30% from its base. Unguis and unguiculus of H. (V.) absoloni are less elongated that those of the Catalan population, being intermediate with those of H. (H.) nitidus . The ratio body+head:inner edge of claw clearly illustrates these differences: about 45 for H. (V.) nitidus , about 37 for H. (V.) absoloni , and about 20 for H. (V.) gamae sp. nov.

Furca. The manubrium of H. (V.) gamae sp. nov. is dorsally beset only with serrated mes, without interspersed smooth pointed mac as in the population of H. (V.) absoloni .

Figures

FIGURES 50 – 53. Semi-diagrammatic macrochaetotaxy: 50, Heteromurus (Heteromurus) nitidus from Golubina pećina; 51, Heteromurus (Verhoeffiella) “ absoloni ” from Forat del Rastre as given by Gama (1984); 52, Heteromurus (Verhoeffiella) gamae sp. nov., our observation, pm-posteromedial mac; 53, Heteromurus (Verhoeffiella) absoloni, type population.

FIGURES 54 – 59. Heteromurus (Heteromurus) nitidus from Golubina pećina (54, 57), Heteromurus (Verhoeffiella) gamae sp. nov. (55, 58), Heteromurus (Verhoeffiella) absoloni from type locality (56, 59): 54 – 56, labial triangle chaetotaxy; 57 – 59, claw of leg III. Scales: 20 µm.