Lepidocyrtus flexicollis Gisin, 1965

Mateos, Eduardo, 2008, The European Lepidocyrtus Bourlet, 1839 (Collembola: Entomobryidae), Zootaxa 1769 (1), pp. 35-59 : 38-47

Lepidocyrtus flexicollis Gisin, 1965

Figs 1–12 , Tabs 2–3

Redescription. Adults body length (without head nor furca) 1.4–3.4 mm. White body, with dark blue pigment on anterior region of the head, ant.II–IV, and cx.I–II. Dark pigmented ocular areas. When alive the whole animal is silvering due to light refraction on the scales covering all the cuticle. Mesothorax strongly projecting over the head, so the head arranges forming a right angle with the body during the animal rest ( Fig. 1 ).

Antenna:cephalic diagonal between 1.97 and 2.3. Relation ant.I:II:III:IV such as 1:2:2:3. With scales on ant.I–III and ant.IV base. Basis of ant.I dorsally with three microchaetae arranged in triangle. Without apical ant.IV bulb.

Smooth prelabral and labral setae in typical number 4/5,5,4. One specimen (from Sinarcas, Valencia, see Table 2) has three ciliated and one smooth prelabral setae; another specimen (same locality) has one ciliated and three smooth prelabral setae. The four labral setae of the third row are shorter, more curved, and with more developed insertion than setae of the other two rows ( Fig. 2 ). Inverted V-shaped labral apical intrusion. All four labral papillae with blunt apex. Maxillary palps with two smooth macrochaetae.

Labium anterior row (a1–a5) formed by smooth macrochaetae; posterior row formed by ciliated macrochaetae (M 1 * M 2 R* E L 1 L 2), with M 1 and R smaller than the other setae (marked with *) ( Fig. 3 ). Ventral cephalic groove with 4+4 ciliated macrochaetae and 4+4 or 5+5 scales; several specimens with asymmetric number of scales (4+5).

The dorsal macrochaetae formula is R 0 R 1 So/00/0101+3. Maximum number of R setae between ocular areas 18+18 ( Fig. 4 ). Interocular chaetotaxy ( Fig. 5 ) with s, t, p ciliated setae, and 1–2 scales. Abd.II–III chaetotaxy as in Figs 6–7 . Abd.II medial pseudoporus is separated from trichobothrium m2 the length of one fanshaped seta. Abd.IV chaetotaxy as in Fig. 8 . Abd.IV trichobothrium T2 with accesory fan-shaped seta s. Abd.IV dorsal macrochaetae of two distinct morphologies: B4, B5, B6, C1, D3, E2, E3, E4, F1, F2, F3 broader and with broad insertion; T6, T7, D2, De3, E1, E4p, Fe4, Fe5 shorter or longer but always thinner and with insertion of minor diameter.

Legs with scales except in claws. Coxae dorsal surface with constant pattern of macrochaetae and pseudopori ( Fig. 9 ): cx.I with 14 smooth macrochaetae and 2 pseudopori; cx.II with 2 rows of smoot macrochaetae (of 11 and 13 macrochaetae respectively) and 4 pseudopori; cx.III with 18 smooth macrochaetae and 2 pseudopori. Trochanteral organ with 26–29 smooth straight setae arranged in rectangular shape ( Fig. 10 ). Unguis with basal pair teeth at 59% of the inner edge, and with two inner teeth at 79% (the bigger) and 89% of the inner edge respectively. Unguiculus lanceolate with finely serrate outer margin. Spatulate tibiotarsal tenent hair ( Fig. 11 ).

Furca with scales on dorsal and ventral surfaces. Manubrium:dens:mucro 25:23:1. Manubrial plate with 3 inner setae and 8–10 external setae, but with high inter- and intraindividual variability ( Fig. 12 ).

Distribution. Till now L. fexicollis was considered endemic of the Canary Islands (Tenerife and Hierro Islands, see Izquierdo et al. 2004). With the present data (Table 2), its distribution is extended to La Palma Island (the Canary Islands) and to mainland Spain.

Similar species. The currently published descriptions do not allow clear differentiation among the species L. curvicollis , L. flexicollis , L. montseniensis and L. nigrescens , due to shortcomings and errors in some of them. Several authors have described characters of L. curvicollis (see Table 1), but none of them described the interocular chaetotaxy, manubrial plate neither trocanteral organ. The original description of L. flexicollis is very succinct and has an error because it omits abd.II m3 macrochaeta ( Gisin 1965: Fig. 1 ); the original description of L. montseniensis does not describe the whole chaetotaxy of abd.II–IV nor interocular chaetot- axy neither trocanteral organ (see Mateos 1985); in the original description of L. nigrescens the abd.III–IV chaetotaxy is incomplete (see Szeptycki 1967).

The examined specimens of L. curvicollis , L. montseniensis and L. nigrescens show the same labial chaetotaxy ( Fig. 3 ), dorsal cephalic macrochaetae ( Fig. 4 ), and abd.III chaetotaxy ( Fig. 7 ) described for L. flexicollis ; L. montseniensis and L. nigrescens show also the same abd.II chaetotaxy described for L. flexicollis ( Fig. 6 ). The characters that distinguish the four mentioned species are the interocular chaetotaxy ( Figs 5 and 13 ), abd.II chaetotaxy ( Figs 6 and 14 ), abd.IV chaetotaxy ( Figs 8 , 15, 16, 17 ), prelabral setae (Table 5), trochanteral organ (Table 9), and manubrial plate (Table 5).

The abd.IV total chaetotaxy is very informative and shows differential characters for the four studied species, but not all setae are equally useful for the species diagnosis. Thus, among the examined specimens of the four species, setae D3p, De3, E4p, F3p, and Fe5 (see Fig. 8 ) show intraspecific variability and some specimens have them as smooth mesochaetae and some as thin ciliated macrochaetae. On the other hand, the number of smooth mesochaetae placed on A1–A3–B1–B2 area show intraspecific variability too, so they are not useful for specific differentiation. Other abd.IV setae have a morphology and relative position very constant for each species, so they are useful in the specific diagnosis. Table 3 summarizes the main differences in abd.IV chaetotaxic characters among the four species.

Figures

FIGURE 8. L. flexicollis: abd.IV complete chaetotaxy, broad black circles = broad ciliated macrochatae, small black circles = thin ciliated macrochaetae, white filled circles = smooth mesochaetae, triangles = fan-shaped setae, lines = microchaetae, x = trichobothria, # = pseudoporus.

FIGURES 1–3. L. flexicollis: 1, habitus; 2, labrum; 3, labium (left side) and ventral cephalic groove.

FIGURES 4–5. L. flexicollis: 4, dorsal head chaetotaxy, broad circles = long ciliated macrochatae, small circles = short ciliated macrochaetae, lines = smooth mesochetae; 5, interocular chaetotaxy (right ocular area).

FIGURES 6–7. L. flexicollis: 6, abd.II complete chaetotaxy, broad circles = broad ciliated macrochatae, lines = mesochetae, pse = pseudoporus; 7, abd.III complete chaetotaxy, broad circles = broad ciliated macrochatae, small circles = thin ciliated macrochaetae, lines = mesochetae, pse = pseudoporus.

FIGURES 9–12. L. flexicollis: 9, coxae, circles = macrochaetae, # = pseudopori; 10, trochanteral organ (two different specimens); 11, p-III unguis and unguiculus; 12, manubrial plate (two different specimens), circles = macrochaetae, filled circles = pseudopori.

FIGURES 13–14. L. curvicollis: 13, interocular chaetotaxy (right ocular area); 14, abd. II complete chaetotaxy (left side), same simbols as in Fig. 6, arrows indicate differences with respect to Fig. 6.

FIGURES 15–17. Abd.IV complete chaetotaxy (same symbols as in Fig. 8): 15, L. curvicollis; 16, L. montseniensis; 17, L. nigrescens.