Lepidocyrtus apicalis, Mateos, Eduardo & Petersen, Henning, 2012

Mateos, Eduardo & Petersen, Henning, 2012, Definition of the European Lepidocyrtus curvicollis group (Collembola: Entomobryidae) with description of a new species from Sardinia (Italy), Zootaxa 3273, pp. 51-62 : 53-59

Lepidocyrtus apicalis sp. nov.

Figs 1–19 , Tabs 1–2

Type material. Holotype: male in two slides ( CRBA 10157-a, CRBA 10157-b), nature reserve “Le Prigionette” in the peninsula of Capo Caccia, NW Sardinia, Italy (40o 36´N, 8o 9´E), soil surface in a firebreak strip of a relatively young pine woodland, vegetation dominated by sclerophyllous plants ( Helichrysum italicum , Cistus monspeliensis , Dorychnium pentaphyllum ), extracted from soil cores by high gradient extractors, 1.v.2003, leg. H. Petersen. Paratypes: two males, seven adults without visible sexual plate, four sub-adults, and five juvenile specimens on slides, the same data as the holotype. Holotype and one paratype (specimen CRBA 10158) saved in the collection of the Centre de Recursos de Biodiversitat Animal, Faculty of Biology, University of Barcelona (http:// www.crba.ub.edu); five paratypes kept at the Natural History Museum, Aarhus, Denmark (slide codes: L1/VUL- CAN-SA-ofl-D2-2-b, L2/VULCAN-SA-ofl-W2-3-c, L3/VULCAN-SA-S-D3-2-a, L4/VULCAN-SA-S-W2-4-b, L5/VULCAN-SA-S-W3-1-b); twelve paratypes kept in the E. Mateos’ collection (slide codes: LP293-1, LP293-2, LP293-3, LP293-4, LP293-5, LP293-6, LP293-7, LP293-12, LP293-16, LP293-21, LP293-22, LP293-23).

Other material. Same data as type material; 20 specimens preserved in alcohol and kept in the E. Mateos’ collection; Four specimens on slides and about 240 specimens mixed with other microarthropods preserved in glycerol are kept at the Mols Laboratory (Field Station of the Natural History Museum, Aarhus, Denmark). The Lepidocyrtus specimens stored in glycerol were not examined by high-power microscopy and include juveniles. Therefore, this material may contain specimens other than those belonging to the new species.

Etymology. The species name refers to the presence of the apical antennal bulb, which is a diagostic character for the new species within the L. curvicollis group.

Description. Adult body length (without head and furca) 1.3–2.2 mm. White-yellowish body, with dark blue pigment on the ventral region of the head, ant.II–IV (with increasing colour intensity towards the distal part of each segment), and cx.I–III; densely black pigmented ocular areas. The foremost part of the eye-patches connected by a pigmented band. Mesothorax projecting over the head ( Fig. 1 ).

Ratio antenna:cephalic diagonal 1.6–1.9. Ratio ant.I:II:III: IV 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. Ant.III organ composed of two subcylindrical and curved sensory rods dorsally covered by an integumentary fold ( Figs. 2 and 3 ). With apical ant.IV bulb ( Fig. 4 ).

Ciliated prelabral setae (one out of the 19 examined specimens with smooth prelabral setae) and smooth labral setae in typical number 4/5,5,4. Inverted U-shaped labral apical intrusion. Four rounded labral papillae, the two inner armed with a small spine, and the two outer smooth ( Fig. 5 ). Lateral process (sensu Fjellberg 1999) of outer labial papilla curved, tip not reaching the apex of the papilla ( Fig. 6 ). Maxillary palps with two lobal smooth setae ( Fig 7 ) and three sublobal smooth setae.

Labial anterior row formed by five smooth setae (a1–a5); posterior row formed by ciliated setae (M1*M2R*EL1L2), with M1 and R smaller than the other setae (marked with *) ( Fig. 8 ). Ventral cephalic groove with 4+4 ciliated setae ( Fig. 8 ).

Dorsal macrochaetae formula is R0 R1s R1So/00/0101+3 ( Fig. 9 ): a pair of supplementary macrochaetae R1s between R0 and R1 present ( Fig. 10 ). Maximum number of macrochaetae A between ocular areas 16+16 ( Fig. 10 ). Interocular chaetotaxy with ciliated setae (s, t, p), and one scale; eyes G and H reduced ( Fig. 11 ). Abd.II–III chaetotaxy as in Figs 12–13 . Abd.II seta p5p absent. Abd.IV chaetotaxy as in Fig. 14 ; trichobothrium T2 with accessory fan-shaped seta s ( Fig. 15 ); dorsal macrochaetae of two distinct morphologies: B4, B5, B6, C1, D3, E2, E3, E4, F1, F2, F3 broader and with broad socket; T6, T7, D2, De 3, E1, Fe4, Fe5 shorter or longer but always thinner and with socket of minor diameter; macrochaeta E3 inserted above F2; macrochaeta E4 inserted at the same level of F3 (the relative positions of macrochaeta on abd. IV, i.e. “above”/”same level”, refer to the orientation in Fig. 14 ).

Legs with scales except on claws. Trochanteral organ (leg III) with a maximum of 28 smooth straight setae arranged in rectangular shape ( Fig. 16 ). Unguis with basal pair of teeth at 50 % of the inner edge, and with two inner teeth at 68 % (the bigger) and 86 % from the base of the inner edge respectively. Unguiculus lanceolate with serrate outer margin. Spatulate tibiotarsal tenent hair ( Fig. 17 ).

Ventral tube with scales and with all setae ciliated both on anterior and posterior sides; each lateral flap with a maximum of 25 ciliated setae and 3 smooth setae (almost double in length than ciliated ones) ( Figs. 18 and 19 ).

Furca with scales on both dorsal and ventral surfaces. Ratio manubrium:dens:mucro as 19:19:1. Manubrial plate with two pseudopori, 3 inner setae, and a maximum of 12 external setae.

Ecology and distribution. The species has until now only been recorded in the type locality. The abundance in all treatments and strata together was estimated as 285 ± 101 m -2 (Standard Error) with highest abundance in the soil layer (240 ± 91 m -2). The largest number of specimens were collected in the suction samples from the soil surface. In that stratum the species made up 15.6 % of all Collembola .

Discussion. In the new species described, the presence of scales on antennae and legs, the labial chaetotaxy, the number of cephalic macrochaetae A, the number of setae on trocanteral organ of leg III, and the number of setae on the manubrial plate are variable characters depending on the size of specimen ( Table 1 ). Moreover, the chaetotaxy of the accessory setae of the dorsal trichobothria on abd.II–III–IV is incomplete in the specimens less than 0.8 mm of body length. On the other hand, the presence of ant.IV apical bulb, the ratio of distances between macrochaeta C1–4/B4–B6 on abd.IV, and the number and relative position of the dorsal macrochaetae are relatively stable characters that do not depend on the size of specimens. The only exception is the morphology of seta E1 of abd.IV, which is a smooth mesochaeta on specimens less than 1 mm of body length, appearing as ciliated macrochaeta in larger specimens ( Table 1 ).

The dorsal macrochaetae formula of the new species is the same as in the species L. curvicollis , L. flexicollis Gisin 1965 , L. mariani Traser & Danyi, 2008 , L. montseniensis Mateos, 1985 , L. nigrescens Szeptycki, 1967 , L. paradoxus and L. vexillosus Loksa & Bogojeviċ, 1967 . The new species differs from these by having ant.IV apical bulb. Other characters that distinguish L. apicalis sp. nov. from each of the above-mentioned species are specified in Table 2. Within the European Lepidocyrtus the apical antennal bulb is present only in the species L. fimetarius , L. lusitanicus , L. selvaticus Arbea & Ariza, 2007 , L. bilobatus Mateos, 2008 , and in several cavernicolous specimens of L. serbicus Denis, 1933 from Romania ( Gruia & Popa 2005). These five species are clearly differentiated from L. apicalis sp. nov. by many characters (see Mateos 2008a and 2008b for character lists of the above mentioned five species).

pigmentation; ocular q: presence (+) or absence (-) of interocular seta q; prelabral setae: morphology of prelabral setae, c––cil-

iated, s––smooth; labial M1-M2: relative size of labial setae M1 and M2; ant.IV bulb: presence (+) or absence (-) of antennal api-

cal bulb; abd.IV s: presence (+) or absence (-) of seta s on abd.IV in adult specimens; abd.IV T6: morphology of seta T6,

TcM––thin ciliated macrochaeta, sm––smooth mesochaeta; abd.IV pse: number of dorsolateral pseudopori between macro-

chaetae T6-D3-B5-B6 on abd.IV; abd.IV E3/F2: relative position between setae E3 and F2 on abd.IV (orientation as in Fig. 14 ),

up––E3 inserted above F2, dn––E3 inserted below F2; abd.IV E4/F3: relative position between setae E4 and F3 on abd.IV (ori-

entation as in Fig. 14 ), up––E4 inserted at the same level as F3, dn––E4 inserted below F3; C1–B4/B4–B6: ratio between

C1–B4 setae distance and B4–B6 setae distance on abd.IV. In all characters “?” denotes absence of published information. a Sensu Soto-Adames (2000); b Sensu Szeptycki (1967); c Sensu Gisin (1964a: Fig.1 ); d Sensu Loksa& Bogojevic (1967: Fig. 24)

Figures

FIGURE 1. Lepidocyrtus apicalis sp. nov.: 1, habitus.

FIGURES 2 – 4. Lepidocyrtus apicalis sp. nov.: 2, ant. III dorsal view showing ant. III organ, scale covering, and ciliated macrochaetae (circles); 3, lateral view of ant. III apex at ant. III organ level; 4, ant. IV apex.

FIGURES 5 – 9. Lepidocyrtus apicalis sp. nov.: 5, apex of labrum; 6, outer labial papilla; 7, maxilary palp; 8, labium (left side) and ventral cephalic groove; 9, dorsal macrochaetae (circles), trichobothria (lines) and pseudopori (#).

FIGURES 10 – 11. Lepidocyrtus apicalis sp. nov.: 10, dorsal head chaetotaxy, broad circles –– long ciliated macrochaetae, small circles—short ciliated macrochaetae, lines –– smooth mesochaetae; 11, interocular chaetotaxy (right ocular area).

FIGURES 12 – 13. Lepidocyrtus apicalis sp. nov.: 12, abd. II complete chaetotaxy, broad circles –– broad ciliated macrochaetae, lines—mesochaetae, pse –– pseudoporus; 13, abd. III complete chaetotaxy, broad circles –– broad ciliated macrochaetae, small circles—thin ciliated macrochaetae, lines –– mesochaetae, pse –– pseudoporus.

FIGURES 14 – 15. Lepidocyrtus apicalis sp. nov.: 14, abd. IV complete chaetotaxy, broad black circles –– broad ciliated macrochaetae, small black circles –– thin ciliated macrochaetae, lines –– smooth mesochaetae and microchaetae, triangles –– fanshaped setae, x –– trichobothria, # — pseudoporus; 15, abd. IV trichobothrial complex.

FIGURES 16 – 19. Lepidocyrtus apicalis sp. nov.: 16, trochanteral organ (other setae than trochanteral organ omitted); 17, third leg unguis and unguiculus; 18, ventral tube, anterior side (left half without scales, right half without setae); 19, ventral tube, left lateral flap.

Tables

TABLE 1. Lepidocyrtus apicalis sp. nov. Some characters of examined specimens: Long mm: body length in mm; ant. scales: presence (indicating segments with scales) or absence (-) of scales on antenna; head A: number of cephalic macrocheatae A; labium: labial chaetotaxy; leg scales: presence (+) or absence (-) of scales on legs; troc organ: setae number on trochanteral organ; man plate: setae number on manubrial plate; abd. IV E 1: morphology of seta E 1 on abd. IV, TcM –– thin ciliated macrochaeta, sm –– smooth mesochaeta; abd. IV s: presence (+) or absence (-) of seta s on abd. IV; abd. IV C 1 – B 4 / B 4 – B 6: Ratio between C 1 – B 4 setae distance and B 4 – B 6 setae distance on abd. IV. In all characters “? ” denotes that the character is not visible in the specimen.

Specimen code	Long mm	Ant scales	Head A	Labium	Leg scales	Troc organ	Man plate	Abd.IV E1	Abd.IV s	Abd.IV C1-B4/B4-B6
LP293-7	0.6	-	7	MELL	-	4	?	sm	-	0.56
LP293-12	0.7	-	8	MELL	-	?	?	sm	-	0.52
LP293-16	0.9	I–IV	9	MRELL	+	11	3+3	sm	-	0.48
L4	0.9	I–III	9	MMRELL	+	9	?	sm	-	0.52
L5	1.0	I–IV	9	MMRELL	+	11	3+4	sm	+	0.54
LP293-2	1.3	I–IV	12	MMRELL	+	16	3+8	TcM	+	0.51
CRBA10157	1.3	I–IV	12	MMRELL	+	15	3+9	TcM	+	0.48
CRBA10158	1.4	I–IV	12	MMRELL	+	?	3+8	TcM	+	0.49
L1	1.4	I–III	?	MMRELL	+	15	3+6	TcM	+	0.54
LP293-4	1.4	I–IV	14	MMRELL	+	16	3+6	TcM	+	0.51
L3 LP293-23	1.5 1.5	I–IV I–IV	? 15	MMRELL MMRELL	+ +	18 18	3+6 3+6	TcM TcM	+ +	0.46 0.56
LP293-3	1.6	I–IV	15	MMRELL	+	24	3+10	TcM	+	0.42
L2	1.7	I–IV	?	MMRELL	+	?	3+11	TcM	+	0.54
LP293-1	1.7	I–IV	15	MMRELL	+	25	3+12	TcM	+	0.54
LP293-5	1.8	I–IV	15	MMRELL	+	26	?	TcM	+	0.52
LP293-22	1.9	I–IV	15	MMRELL	+	28	3+9	TcM	+	0.52
LP293-21	2.0	I–IV	15	MMRELL	+	25	3+12	TcM	+	0.49
LP293-6	2.2	I–IV	16	MMRELL	+	25	3+12	TcM	+	0.40