Pseudosinella altamirensis, Baquero & Jordana & Labrada & Luque, 2020

Baquero, Enrique, Jordana, Rafael, Labrada, Lucia & Luque, Carlos G., 2020, A new species of Pseudosinella Schaeffer, 1897 (Collembola, Entomobryidae) from Altamira Caves (Cantabria, Spain), ZooKeys 989, pp. 39-54 : 39

Pseudosinella altamirensis sp. nov. Figs 3 , 4 , 5 , 6 , 7

Type material.

Holotype: Spain • ♀; Cantabria, municipal district of Santillana del Mar, Altamira Cave, Sala de Polícromos (Polychromes Room), National Museum and Research Centre of Altamira; 43°22.61'N, 4°7.18'W; 148 m a.s.l.; 29 Aug. 2000; C. Glez.-Luque leg.; slide labelled " MZNA -Altamira 6d-01". Paratypes: • 49 specimens on ethyl alcohol and 3 specimens mounted on SEM stubs; Cueva de las Estalactitas (Stalactites cave); 43°22.64'N, 4°7.21'W; 148 m a.s.l.; 29 Aug. 2000; C. Glez.-Luque leg.; slides MZNA -Altamira 6d-02 to 05 • 3 specimens on slides and 25 in ethyl alcohol; Polychromes Room; 43°22.61'N, 4°7.18'W; 148 m a.s.l.; 24 Mar. 2008; Cesáreo Saiz leg.; slides MZNA -Altamira01-01 and MZNA -Altamira01-02; deposited at the Museum of Zoology, University of Navarra, Pamplona, Spain (MZNA).

Other material.

Spain - Cantabria • 2 specimens on slides and 14 on ethyl alcohol; La Venta del Cuco cave, Ubiarco, Santillana del Mar; 43°24.28'N, 4°6.35'W; 145 m a.s.l.; 13 Sep. 1995; C. Glez.-Luque leg.; slides MZNA -Luque Coll. 13d-01 and 02 • 1 specimen on slide and 1 in ethyl alcohol; Cudón cave, Cudón, Miengo; 43°24.94'N, 4°0.74'W; 22 m a.s.l.; 14 Sep. 1995; C. Glez.-Luque leg.; slide MZNA -Luque Coll. 36d • 1 specimen on slide and 3 in ethyl alcohol; Peña Caranceja or La Peñona cave, Barcenaciones, Reocín; 43°20.33'N, 4°9.45'W; 125 m a.s.l.; 7 Oct. 2000; C. Glez.-Luque leg.; slide MZNA -Luque Coll. 3d • 2 specimens on slide and three in ethyl alcohol; Cobezo, Cobeján or Perro cave, Viaña, Cabuérniga; 43°11.61'N, 4°16.52'W; 360 m a.s.l.; 15 Jun. 1996; C. Glez.-Luque leg.; slide MZNA -Luque Coll. 7d.

Diagnosis.

5 + 5 ocelli. Antennae moderately long. Ant III sense organ with two paddle- or leaf-shaped and two additional sensilla. Area not ringed of dentes nearly five times the length of mucro. Claw elongate, with two paired basal teeth; tenent hair acuminate. Reduced formula: R0R1R2000/00/0101+2/s, -aBq1q2, M1m2R*el1l2 (* 1/3 to 2/3 of M; sometimes M1 smooth and L2 ciliated, and usually asymmetrically).

Description.

Habitus (Figs 3 , 4A ). Body length up to 3.1 mm (holotype: 2.3 mm). Colour: blue pigment laterally on body from Th II to Abd IV, but extended to dorsal part in Th II, coxae I-III, first third of femur III, laterally on head and vertex and Ant I-III. Abd IV paler. Eyes and a spot on central vertex strongly pigmented.

Head. With five eyes (ABDEF or ABCDF; C and F smaller, almost imperceptible in some specimens). Intraocular chaetae p, r, and s present. Only A0, A2, A3, An1, An2, An3a, and An3 as Mc (Fig. 7C ). Ratio antenna/cephalic diagonal 1.64-2.16. Antennal segments I/II/III/IV ratios 1/2-2.7/2.3-2.7/3.5-4.1. Ant IV proximal area in Fig. 5A ; apical vesicle absent (Fig. 7A ); in this segment there are up to four special leaf-shaped sensilla on the distal third, two of them aligned, and at least five other different types of sensilla (some described by Beruete et al. 2002): smooth and cylindrical, some with short fringes, clearly different from the normal chaetae (Fig. 5B ); smooth, shorter and narrowed in its distal third (Fig. 5C ); and leaf-shaped, similar to the sensorial chaetae ‘s’ of sensory organ of Ant III (Fig. 5D ). Ant III sense organ with a peculiar configuration: two paddle-shaped sensilla (individually encased in a pit and more or less one above the other), another two similar ones but in a dorso-internal position, and two small, rounded, spiny guard sensilla on both sides of the first one (Fig. 7B ). Apical region of the Ant II-III with pseudopore in internal-ventral position, far from chaetae line. Antennae without scales. Prelabral chaetae ciliated; labral row a, m, and p all smooth (distal row (a) on papillae). Formula of the labial base M1m2Rel1l2; M1 sometimes smooth, asymmetrical in some specimens; R ciliated, 1/3 to 1/2 length of the neighbouring smooth Mc m2; l1 occasionally ciliated; the remaining chaetae smooth, but with minute fringes or ciliation seen only in SEM (Fig. 5E ). Bifurcate maxillary palp with three smooth sublobal chaetae. Labial papilla (l.p.) E with finger-shaped process just reaching the base of apical appendage. Maxilla in Fig. 5F .

Body. Th II without Mc; pseudopore of this tergite in Fig. 6A . Th III without Mc. Abd II: chaetae a, q1 and q2 as ciliated mic, chaeta B as broad ciliated Mc (Fig. 7D ). Abd III chaetotaxy shown in Fig. 7E . Accessory chaeta ‘s’ in the anterior trichobothrial complex of Abd IV present. Medial chaeta B5 below the level of the trichobothrium T4. Pseudopore between B5 and B6. Legs scales only on coxae. Trochanteral organ with ca 30 chaetae (Fig. 4C ). Remaining chaetae clearly visible on all legs, acuminate and largest on leg III. Differentiated supraempodial inner chaeta on hind tibiotarsus well differentiated and acuminate. Dorsal tibiotarsal tenent hairs acuminate, 0.3 times the length of inner margin of claw. Claw with only three internal teeth: dental plate occupying 35% of the basal internal edge, with the basal paired teeth of different sizes (posterior one larger and slightly more distal than anterior); unpaired tooth well developed, approximately 40% from base; lateral tooth, anterior, less frequently posterior, present in some specimens on leg I and in basal positions; dorsal tooth basal, observed only in one specimen at SEM. Empodium appendage acuminate, basally swollen, externally smooth, with a minute tooth in some specimens (Figs 4B , 6B ). Retinaculum with 4 + 4 teeth and one ciliated chaeta. Ventral tube without scales; lateral flap with a maximum of eight smooth and six ciliated chaetae. Manubrium and dens with scales only ventrally (anteriorly); two internal and 7-12 external chaetae related to two distal pseudopores of manubrial plate; area not ringed of dentes nearly five times the length of mucro; mucro with distal tooth longer than the anteapical; basal spine reaching the tip of distal tooth (Fig. 6C-F ). Chaetotaxy from head to Abd V illustrated in Fig. 7C-G .

Biology.

This species is always found over organic matter accumulation. In Cudón cave, it has been found over the residue of rotten and wet wood; in the other caves it was found over old, mouldy rat and bat faeces and generally in insect cadavers with visible fungi. Although this species reaches to the dark zone of the caves near very wet areas, it has been found in deep zones on walls, roofs, and soils where the environmental humidity is near the saturation point (Fig. 2 ). The species appears to be restricted to the karst systems associated with the Saja River and within the municipal districts of Miengo, Santillana del Mar, Reocín, and Cabuérniga ( Luque and Labrada 2016) (Fig. 1 ).

Etymology.

The name is toponymical and refers to the type locality, the Altamira Cave, one of the most important Palaeolithic art sites in Europe.

Figures

Figure 1. Location of the studied area. A Cantabrian Mountains (northern Spain) B UTM grid map with 10 km squares of the central region of the Cantabrian Mountain to show the outcrops of the rock systems (in grey) which contain limestone and geographical situation of the study area with the distribution of the cave-dwelling Pseudosinella altamirensis sp. nov.: (1) Cudon cave; (2) La Venta del Cuco cave; (3) Altamira and Stalactites caves; (4) Pena Caranceja cave; (5) Cobezo cave. Source: Spanish Geological Institute and Cartographic Service of the Cantabrian Government, scale 1: 50 000.

Figure 2. Geographical location of Altamira Caves (Cantabria, Spain). A location and ground plan of the Altamira Caves and its museum B location of the Pseudosinella altamirensis sp. nov. sampling sites along Altamira Cave (August 2000): (1) areas where soil contained mouldy rat or bat faeces; (2) areas where soil contained a rat cadaver (Rattus rattus); (3) areas where soil contained a bat cadaver (Rhinolophus hipossideros); (4) areas where walls had insect cadavers with visible fungal; (5) areas where water drips or flows towards the cave (hygropetric habitats); (6) areas where water had flooded the surface with small rim stone dams or gours; (7) areas with high clay soil content in the water; (8) areas of continuous monitoring of radon. Plan of the caves with its location courtesy of the National Museum and Research Centre of Altamira.

Figure 3. Pseudosinella altamirensis sp. nov. Habitus. Scale bar: 0.5 mm.

Figure 4. Pseudosinella altamirensis sp. nov. A habitus B distal part of tibiotarsus III and claw complex C trochanteral organ. Scale bars: 0.5 mm (A); 0.02 mm (B, C).

Figure 5. Pseudosinella altamirensis sp. nov. A proximal half of Ant IV B detail of Ant IV showing normal chaetae and different types of sensilla: leaf shaped, smooth, with small cilia C detail at high magnification of the small sensilla narrowed at tip found on Ant II-IV D two leaf-shaped sensilla on Ant IV E labium and labral palps F maxillae. Scale bars: 0.02 mm (A, E); 0.007 mm (B); 0.002 mm (C); 0.006 mm (D); 0.009 mm (F).

Figure 6. Pseudosinella altamirensis sp. nov. A Th II pseudopore B claw and empodium appendage of leg III C distal par of dens and mucro D tip of dens and mucro, not visible by the covering scales of terminal dens E mucro partially covered by scales and chaetae F mucro and mucronal spine. Scale bars: 0.004 mm (A, F); 0.02 mm (B, D); 0.04 mm (C); 0.007 mm (E).

Figure 7. Pseudosinella altamirensis sp. nov. A antennae, tip of Ant IV B antennae, Ant III sensory organ C head, dorsal chaetotaxy; Abdomen dorsal chaetotaxy: D abd II E abd III F abd IV G abd V. White dots, Mc (size of the socket proportional to reality); black dots, mic. Scale bars: 0.01 mm (A); 0.02 mm (B); 0.05 mm (C-E); 0.1 mm (F, G).