Distinctive Collembola Communities in the Mesovoid Shallow Substratum: Entomobryomorpha of the Sierra de Guadarrama National Park (Central Spain) Author Baquero, Enrique University of Navarra, Faculty of Sciences, Department of Environmental Biology, University Campus, 31080, Pamplona (Spain) ebaquero@unav.es Author Jordana, Rafael University of Navarra, Faculty of Sciences, Department of Environmental Biology, University Campus, 31080, Pamplona (Spain) rjordana@unav.es Author Ortuño, Vicente M. Grupo de Investigación de Biología del Suelo y de los Ecosistemas Subterráneos, Departamento de Ciencias de la Vida, Facultad de Ciencias, Universidad de Alcalá, E- 28871, Alcalá de Henares, Madrid (Spain) vicente. ortuno @ uah. es vicente.ortuno@uah.es text Zoosystema 2021 2021-01-26 43 3 37 78 journal article 8557 10.5252/zoosystema2021v43a3 cd89b152-32bd-42cc-be33-a74a856fb5e4 1638-9387 4487162 urn:lsid:zoobank.org:pub:EA621D7C-F9AE-460B-8EBF-9E932862D4FE Pachyotoma penalarensis Baquero & Jordana n. sp. ( Figs 6A ; 7 ; Table 2 ) urn:lsid:zoobank.org:act: 5B96D956-8536-47F4-9842-6ADBF9BF3892 TYPE MATERIAL. — Holotype . Spain • ♀ ; Segovia , Sierra de Guadarrama , Majada Aranguez (Northwest); 30T 4190 45231; 2071 m a.s.l. ; 17.XI.2015 ; Ortuño et al. leg.; pitfall SSD (since 20.V.2015 ); MZNA SSD-8 (slide 16). Paratypes . Spain • 2 ♀ and 1 ♂ ; slide 16; same data as for holotype; MZNA • 1 ♂ (subadult) and 1 ♀ ; slide 02; same data as for holotype; MZNA • 11 juveniles on slide and approximately 500 in ethyl alcohol; slide 13; same data as for holotype; MZNA • 10 specimens in ethyl alcohol; Segovia , Sierra de Guadarrama , Majada Aranguez (Northwest); 30 T 4190 45231; 2071 m a.s.l. ; 17.XI.2015 ; Ortuño et al. leg.; pitfall SSD (since 20.V.2015 ); MNHN . FIG. 6. — Pachyotoma penalarensis Baquero & Jordana n. sp. : A , head chaetotaxy; B , antenna, with detail of organite ( C ); D , maxillary palp; E , tibiotarsus, claw and empodium of leg 3; F , furcula, left – anterior side, right – posterior side; G , tenaculum. Scale bars: A, B, E, F, 0.02 mm; D, G, 0.01 mm. TABLE 2.— Group of characters traditionally used for the identification of the species of the Proisotominae Stach, 1947 s.l. , and to establish some of the proposed subfamilies, for the species that share with Pachyotoma penalarensis Baquero & Jordana n. sp. (in combination) the number of eyes, the absence of tenent hair and a similar shape for the PAO, that are: Ballistura excavata Folsom, 1937 (N America; Africa), Clavisotoma africana (Womersley,1934) (South Africa), Clavisotoma fatonei (Rapoport, 1959) (Neotropical) , Clavisotoma filifera (Denis, 1931) (Europe, Neotropical), Ballistura laticauda Folsom, 1937 (as Clavisotoma in Bellinger et al. 1996 -2019) (USA, Azores), Coloburella cassagnaui Rusek, 1972 (Europe) , Coloburella linnaniemii (Denis, 1926) (Europe) , Folsomides centralis (Denis, 1931) (Costa Rica), Folsomides deflexus (Schött, 1927) (Cameroon) , Folsomides delamarei Thibaud, Najt & Jaquemart, 1994 (Galápagos) , Folsomides denisi (Womersley, 1935) (Australia) , Folsomides deserticolus Wood, 1970 (Australia) , Folsomides nepalicus Yosii, 1971 (Nepal) , Pachyotoma pseudorecta (Haybach, 1972) (Europe) , Proisotoma andina Rapoport & Rubio, 1968 (Neotropical) , Proisotoma beta Christiansen & Bellinger, 1980 (Neotropical) , Proisotoma muscicola Stach, 1965 (South East Asia), Proisotoma santosorum PalaciosVargas & Arbea, 2009 (Caribe) and Weberacantha beckeri Stebaeva, 1966 (Russia) . Legend for the headers of the columns: Head : EYE , eye number; PAO , form: b, broad;e, elliptical;l, long lobulated; i, long with central indentation; o, oval (almost circular),q, four lobes; PE , PAO/eye ratio. Legs: CL , claw tooth:0, absent; 1, present. Furca: ETF , empodial terminal filament:0, absent; 1, short; 2, long (as claw); MA , anterior manubrium chaetae number; MP , posterior manubrium chaetae number; DA , anterior dens chaetae number; DP , posterior dens chaetae number; TT , tenaculum teeth number; TC , tenaculum chaetae number; MT , mucro teeth number and shape: 9, absent; 8, fused to dens; 0, no dentate; 1, unidentate or falcate; 2, bidentate; 3, tridentate; 4, quadridentate. General abbreviations: n , numerous, U , unknown.

Subfamily	species	EYE	PAO PE		CL	ETF	MA	MP	DA	DP	TT	TC	MT
Proisotominae	B. excavata	6+ 6	e	1.2-1.5	0	1	0	U	1-5	12	4 + 4	1	2
Proisotominae	Cl. africana	6+ 6	o	1.2	1	1	U	U	1	12	3 + 3	U	2
Proisotominae	Cl. fatonei	6+ 6	e	1.5-2	1	0	0	n	1	13-15	4 + 4	1	2
Proisotominae	Cl. filifera	6+ 6	e	1.5	1	2	0	U	2-3	16-17	4 + 4	1	2
Proisotominae	Cl. laticauda	6 +6	o	2.5-3	1	2	0	U	2-3	9-15	3 + 3-4 +4 1		2
Pachyotominae	C. cassagnaui	5 + 5-6 +6	e	2.0	0	0	0	11 + 11	1	4	4 +4	1	8
Pachyotominae	C. linnaniemii	6+ 6	e	2.0	0	0	0	26-30	4	6	4 + 4	1	8
Proisotominae	F. centralis	6+ 6	e	U	0	1	0	22	2-3	6-7	4 + 4	1	2
Proisotominae	F. deflexus	6+ 6	o	3	0	1	U	U	U	U	4 + 4	1	2
Proisotominae	F. delamarei	6+ 6	e	2	0	2	0	12	1	3	3 + 3	1	2
Proisotominae	F. denisi	6 +6	o	2-3	0	0	0	6 +6	0	3	3 + 3	1	9
Proisotominae	F. deserticolus	6 +6	e	4	0	1	0	16	1	6	3 + 3	1	2
Proisotominae	F. nepalicus	6 +6	b	2	0	1	0	12	0	2	3 + 3	1	2
Pachyotominae	P. pseudorecta	6 +6	e	1.7	0	0	4	U	40	30	4 + 4	1	0
Pachyotominae	P. penalarensis Baquero & 6 + 6 Jordana n. sp.		q	2.0	0	0	0	30	4	9	4 +4	0	2
Proisotominae	Pr. andina	6+ 6	e	1.1	0	U	2	64	10	5	4 + 4	5	4
Proisotominae	Pr. beta	6+ 6	b	1	1	0	3	U	23-26	8-9	4 + 4	2-3 3
Proisotominae	Pr. muscicola	6+ 6	e	4	0	0	0	12	1	5	4 + 4	1	2
Proisotominae	Pr. santosorum	6+ 6	o	2.5-3.0	0	U	2	24-26	6	5	3 + 3	1	3
Proisotominae	W. beckeri	6 +6	i	U	1	U	4	18	2	5	4 + 4	1	2

TYPE LOCALITY. — Spain , Segovia, Sierra de Guadarrama, Majada Aranguez (Northwest); 30T 4190 45231; 2071 m a.s.l. ETYMOLOGY. — The specific epithet ‘penalarensis’ refers to the presence of this species in the Peñalara massif, which boasts the highest peak of the Sierra de Guadarrama. DIAGNOSIS. — Cylindrical dens, mucro present and bidentate, PAO with four lobes, Ant III sensory organ with the two central sensilla more or less spherical and number of sensilla on tergites at about 10,10/6,6,6,9,7. DESCRIPTION Body Size 0.72-0.80. Color dark blue. Integument granulated without reticulation. 6+ 6 to 8+ 8 eyes (sometimes eyes G and H disappear, but it is possible to see the refringent structures below). PAO with four lobes, two times eye A ( Fig. 6A ). Antenna as in Figure 6B, C ; AntIII sensory organ with the central sensilla more or less spherical; Ant IV with seven sensilla, six dorsoexternal and one dorsointernal. Maxillary outer lobe bifurcated and four sublobal hairs ( Fig. 6D ). Labral formula 4/5,5,4 (labral chaetae papillated). Labium with four basomedial, three proximal and five basolateral chaetae and, as common for the family, with 16 guard chaetae. Legs Tibiotarsus tenent hairs all pointed. Claw without tooth; empodium short with lamella but without terminal filament ( Fig. 6E ). Abdomen Collophore with 5+5 (or 6+6) laterodistal, and five posterior chaetae. Furca: manubrium with 28-30 posterior and without anterior chaetae; dens with nine posterior (three groups: three basal, two medial and four distal) and four distal anterior chaetae; mucro with two poorly developed teeth, and two lamellae ( Fig. 6F ). Tenaculum with four teeth and without chaeta on corpus ( Fig. 6G ). Chaetotaxy Body chaetae short and without macrochaetae (see Figure 7 for number of rows and axial chaetae). Thoracic medial schaetae in front of p-row; abdominal medial s-chaetae in p-row (AbdIV-V with three and four respectively additional ones before p-row); s-chaetae formula ( c. 10,10/6,6,6,9,7 for half tergite). Ms-chaetae formula 1,0/0,0,0 ( Fig. 7 ). ECOLOGY So far, this species has only been located in the MSS of the northern slope of the Peñalara massif, in SSD-8, installed in the Canchal de la Majada Aranguez ( Figs 1A, C ; 3A, B ). This site is located at altitudes that exceed 2000 m a.s.l., and is part of the supraforestal strip of the oro-Mediterranean bioclimatic zone. Extensive slopes dominate the landscape with a moderate slope, where there is very little vegetation, highlighting small stands of Juniperus communis alpina (Suter) Celak. ( Fig. 3A ). Pachyotoma penalarensis Baquero & Jordana n. sp. share their habitat with at least four other Collembola species, of which three are also new ( Figs 1F ; 3B ). As a whole, the syntopy of the five species at this site has provided an average relative activity that does not reach a thousand specimens ( Fig. 1E ). This species only represents 2% of the total Entomobryomorpha studied in this paper ( Fig.1D ), but accounts for 65% of the total Isotomidae collected ( Fig. 2A, C ). REMARKS Considering the group of characters for the family, the 6 + 6 ocelli and a very specific PAO are enough to establish the specimens found as a new species, assigned to the Pachyotominae subfamily due to the absence of anal spines, the presence of furca, fewer than four chaetae in the anterior part of the manubrium, granulation of the body, abundant sensory chaetotaxy, dens with teeth and absence of Mc. The new species really has an extraordinary shape of PAO compared with congeners and Isotomidae as a whole. The characters that are used for the separation of the different genera of the Proisotominae s.l. seem to have a low diagnostic value. It is probable that all this taxonomy is artificial and it will take further work to update definitions of the genera and probably also the subfamilies of all Isotomidae . The separation of the specimens of this sampling into a new species according to the number of eyes, PAO and presence or not of the tenent hair on the tibiotarsus can be seen in Table 2 , which includes the eye number, PAO shape, PAO/eye ratio, empodial terminal filament presence and shape, anterior manubrium chaetae number, posterior manubrium chaetae number, anterior dens chaetae number, posterior dens chaetae number, tenaculum teeth number, tenaculum chaetae number and mucro teeth number and shape. This table is an example of the absence of differential generic characters for the subfamily Proisotominae s.l .