Pygmarrhopalites sietae Baquero & Jordana, 2024

Baquero, Enrique, Jordana, Rafael & Fadrique, Floren, 2024, Two new species of Collembola (Arthropoda, Hexapoda) from Cova Urbana, a cave under a city, Subterranean Biology 49, pp. 163-184 : 163-184

Pygmarrhopalites sietae Baquero & Jordana sp. nov.

Figs 9 , 10 , 11 , 12 , 13 , 14

Type material.

Holotype • female on slide, Spain: Tarragona city, Tarragona province, Cova Urbana , geographic coordinates 41.114193, 1.248222, 15 m a. s. l. (the entrance is in an urban area), 6 / vii / 2022, dark zone of the cave, by aspirator ( MZNA code 782954 ) . Paratypes • same data as holotype, three specimens on slide ( MZNA codes 782955 and 782986 ), and one mounted on stub for SEM observation ( MZNA code 782953 ) . All Floren Fadrique leg ( BIOSP, Associació Catalana de Biospeleologia). Specimens deposited in MZNA.

Description.

Female. Body not pigmented; length (holotype): head, 0.23 mm; body 0.62 mm.

Head. Eyes 1 + 1, unpigmented. Clypeal area, row a: 2 + 2 and an axial chaeta; row b: 2 + 2; row c: 2 + 2; row d: 4 + 4; row e: 5 + 5; row f: 4 + 4. Inter-antennal area, row α: 2 + 2; row β: 1 + 1 and an axial chaeta; rows A and C: 2 + 2 and an axial chaeta; row B: 1 + 1 and an axial chaeta; row D: 2 + 2 chaeta. Lateral chaetae of rows C and D are not spine-like (Fig. 9 A ). Chaetotaxy of the mouth region. Labrum: pre-labral / labral chaetotaxy: 6 / 554. 2 + 2 chaetae near the ventral groove. Maxilla: apical chaeta of the maxillary outer lobe with a short and thin subparallel branch at the base; sublobal plate with three sublobal hairs.

Antenna (Fig. 9 B – D ): I / II / III / IV, 0.030 / 0.058 / 0.106 / 0.090-0.032 - 0.32 - 0.030 - 0.070; shorter than the body (ratio 0.72) and ratio Ant / head as 1.95; basal subsegment of Ant IV 0.84 times longer than Ant III. Ant I with seven chaetae, any as mic. Ant II with 15 chaetae, two interior ones longer than others (16 because an additional one in the second whorl on one antenna of one specimen). Ant III with a conspicuous papilla, 15 chaetae, the two sense rods, and two thin setae and one short lateral sensilla; Ant IV with five distinct subsegments, with four evident whorls: one at the end of the first and three on the second to fourth subsegments. Apical subsegment with knobbed subapical organite; one of the chaetae on this area has a narrowing since the terminal half.

Legs. (Figs 10 A – F , 11 ): Foreleg pre-coxae 1, 2, and coxa with 1, 0, 1 chaetae respectively. Trochanter with three anterior and one posterior chaetae. Femur with 11 chaetae, a 4 turned perpendicularly to the longitudinal axis of the segment. Tibiotarsus: whorl I with nine chaetae among which Ja curved and somewhat thickened, II – V with 8, 8, 8, and 7 chaetae respectively; region F with three primary FP chaetae (e, ae, pe) and secondary chaeta FSa. Pre-tarsus with one anterior and one posterior chaetae. Foot complex: claw thin, without tunica evident, with inner tooth and two pairs of indistinct lateral teeth (25 and 60 % from claw basis); empodium thin, with corner tooth (Fig. 11 ), and long apical filament surpassing the tip of the claw. Mid leg pre-coxae 1 and 2 with 1, 1 chaetae respectively, pre-coxal process present, coxa with two chaetae and a microsensillum. Trochanter with three chaetae and a trochanteral organ. Femur with 14 chaetae, p 1 and p 3 very small. Tibiotarsus: whorl I with nine chaetae, whorls II – V with 8, 8, 8, and 7 chaetae respectively; region F with three FP chaetae and FSa chaeta. Foot complex: claw wider than foreleg claw, with tunica not evident, inner tooth, and two pairs of small lateral teeth; empodium without corner tooth but with a long apical filament surpassing the tip of the claw. Hind leg pre-coxae 1 and 2 with 1, 1 chaetae respectively, process on pre-coxa 1 present, coxa with three chaetae and a microsensillum. Trochanter with three chaetae and a trochanteral organ. Femur with 13 chaetae, p 1 and p 3 as mic. Tibiotarsus: whorl I with nine chaetae, whorls II – V with 8, 8, 8, and 7 chaetae respectively; region F with three FP chaetae and FSa chaeta. Foot complex: claw wider than foreleg claw, with tunica not evident, inner tooth, and two pairs of small lateral teeth; empodium without tooth, and a short apical filament.

Great abdomen (Fig. 12 A ): Th II with a sensillum in row a, and three chaetae in row m (m 1 bigger, thickened at the base). Th III with a sensillum in row a and three chaetae in row m. Abd I row a with five chaetae, row m with four, and four p chaetae, above bothriotrichal complex. Bothriotrichal complex: ABC almost linear; bothriotrichum A with one posterior accessory short chaeta; bothriotrichum B with one posterior accessory short chaeta; bothriotrichum C with two anterior accessory short chaetae. Posterior lateral complex with 4 + 3 chaetae. Posterior dorsal complex with three rows with 8, 10, and 9 long chaetae each.

Abd VI. Sixth abdominal segment: a 0 not bifurcate, and none of the other circum-anal chaetae broadened, winged or serrated; anal appendage with long fringes or brush-like along final two thirds (Fig. 12 B ).

Ventral tube with 1 + 1 subapical chaetae.

Tenaculum with two apical chaetae on the corpus, three teeth, and a basal process on each ramus (Fig. 12 C ). Furca (Fig. 13 A, B ): manubrium with 4 + 4 posterior chaetae. Dens: anterior side with 3, 2, 1, 1 chaetae; externally Ie as massive spine, and IIpe as a big spine-like chaeta; internally Ii, IIIpi and IVpi moderately spinous, but with alveoli (Fig. 14 A ). Mucro: both lamellae serrated forming a channel at the end. Dens about 1.4 × as long as mucro (Fig. 14 B ).

Ecology.

The specimens were only captured near the main siphon of the Maginet Room (Fig. 2 ).

Etymology.

The name of the new species is dedicated to the association that maintains the cavity and organizes the visits, the Societat d’Investigacions Espeleològiques de Tarragona ( SIET).

Remarks.

There are only two previously described species that share the presence of only one eye, absence of spine-like chaetae on posterior head, presence of papilla on Ant III, the number and position of spines / spine-like on dens (203 for external / anterior / internal) and a similar shape of anal appendage: P. furcatus ( Stach, 1945) and P. ornatus ( Stach, 1945). P. furcatus has not tooth on the claw of leg 1, a long filament on empodium of leg 3, and the anal appendice simply bifurcate; P. ornatus has not tooth on empodium of leg 1 and the filament on empodium of leg 3 is longer than in the new species; both species have the proximal spine (IIpe) on external dens strong and articulate, while in the new species is only a spine-like chaeta. The three descriptions of P. ornatus ( Stach 1945; Cassagnau-Debouteville 1953; Dallai 1972) do not coincide with each other; Cassagnau-Delamare and Dallai say that their specimens coincide with the original description, but in the first case the anal appendage is branched, and in the second case the circumanal chaetae are broadened (in Stach one of the three drawings of the appendage is shown branched and the circumanal chaetae are not thickened). Bretfeld (1999) says that none of the post-Stach descriptions have consulted types (we haven’t either). In future, if more specimens ar found in this cave, this species should be compared with the types of P. ornatus, since they are very similar.

Figures

Figure 2. Original diagram of the topography of Cova Urbana elaborated by the Societat d’Investigacions Espeleològiques de Tarragona team.

Figure 9. Pygmarrhopalites sietae sp. nov. A head chaetotaxy B Ant I – II (* means that this chaeta has been observed only in one specimen) C Ant III (the arrows point to chaetae that are noticeably thinner than the others and the sensory organ are included in a rectangle with the chaetae in black) Ant IV (the arrow points to the knobbed subapical organite). Scale bar: 0.05 mm.

Figure 10. Pygmarrhopalites sietae sp. nov. A – C precoxa 1–2 and coxa of legs 1 to 3 respectively D – F tibiotarsi, claw and empodium of legs 1 to 3. Scale bar: 0.05 mm.

Figure 11. Pygmarrhopalites sietae sp. nov. Claw and empodium of leg 1. Scale bar: 0.001 mm.

Figure 12. Pygmarrhopalites sietae sp. nov. A great abdomen, with detail of the shape of some chaetae B two some different morphologies of the anal appendage C tenaculum. Scale bars: 0.05 mm and 0.001 mm for detail of the chaetae (A); 0.005 mm (B).

Figure 13. Pygmarrhopalites sietae sp. nov.: furcal complex, with detail of some spine-like chaetae. Scale bar: 0.05 mm.

Figure 14. Pygmarrhopalites sietae sp. nov. A distal area of dentes, external view B mucro, external view. Scale bars: 0.001 mm.