Alloscopus arborealis Alviola & Lucañas & Lit & Soto-Adames & Jantarit 2024, sp. nov.
Creators: name: Alviola, Marnelli S.
name: Lucañas, Cristian C.
name: Lit, Ireneo L.
name: Soto-Adames, Felipe N.
name: Jantarit, Sopark
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Collembola
Entomobryomorpha
Orchesellidae
Alloscopus
Alloscopus arborealis

description: Alloscopus arborealis sp. nov. Alviola, Lucañas & Jantarit
Figs 1D, 2–5, Table 1
Material examined. HOLOTYPE male: Philippines: Laguna, Mt. Makiling, lower montane forest, N 14°8’27.96”, E 121°12’5.33”, 619 m asl., on suspended canopy soil in Dillenia philippinensis, 16.viii.2018 (M. S. Alviola leg., UPLB MNH COLL-00299). PARATYPES: same data of the holotype, except for Mahogany plantation ex. Forest floor leaf litter, 17.vii.2018 (UPLB MNH COLL-00300 ♂; FSCA 1 ♀; THA 2 subadult ♀); Mahogany plantation, on Swietenia macrophylla canopy, 31.viii.2018 (UPLB MNH COLL-00302 ♀, 00303 ♀); dipterocarp plantation, on Forest floor leaf litter, 27.ix.2018 (UPLB MNH COLL-00301 ♂; THA 1♀), 31.vii.2018 (FSCA 2♀).
Description. Habitus (Fig. 1D). Medium size Orchesellidae. Body length (head+trunk) up to 1.51 mm (holotype 0.91 mm). Females (average size 1.43 mm) larger than the males (average size 0.89 mm). Scales present on both sides of Ant. I–II, both sides of head, dorsal trunk, legs (coxa to femur), posterior ventral tube, and both sides of manubrium and dens. Color: whitish, body without any pigment. Ocular patches absent. Antennae shorter than the body. Body slender, not bent nor humped at the level of Th. II.
Pseudopores (Figs 2E, 2G, 3I–H, 4A–B, 5D) present as round flat disks, as large as mac sockets, present on various parts of body: antennae, head, tergites, coxae and manubrium. On antennae, psp located at the tip of Ant. II–III (two on each segment) (Figs 2E, 2G). On head, 1+1 psp located laterally, anterior to the PAO (Fig. 3I). On tergites, 1+1 psp close to the axis from Th. II to Abd. IV (Fig. 4A). On coxae, 2+2 psp on coxa I, 1+1 psp on coxa II, 2+2 psp on coxa III, close to the longitudinal rows of chaetae (Fig. 4B). On manubrium, 2+2 dorso-apical psp (Fig. 5D).
Antennae (Fig. 2). Antennae about 1.1–1.4 times longer than the cephalic diagonal, and 0.29–0.45 times the length of the body (head + trunk) (N=9). Antennal segment I subdivided, Ant. III and IV annulated, except for the proximal and distal parts of both segments (Fig 2A). If Ant. II and III fused, segment not annulated. Antennal segment ratio as I(a+b):II:III:IV = 1:1.41: 1.81: 2.66. Antennal chaetae diverse, with ordinary chaetae, S-chaetae (as described by Jantarit & Sangsiri 2020) and scales. Scales oval to rounded, of medium size (7–13 X 14–28 μm), with dense cover of short spicules arranged in more or less regular longitudinal lines; numerous scales present dorsally on Ant. Ib and Ant. II, few on Ant. Ia dorsally; absent on Ant. III–IV. Sens and sens-like chaetae present on all antennal segments, of 13 morphological types similar to the ones described by Jantarit & Sangsiri (2020) (not redescribed in detail here). Ant. I subdivided into Ia and Ib (Figs 2A–C). Ant. Ia always shorter than Ib. Ant. Ia dorsally with two basal mic (type g) and few thick ciliated chaetae (type b); ventrally with three pointed smooth mes (type e) and one hyaline smooth mic (type m) (Figs 2B–C). Ant. Ib dorsally densely covered by scales and ciliated chaetae (type a and b), with a smooth basal mic (type g); apical row with four hyaline, smooth mic (type m), one pointed smooth mes (type e) and one thin, long, hyaline S-chaetae (type l); ventrally, densely covered by ciliated chaetae (type a and b); apical row with three pointed smooth mac (type d) and five pointed smooth mes (type e or f); lateral side with three large swollen blunt S-chaetae (type h), five thin, long hyaline mes (type l) mixed with other three types of Schaetae (type e, i, k) variously interspersed (Figs 2B–C). Ant. II dorsally with scales mixed with many thick ciliated chaetae (type a and b), distally with eight pointed smooth mes (type e or f); three swollen S-chaetae (type h); three thin long hyaline mes (type l); and four thin hyaline rather short chaetae (type k), basally with three pointed smooth mic (type g); ventrally densely covered by thick ciliated mes (type b), with two pointed smooth mic (type g) basally, mixed with four pointed smooth mac (type d), two large swollen S-chaetae (type h), eight thin long hyaline S-chaetae (type l), and 16 pointed smooth mes (type e or f) (Figs 2D–E). Ant. III without scales, chaetotaxy with tendency to form whorls of chaetae; dorsally densely covered by many thick ciliated mes (type b and c) with two pointed smooth mic (type g) basally, mixed with six types of S-chaetae (type e,f, h, i, k, l) variously interspersed; ventrally densely covered by many thick ciliated mes (type b) with two pointed smooth mic (type g) basally, mixed with four types of S-chaetae (type e, f, h, l) variously interspersed (Figs 2F–G); Ant. III organ with five sens; sens one (type m) longest, hyaline and acuminate; sens four (type i) hyaline, rather long, apically blunt; sens five (type j) dark, shortest; sens two and three (type h) as swollen curving rods (Figs 2F, 2K). Antennae sometimes asymmetrical due to the fusion of Ant. III and IV, Ant. III distal chaetae strongly modified if Ant. III and IV fused as a result of accidental segment loss (Figs 2A, left antenna). Ant. IV annulated, except at the tip, without apical bulb, chaetotaxy with tendency to form whorls of chaetae; dorsally densely covered by many thick ciliated mes (type b and c) mixed with four types of S-chaetae (type e, f, k, l) variously interspersed; ventrally densely covered by many thick ciliated mes (type b and c), mixed with four types of S-chaetae (type e, f, k, l) variously interspersed. Pin projection on apex not seen (Figs 2H–I). Subapical organite not distinctly knobbed, apically not enlarged, inserted dorsally near to the tip of Ant. IV, with apical guard chaeta (Fig. 2J).
Mouthparts (Figs 3A–F). Maxillary outer lobe with one basal chaeta, simple maxillary palp, four sublobal appendages, all smooth (Fig. 3A). Mandibles asymmetrical (right with four and left with five teeth) on all examined specimens; molar plate with three to four strong pointed basal teeth (Fig. 3B). Maxilla with a strong tridentate claw, with four or five stout ciliated lamellae, with two or three well-developed sharp beaks on each side opposite to the maxilla capitulum, and a thin long rod bent inwards towards the capitulum (Fig. 3C). Labial palp with five smooth acuminate proximal chaetae in papillae, accessory appendages following the formula: A=0, B=5, C=0, D=4, E=5, like those described by Fjellberg (1999) for the Entomobryidae, hypostomal chaeta (H) with two accessory appendages (h1 and h2). Labial papilla E with lateral process subcylindrical apically, not reaching the apex of the papilla (Fig. 3D). Labrum with four conical and minute papillae (Fig. 3F); ventral complex of labrum with two slightly asymmetrical multi-toothed combs and a pair of thin, sinuous, unequal tubules below (Fig. 3E). Prelabral and labral chaetae following the formula 4/5, 5, 4, all smooth, acuminate, subequal, except for the chaetae on the proximal row slightly longer than others (Fig. 3F).
Ventral head chaetotaxy (Figs 3G, 3J). Chaetae of labial basis as M 1m 2_el1l2, chaetae M1 ciliated, m2 and l1 smooth, subequal and longest, r absent (r possibly as a scale) (Fig. 3G). Postlabial quadrangle (PLQ) with 2+2 weakly serrated chaetae (Fig. 3J); postlabial region densely covered by scales and weakly serrated chaetae illustrated in Fig. 3J. Dorsal head chaetotaxy (Figs 3H–I, 4A). Dorsal head chaetotaxy with stable chaetae arrangement as in Figs 3H and 4A. Head ‘An’ series with 7+7 chaetae (5+5 mac and 2+2 mes in the anterior region, surrounding the antennal bases), ‘A’ series with 5+5 mac (A0, A2–A5), A1 as a mic; ‘M’ series with 1+1 mac (M1), sutural mac with 7+7 mac (S0, S1, S3–6, S6i), and 3 unnamed mic between series ‘M’ and ‘S’; interocular series with 3+3 chaetae (p as mac, t as mes, r as mic); postsutural area with 3+3 mic (Ps2–3 and Ps5); postoccipital anterior area with 1+1 mac (Pa5), 1+1 short cephalic tric (Pa6) and 1+1 unnamed mic laterally; postoccipital posterior area with 3+3 mic (Pp3 and Pp5–6); head laterally with several unnamed mac. Eyes absent. PAO shape irregular (two overlapping superposed oval vesicles by a smaller roughly circular disc) located just below the antennal mac (Figs 3H–I, 4A).
Tergites and genital plate (Fig. 4A). Dorsal chaetotaxy summarized in Fig. 4A. Formulae from Th. II–Abd. V of: psp as 1,1/ 1,1,1,1,0; tric as 0,0/0,2,3,2,0; ms as 1,0/0,0,1,0,0; sens as 2,2/1,3,34,3; mac as 13,8/3,1,2,6,5. Mac arrangement stable; Th. II with 6+6 anterior central mac (a5, m1–2, m4, m4i, m4p) and 7+7 posterior mac (p1–3, p5, p1p, p3p, p2a); with 3+3 mic (m5, p1p2, p4) and four unnamed mic laterally. Th. III with 7+7 central mac (p1–3, p1a, a4–5 and an unnamed mac near p1a) and 1+1 lateral mac (a6); 8+8 mic (m1, m4–5, p4–6, p2a, m6pe) and 4+4 mes (a7, m7, m6, m6p). Abd. I with 3+3 central mac (m2–4) and 8+8 mic (a1–6, m6, p6) and a row of 3+3 unnamed mes laterally. Abd. II with 1+1 central mac (m3); 13+13 chaetae (a1–3, a6–7, m3e, m5– 6, p4, p6–7 as mic; a5 and m2 as tric) and two unnamed mic laterally. Abd. III with 1+1 central mac (m3) and 1+1 lateral mac (pm6); 14+14 chaetae (a1–3, a6–7, m4, m7, am6, p4 as mic; p6–7 as mes; a5, m2, m5 as tric), with four unnamed mic laterally. Abd. IV with 2+2 central mac (A6, B5); 4+4 lateral mac (E1, E3, Ee10, F3); with 23+23 chaetae (A2–3, A5, B2, Be2, C1, T1, T3, T5, D1, E2, Ee11, D3p as mic; C4, T6–7, D3, F1-2, F3a as mes; T2 and T4 as tric); and at least 10+10 S-like chaetae. Abd. V with 2+2 central mac (p3–4) and 3+3 lateral mac (m5, a6, ap6); with 12+12 chaetae (a1, a3, a5, m5a, p1, p1p, p3pi, p4p as mic, p5, p6ai, 3pe, m5e as mes), with several unnamed mic and mes laterally. Abd. VI dorsally with 1+1 ciliated mic and at least 13+13 ciliated mac mixed with mes. Each anal valve ventrally without smooth chaetae, with several serrated mes mixed with mac, mic not seen. Genital plate as in A. whitteni Jantarit & Sangsiri, 2020. Female with 2+2 smooth mic, one pair on anterior and posterior lobes. Male with many acuminate, smooth circumgenital mic not clearly seen, without modified chaetae. Spermathecal duct elongated, rather smooth.
Legs (Figs 4B–D) with ordinary ciliated chaetae of various lengths (mes to mac), smooth chaetae and scales; mic not seen. Scales present on coxae, trochanters and femurs. Tita III slightly longer than tita I–II. Subcoxa I with 3+3 mac, subcoxa II with 2+2 mac and 2+2 mes, subcoxa III with 3–4+3–4 mac and 5–6+5–6 mes (Fig. 4B). Coxa I with two anterior mes, two proximal psp, and three posterior mac; coxa II with one proximal psp, three mac in the anterior row, 4–5 mac in the posterior row, and at least six mes posteriorly; coxa III with nine chaetae (four mes and two mac anteriorly, two proximal psp, and three mes posteriorly). Trochanteral organ with 19–22 smooth, straight, unequal spine-like chaetae (Fig. 4C). Distal whorl of tita with 10 subequal ciliated chaetae, irregularly arranged, and a thin, acuminate, smooth tenent hair. Tita without rows of long smooth chaetae internally. Ventro-distal smooth chaeta of tita III thin, erected, pointed, longer than the tenent hair and the unguiculus. Pretarsal mic minute on anterior and posterior sides (Fig. 4D). Ungues outer teeth not seen; inner edge with paired basal teeth, unpaired teeth absent. Unguiculus about half as long as the inner edge of the unguis, slightly swollen baso-internally, pointed apically, with a large outer tooth (under light microscope), devoid of inner teeth (Fig. 4D).
Ventral tube and tenaculum (Figs 5A–C). Ventral tube about 1.5 times longer than wide; with scales on the posterior side; anteriorly with 2+2 ciliated chaetae, five weakly serrated chaeta with about the same size (Fig. 5B); posteriorly with 1+1 smooth chaetae, 4+4 ciliated chaetae mixed with 2–3 weakly serrated chaetae proximally (Fig. 5C). Lateral flaps with 7+7 smooth chaetae (Fig. 5C). Tenaculum with one smooth chaeta and four large teeth of decreasing sizes from the basis to the apex of each ramus (Fig. 5A).
Furca (5D–F). Ratio of manubrium (average): dens: mucro = 25: 38: 1. Mucrodens 1.25 times longer than manubrium (holotype). Manubrium dorsally densely covered by ciliated mes, with a row of four smooth chaetae on each side. Manubrial plate with 2+2 psp and three ciliated chaetae (Fig. 5D). Manubrium ventrally densely covered with medium size scales, chaetae not seen. Dens curved, tapering, with a rather short basal part strongly crenulated, long medial part with well-defined dorsal crenulations, and short, thinner, smooth distal part, smooth section about four times as long as the mucro. Dens basally with 1+1 row of 5–8 finely ciliated spines on the inner side, asymmetrical (Fig. 5E) and 1+1 smooth chaetae latero-externally; laterally densely covered by ciliated mes; ventrally densely covered by medium sized elongated scales, mixed with ciliated mes; scales absent on the distal uncrenulated part. Mucro bidentate, without the basal spine (Fig. 5F).
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Legends:?– no information; c–ciliated; se–serrated and s–smooth. The chaetotaxy of Th. II of A. tetracanthus follows Mari-Mutt (1977, 1982 b) and Prabhoo (1971).
Etymology. The species name is derived from the word ‘arboreal’, which means ‘living in trees’, referring to the presence of A. arborealis in forest canopies. The name also highlights the presence of springtails in the canopy forests of the Philippines.
Remarks. Alloscopus arborealis sp. nov. differs from all other blind Alloscopus species by the following combination of characters: head with 7+7 mac on ‘An’ series, and one mac in ‘M’ series (vs. three in the other species); 13+13 mac on Th. II (vs. 9–12); 7+7 inner mac on Th. III (vs. 6+6); Abd. IV with four short sens (vs. three); small number of chaetae on ventral tube posterior face (4–5 vs. 11–23) and lateral flap (7 vs. 9–16), and absence of ms on Abd. I (vs. presence). The absence of the ms on Abd. I in the new species is unexpected, as it is usually present in Alloscopus and almost all genera of Entomobryoidea (Zhang & Deharveng 2015). However, the ms is constantly absent on the Abd. I of all of our specimens (nine studied individuals). The loss of the ms on Abd. I may be considered an apomorphic character of A. arborealis sp. nov. The new species is most similar to A. deharvengi (Mari-Mutt, 1985) in Mari-Mutt (1985b) in the absence of pigments and eye patches; similar body size and PAO shape; number of mac on head ‘A’ and ‘S’ series, labial basis chaetotaxy, number of spiniform labral papillae; number and homology of anterior mac on Th. II; absence of ungual inner unpaired teeth; and number of smooth chaetae on the manubrium. However, it differs from A. deharvengi in the absence of Ant. IV apical pin chaeta, smooth chaetae on tita and on lateral anal valves (vs. presence); in having 7+7 mac on head ‘An’ series (vs. 5+5?), and one mac in series ‘M’ (vs. three); weakly serrated chaetae on PLQ (vs. smooth); number of lateral processes on labial papilla E (five vs. four); and number of mac on Th. II–III (13 and 8 vs. 12 and 6, respectively). The main diagnostic characters of the new species and all seven blind taxa of the genus are provided in Table 1.
Alviola et al. (2021) first reported this species as Alloscopus sp. It is the eighth blind species of Alloscopus described so far.
Ecology. The new species is present on both the canopy (suspended soil in tree branches) and forest floor (decaying leaves) of many vegetation types in Mt. Makiling, Philippines. They are relatively more abundant in the lowland forest (~ 270 m asl.) and mahogany plantation (~ 290 m asl.), and are observed to decrease in abundance up to the upper montane forest (~ 900 m asl.). Some of the plant species known to harbor this species are Dillenia philippinensis, Swietenia macrophylla, Arenga pinnata, Pterocarpus indicus, Dysoxylum gaudichaudianum, and Diplodiscus paniculatus. Specimens of Alloscopus arborealis sp. nov. can be seen up to 17 m in the canopy height.
description: Published as part of Alviola, Marnelli S., Lucañas, Cristian C., Lit, Ireneo L., Soto-Adames, Felipe N. & Jantarit, Sopark, 2024, A new canopy-dwelling species of the genus Alloscopus Börner (Collembola: Orchesellidae: Heteromurinae) from Mt. Makiling, Philippines, pp. 281-295 in Zootaxa 5405 (2) on pages 283-293, DOI: 10.11646/zootaxa.5405.2.8, http://zenodo.org/record/10603474