Archisotoma jariani, Araujo De Lima & Zeppelini & Mendonça, 2019

Araujo De Lima, Estevam C., Zeppelini, Douglas & Mendonça, Maria Cleide De, 2019, Brazilian Archisotoma Linnaniemi (Collembola, Isotomidae), with description of a new species from an oceanic atoll, Zootaxa 4543 (1) : -

Archisotoma jariani sp. nov. Lima, Zeppelini & Mendonça

( Figs 1–8 , Tab 1–2)

Type material. Holotype female on slide, Brazil, Rio Grande do Norte, Atol das Rocas, (03°51'50'' S, 33°48'48'' W), intertidal sands, 08–18 Sep 2015, E.C.A. Lima leg., deposited at the CRFS-UEPB # 12261 . Paratypes: 2 males and 3 females on slides, same data as holotype, deposited at the CRFS-UEPB # 12262, 12263, 12264, 12265, 12266

Diagnosis. The new species has pigmented body, 8+8 eyes, PAO. normal, about three times longer than the closest eye. Ant. IV with 16 sensilla, manubrium with with 9-14 chaetae on posterior surface, Abd. V–VI with 2 pairs of trichobothria. Archisotoma jariani sp. nov. differs from the other Brazilian species by the number of eyes, number of chaetae on subcoxa furcalis and manubrium.

Description. Habitus typical to the genus. Color grayish. Body length 0.4–0.6 mm. Integument smooth. Holotype measurements as in Table 1.

Head and body chaetotaxy with short and smooth ordinary chaetae, some a little longer on Abd. V and VI ( Figs. 1–2 ). Axial chaetae pattern from Th. II to Abd. III as 8,5/3,3,3, axial chaetae of Abd. IV with 2 unpaired mediam chaetae between 5+5 axial chaetae, and Abd. V without a clear pattern. Abd. V–VI with 2+2 dorsal thin and smooth trichobothria, anterior pair transversally separated by 4–5 chaetae, almost twice as long as the posterior pair. Anterior and posterior pair of trichobothria separated by 3 chaetae ( Fig. 2 ).

Ant. IV with 16 sensilla poorly differentiated from surrounding ordinary chaetae; subapical organ present. Ant. III with about 32 chaetae, antennal organ with 2 small sensory rods, 2 guard sensilla and a minute lateral sensillum. Ant. II with 20 chaetae, Ant. I with 14 chaetae and a dorsal microchaeta ( Fig. 3 ). Antennae subequal in length to cephalic diagonal. Eyes 8+8, disposed in strongly pigmented eyepatch ( Fig. 4 ). PAO oval, about 3 times as long as eye diameter, with 3 surrounding chaetae. Labrum with 2 prelabral and 5,5,4 equal labral chaetae; 2 anterior rows inserted in papillae. Maxillary capitulum complex, long and slender, equal size of the lamellae; three maxillary lamellae with fringes. Labial chaeta H long and curved; 4+4 chaetae along linea ventralis.

Tita I, II and III with 20, 23, 24 chaetae, respectively; 1 thick subapical spine on Tita. III. Leg I with 1–2 curved and thick chaetae on femur and 1–2 on Tita.; leg II without differentiated chaetae; leg III with 1 curved and thick chaeta on trochanter and femur ( Fig. 5 ). Unguis without inner tooth and short, unguiculus lanceolate, about half the unguis length. Ventral tube with 4+4 laterodistal chaetae ( Fig. 6 ). Tenaculum with 4+4 teeth and without chaetae on corpus. Anterior subcoxa furcalis with 9–14 and posterior subcoxa furcalis with 9–11 chaetae ( Fig. 7 ). Manubrium with 9–14 chaetae on posterior side; and anterior side without chaetae. Dens with 7 chaetae on anterior side and 7 chaetae on posterior side ( Fig. 8 ). Mucro with 3 asymmetrical teeth, apical tooth bigger than others; mucronal seta present.

Etymology. The species is named after Mr Jarian Dantas, in honor for a life time dedication to assist scientific research and conservation on the Biological Reserve Atol das Rocas.

Discussion. Archisotoma jariani sp. nov. belongs to the besselsi group sensu ( Potapov 2001) based on its small size, Tita. III with stiff outer spur, maxillary head with thin, simple capitulum, and 3–2 pairs of trichobothria on Abd. VI. Among the species of this group, the new species resembles A. arariboia Neves & Mendonça, 2014 by presenting 1 thick and curved chaeta on trochanter and femur of leg III and 1–2 on femur and 1–2 on Tita. of leg I. The new species differs from A. arariboia by the number of eyes (8+8 vs 6+6), number of chaetae on subcoxa furcalis posterior 9–11 vs 15 and axial chaetae from Th. II to Abd. III as 8,5/4,4,4 vs 8,5/3,3,3. The new species is also similar to A. catiae differing from it in number of eyes (8+8 vs 6+6), corpus tenaculum chaeta 0 vs 1, axial chaetae from Th. II to Abd. III as 7,5/3,3,3 vs 8,5/3,3,3 and chaetae on subcoxa furcalis anterior 9–14 vs 16. A. jariani sp. nov. and A. vaoensis have the same number of eyes, but they differ in the number of posterior chaetae on manubrium (9–14 vs 23). A. jariani sp. nov. differs from A. besselsi by body length 0.4–0. 6 mm vs 1–1.5 mm, size of 8+8 eyes (8+8 ordinary vs 6+6 ordinary and 2+2 reduced in size), manubrium posterior chaetae 9–14 vs about 32. A. jariani sp. nov. and A. gourbaultae similarly differ by number of manubrial chaetae 9–14 vs 20–24, chaetae between ta. 4–5 vs 6, and chaetae on dens 14 vs 20–24. For comparison of morphological characters among the Brazilian Archisotoma species see Table 2.

Figures

FIGURES 1–2. Archisotoma jariani sp. nov. 1, head chaetotaxy; 2, chaetotaxy of thorax and abdomen, enlarged area: anterior and posterior trichobothria with 3 intermediate chaetae. Scale bars: 20 µm.

FIGURES 3–4. Archisotoma jariani sp. nov. 3, Dorsal chaetotaxy of left antenna; 4, PAO and eyes of left side. Scale bars: 20 µm.

FIGURES 5–6. Archisotoma jariani sp. nov. 5, Leg III with thick and curved chaetae on trochanter and femur enlarged; 6, Ventral tube, apical part. Scale bars: 20 µm.

FIGURES 7–8. Archisotoma jariani sp. nov. 7, Subcoxa furcalis anterior and posterior; 8, Dens and mucro. Scale bars: 20 µm.