Megalothorax nigropunctatus , Schneider & D'Haese 2013
Creators: name: Schneider, Clément
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Entognatha
Collembola
Neelidae
Megalothorax
Megalothorax nigropunctatus

description: Megalothorax nigropunctatus Schneider & D’Haese, 2013
Figs 3 D, 4D, 6, 15A, B, 20, 21.
Material examined. Holotype. ♂ on slide (MNHN-EA 040153), Chile, Puerto Montt, Parque Nacional Alerce Andino, 41°34'58"S 72°34'1"W, 25.xi.2011, captured with aspirator under the bark of a dead tree, C. Schneider leg., [MNHNCH]. Paratypes. 10 ♀, 5 ♂ on slides (MNHN-EA 040154 –161) same data as the holotype, [MNHNCH]; 12 ♀, 4 ♂ and 4 juveniles on slides (MNHN-EA 040162 –169), same data as the holotype, [MNHN]; 8 spm on mount for SEM (MNHN-EA 041007), same data as the holotype, [MNHN].
Description. Addendum to Schneider & D’Haese (2013).
Adult. Total length of antenna ~ 100 µm; max width (Ant. III) ~ 22.5 µm; ratio width: length = 0.225; ratio length of Ant. I: Ant. II: Ant. III: Ant. IV ~ 0.36: 0.53: 1: 1. Correction from Schneider & D’Haese (2013): with six ordinary chaetae on Ant. IV (Fig. 14 A, B). Testis as in Fig. 20 A.
Juvenile. The difference of chaetae between juvenile and adult chaetotaxy is similar to what have been described for M. minimus with one exception: the chaetae β3 are specific to the adult of M. minimus and appear during the post-embryonic development. The supplementary chaetae on M. nigropunctatus in regard to M. minimus (on fields of labium and Abd. IV sternum) are present in the juvenile.
Size. Length from labrum to anus: ~300 µm.
Pigmentation. White (in ethanol).
Body shape and segmentation. Orthognathous. Ratio height: length of head ~ 0.75. Total length of antenna ~ 50 µm; max width (Ant. III) ~ 8 µm; ratio width: length ~ 0.16; ratio length of Ant. I: Ant. II: Ant. III: Ant. IV ~ 0.4: 0.6: 1: 0.88. On each leg, length of coxa> tibiotarsus ~ femur ~ trochanter. Length of manubrium: dp: dd: mucro ~ 0.81: 0.68: 1: 1.
Granulation. Secondary granulation present. Dorsal protuberance T present at the posterior extremity of the dorso-median line (Fig. 20 B).
Integumentary channels. Not precisely observed, present dorsally on head, and ventrally on Th. II–Th. III but apparently less developed than in the adult (Fig. 20 B).
Chaetae. The chaetotaxic pattern and morphology are very similar to the adult though the absence of some specific chaetae and wrc (Fig. 20 B).
Wax secretory rods and sensory fields. With 6 + 6 sensory fields like the adult. Smaller inner chaeta of sf5 absent (the bigger present), inner chaetotaxy of the other sensory fields as in the adult (Fig. 20 B).
Labium, maxilla outer lobe, oral fold, labrum. All chaetae observed on the adult present.
Head chaetotaxy. Postero-dorsal area with 9 + 9 chaetae (the 2 + 2 most anterior chaetae missing); anterodorsal area with nine pairs of chaetae and two unpaired chaetae (2 + 2 chaetae missing in regard to adult near the dorsal edge of sf1, a0 present); antero-lateral areas with 1 + 1 chaetae (L; Figs 3 D, 20B). Ventral area with 3 + 3 post-labial mesochaetae (Fig. 4 D).
Antenna chaetotaxy. Ant. I with a chaeta, Ant II with four chaetae, Ant III with 10 ordinary chaetae, two long S-chaetae and two short, swollen S-chaetae (S1–S4, Ant. III sensory organ) and a long S-chaeta S (one missing in regard to adult; Figs 6, 20C). Ant. IV with six ordinary chaetae as the adult; seven S-chaetae including five thin and long (S, three missing in regard to adult), a short and thin (Sx) and a long and thick (Sy); two apical and sub-apical sensory rods (a, sa) and a short organite Or (Fig. 20 C, 6).
Th. II–Abd. V terga chaetotaxy. A total of 26 + 26 ordinary chaetae (15 + 15 missing in regard to adult), τchaetae not observed but probably present, 3 + 3 s-chaetae (s1, s2, s3), 4 + 4 sensory fields and 5 + 5 wrc (3 + 3 missing in regard to adult; Fig. 20 B). Dorso-lateral area of Th. II with 5 + 5 chaetae (a3, p2, p3 missing in regard to adult). Precoxal areas of Th. II with 1 + 1 s-chaetae (s1) and 2 + 2 chaetae (a7, a8 missing in regard to adult; Fig. 20 B). Dorso-lateral area of Th. III–anterior abdomen with 7 + 7 chaetae (a5, p2, p3, p4, α1, α2, β1, β2 missing in regard to adult) and 3 + 3 wrc (wrc2, wrc7 missing in regard to adult; Fig. 20 B). Precoxal areas of Th. III with 2 + 2 chaetae (a8 missing in regard to adult) and 1 + 1 wrc (wrc5 missing; Fig. 20 B). Posterior area of the abdomen (until Abd. V included) with 10 + 10 chaetae (η2 missing in regard to adult), 1 + 1 wrc and 1 + 1 s-chaetae (s2; Fig. 20 B). s1 short, tubular with rounded apex, s2 and s3 spherical (Fig. 20 B).
Legs chaetotaxy. With two chaetae on trochanter I (one missing in regard to adult), no chaeta on coxa II and III (one missing on each in regard to adult) and seven chaetae on femur III (one missing in regard to adult; Figs 21 A–C, Tables 9, 10, 11).
Claws morphology. Similar to the adult (Fig. 21 A–C).
Abd. VI. Tergum anterior row with 2 + 2 chaetae and an unpaired chaeta, posterior row with 2 + 2 chaetae, anal valve with one chaeta, as the adult (Fig. 20 B). Sternum with 5 + 5 chaetae including one on each anal valve.
Abd. IV sternum. With 3 + 3 chaetae and 2 + 2 neosminthuroid chaetae (as the adult).
Abdominal appendages. As the adult: manubrium with 2 + 2 posterior chaetae; dens proximal part with a posterior chaeta, distal part with a posterior chaeta, four posterior spines and three anterior spines; tenaculum with 4 + 4 apical teeth, ventral tube with 2 + 2 apical mesochaetae.
description: Published as part of Schneider, Clément, 2017, Morphological review of the order Neelipleona (Collembola) through the redescription of the type species of Acanthoneelidus, Neelides and Neelus, pp. 1-94 in Zootaxa 4308 (1) on pages 53-55, DOI: 10.11646/zootaxa.4308.1.1, http://zenodo.org/record/846086