Gustavia mexicana Revelo-Tobar & Estrada-Venegas & Martinez 2022, sp. nov.
Creators: name: Revelo-Tobar, Harol
name: Estrada-Venegas, Edith G.
name: Martinez, Armando Equihua
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Sarcoptiformes
Gustaviidae
Gustavia
Gustavia mexicana

description: Gustavia mexicana sp. nov.
(Figs 1–18)
Diagnosis. Tegument smooth, covered by a thin layer of cerotegument with many minute granules, more evident on subcapitulum; sejugal suture present; translamella absent; rostrum elongate, with rounded tip and very evident dorsally; prodorsal setae (in>le>ro) setiform and covered with small spines; sensillum with fusiform head, covered with small spines at tip; notogaster with six pairs of alveoli and three pairs of posteromarginal setae (alveolus c absent). Ventral plate typical of the family. Legs heterotridactylous.
Description of the adult. Measurements. Body length: 575 (holotype ♂), 562 (allotype: ♀), 560 (526–603) 18 paratypes; width: 424 (holotype ♂), 420 (allotype: ♀), 498 (437–531) 18 paratypes.
Integument (Figs 1–5, 15–18). Body color yellowish brown to dark brown, body surface smooth. Thin layer of densely micro granulated cerotegument covering body (ctg) (Fig 4), more evident on subcapitulum, granules slightly uniform (0.8–1.3). Lamellae slightly striate, lamellar cusps smooth. Legs I–IV without cerotegument or tubercles.
Prodorsum (Figs 1, 4, 7). Rostrum with rounded, elongated tip, completely visible in dorsal position. Prolamellae (plam) with minute plate circumscribing alveolus of rostral seta, originating from base of lamellar cusps; rostral setae (ro: 68–84) setiform, densely covered with small spines, which are only visible under a 100x objective. Lamellae (lam) slightly convergent, slightly larger than half the length of prodorsum. Lamellar cusps triangular, divergent, with distinguishable elongation extending below lamellar seta; lamellar seta (le: 70–100) setiform, proximal quarters mooth, remaining parts with small spines and less abundant than on seta ro. Translamella absent. Interlamellar seta (in: 125–136) setiform, longer than other prodorsal setae; completely covered with spines. These pines, which are near the tip are much larger and distinguishable than those near base. Sensillum (ss: length: 113–136, head width: 7–10) elongate, fusiform, generally smaller than seta in, head distinguishable, ending in short tip, stalk and head covered with spines, larger and sparser on head. Exobotridial seta (ex: 2) small, smooth, inconspicuous. Tutorium (tu) knife-shaped, a quarter longer than lamellae.
Notogaster (Figs 1, 34, 6). Dorsosejugal suture present. Nine pairs of notogastral setae present, six dorsal pairs represented only by alveoli (la, lm, lp, h 3, h 2, h 1), alveolus c absent. Three pairs of posteromarginal setae, setae (p 1: 33.6–34.8) larger than p2 and p3, the latter of equal size (20.7–22) (Table 1). The lyrifissure ia was not observed, im arranged laterally on dorsum and ip longitudinally; ih and ips only visible ventrally. Opisthonotal gland (gla) lateromarginal near lp. Muscular insertions in mid-dorsal position, between alveoli la and lm. Internal structure similar to a sigilla divided into 4–6 parts, centered anteriorly, just anterior to dorsosejugal suture.
Gnathosoma (Figs 5, 8–9, 14). Morphology typical of Gustaviidae (Ermilov et al. 2013; Norton & Behan-Pelletier 2009; Woolley 1979). Subcapitulum longer than wide (146–151.3 x 78–78.6). Subcapitular setae a (47.4–52.6), h (62.7–64.5) and m (30.2–32) setiforme, with spines. Palps (length 110–131) with setae, from coxa to tarsus: 0-2-1- 3-8 (+ ω). Eupathidium acm palpal and solenidium start from the same base. Chelicera very long (208–241 x 4.8–5) fixed digit absent, movable digit styliform, distal part with four very evident large teeth, occasionally the first tooth becomes broken, posterior portion of chelicera (1/3 of total length) with a row of teeth considerably smaller than the first and another parallel row of very fine and evident cilia, on the remaining proximal 2/3 smooth.
Epimeral and lateral podosomal region (Figs 1–3, 5, 7). Pedotectum I straight, long, almost the same length as tutorium, pedotectum II crescent-shaped. Discidium (dis) triangular, well developed. Carina circumpedal (cp) complete, not touching margin of ventral plate. Epimeric borders (bordures epimeriques sensu Grandjean) well developed and evident, posterior median edge of epimere IV with elongate chitinous structure projecting posteriorly; epimere I–III not connected, IV ends near the genital opening. Epimeral setae long, setiform, densely covered with spines, length variable: 1a, 2a, 3a (30.2–32.6), 1b (49–51.3), 1c, 3c, 4a, 4b, 4c (36–43.8), 3b (60–60.7).
Anogenital region (Figs. 2, 5–7). Six pairs of genital setae (g1–g6: 24.8–29), one pair of aggenital setae (ag: 23–27.3), two pairs of anal setae (an: 1–3: 22.8–24.6), three pairs of adanal setae: ad3 (21.9–23) in preanal position, ad2 (24.2–25.3) paraanal and ad1 (22.2–25.2) postanal; all setae setiform and smooth. Lyrifissure iad (8.7–9) in preanal position, transverse and very conspicuous.
Legs (Figs 1–3, 15–18). All legs heterotridactylous, median claw slightly larger than lateral ones, more evident on legs I–II. Trochanters III–IV considerably large. Femurs I–II longer than III and IV (Table 2). Trochanters and femora with ventral ridges, ends of ridges rounded on leg IV and ending in point on leg III; porose areas in anterodorsal position on femurs and trochanters III–IV. Setal and solenidia formulae: I: 1-5-3(1)-4(2)-20(2), II: 1- 4-3(1)-4(1)-16(2); III: 2-3-2(1)-3(1)-15; IV: 1-2-3-3(1)-12. Setae mostly setiform, with small spines, on legs I–II evident only under 100 x objective, on hind legs spines are larger and more evident. Famulus (e) setiform, straight and with rounded tip. Solenidia setiform, with rounded tip; solenidium ω1 larger than ω2 on tarsus I, similar size on tarsus II (Table 3).
Greek letters refer to solenidia (except e = famulus), Roman letters to normal setae. Single prime (’) marks setae on the anterior and double prime (”) setae on the posterior side of a given leg segment.
Material studied. Holotype, allotype and 18 paratypes: Mexico, State of Michoacán, Municipality of Nuevo San Juan Parangaricutiro, (19°23’27.8 “N 102°10’30.8 “W), 2160 m.a.s.l. and La Joya, Veracruz State (19°36’49.3”N 97°01’59.2”W) at 2210 m.a.s.l. Leaf litter and intervened primary forest floor, consisting of Pinus michoacana Martinez, Quercus rugosa Nee (1801), scattered undergrowth and leaf litter and soil of Pinus patula Schiede ex Schltdl. & Cham. forest. 1 female (17.01.2020), 1 male (15.02.2020), 1 male (13.03.2020), 1 female (10.04.2020), 1 male (15.05.2020), 1 male (13.07.2020), 2 males, 1 female (11.09.2020), 3 males, 2 females (8.10.2020), 2 males (10.01.2021), 2 males and 2 females (16.01.2022). Collected by: Edith Estrada, Armando Equihua and Harol Revelo.
Type deposition. The holotype (EGEV C-0001), allotype (EGEV C-0002) (preserved in 70% alcohol and glycerin), and 12 paratypes (EGEV C-0003-0014), in permanent preparations of hoyer liquid, were deposited in the collection of Dr. Edith Guadalupe Estrada Venegas, Texcoco, State of Mexico, Mexico. Six paratypes (three preserved in 70% alcohol and glycerin and three in permanent preparations of hoyer liquid) were deposited in the collection of CNAC-Mexico.
Etymology. The name “ mexicana ” is given because it is the first species of the genus Gustavia, described with specimens collected in Mexico.
Remarks. The species is similar to Gustavia fusifer (Koch, 1841) (= Neozetes bicornis Berlese, 1885), based the absence of the setal alveolus c and shape of the sensillum. With G. transylvanica Mahunka, 2006, it shares the rounded and elongated shape of the rostrum, shape of the lamellae and sensillum. With G. latolamellata Hammer, 1977 and G. magnifica Golosova & Karppinen, 1984, presence of sejugal suture. However, it differs from G. fusifer and G. transylvanica by the absence of translamella and presence of sejugal suture (versus presence of translamella and absence of sejugal suture). From G. latolamellata it differs by the absence of translamella, elongated and rounded shape of the rostrum (versus broad translamella present and rostrum ending in a point, slightly protruding in front of the translamella).
Gustavia mexicana shows a pattern in its habitat preferences and distribution, it has been collected in pine forest litter, moist soils, between 2160 and 2210 meters above sea level. The two sites where samples were collected are adjacent to Trans-Mexican Volcanic Belt.
description: Published as part of Revelo-Tobar, Harol, Estrada-Venegas, Edith G. & Martinez, Armando Equihua, 2022, New records of oribatid mites from Mexico with description of a new species, pp. 24-38 in Zootaxa 5168 (1) on pages 28-35, DOI: 10.11646/zootaxa.5168.1.2, http://zenodo.org/record/6885643