Scapheremaeus subiasi, Palacios-Vargas & Jaimes Murillo & Ojeda, 2024

Palacios-Vargas, José G., Jaimes Murillo, Kevin A. & Ojeda, Margarita, 2024, New species of Scapheremaeus (Acari: Oribatida: Cymbaeremaeidae) from an epiphytic environment in Morelos, Mexico, Zootaxa 5556 (1), pp. 97-105 : 98-99

Scapheremaeus subiasi sp. nov.

( Figs. 1–12 )

Diagnosis. Body size: 434 × 217. Body surface foveolate-reticulate. Costulae well developed and lamellar setae associated with a tubercle. Costulae ridge-like, fully developed, interrupted medially in some of the specimens. Sensillum clavate, with a pigmented capitulum, sometimes very dark. Humeral process present. Ten pairs of notogastral setae of two different types. Six pairs of genital setae. Semi-round lenticule (33 × 36). Monodactylous.

Description. Measurements. Body length: 434, width 217 (holotype, female), paratypes (five); length 433–305 (394) and width 236–207 (221).

Integument. Body color light to dark brown. Body surface densely foveolate ( Figs. 1 and 2 ), lateral sides with parallel ridges and troughs which are also shown in the femora of all legs.

Prodorsum ( Figs. 1 , 3 ). Rostrum rounded. Costulae well developed, terminated by tubercles bearing lamellar setae. Costular ridge sometimes incomplete. Rostral setae (ro, 20) setiform, smooth, directed medially. Lamellar setae minute (le, 10) setiform, straight ( Fig. 4 ). Interlamellar and exobothridial setae and alveoli absent. Bothridium (bo) irregular shape. Sensillum (ss, 53) club-shape, with dark pigmentation, and a short stalk ( Fig. 4 ).

Gnatosoma ( Figs. 5–6 ). Subcapitulum longer than wide. Subcapitular setae thin, smooth; m shorter than a and h ( Fig. 5 ). Palps with setation 2-1-3-7 (+ w). Chelicerae with two pectinate setae; cha slightly shorter than chb. Trägårdh´s organ long, tapered ( Fig. 6 ).

Notogaster ( Figs. 1 , 3 and 8 ). Length (n= 6): 364–315 (333); width: 256–216 (232). General shape irregularly elliptical, almost square in the most anterior region. Lenticulus (len; 36 x 30) distinctly round. Humeral region with a well–developed process. Centrodorsal region (247 x 153) with foveolate microsculpture, and well-developed diagonal extensions towards the humeral region close to setae c2. Circumdorsal scissure complete. Ten pairs of notogastral setae, c2, la, h1, h2, h3, p1, p2 and p3 rod-shaped ( Fig. 3 ). Setae lm and lp are small, spiniform and located in the centrodorsal region. Lyrifissures im, ip, ih visible, located in the circumdorsal border and lyrifissure ips and opisthonotal gland opening gla are not visible (Figs. 3,8).

Epimeral region ( Fig. 7 ). Microsculpture predominantly foveolate, including the epimeral region and the genital and anal plates, and parallel ridges on the sides from the epimeral region onwards ( Fig. 2 ). Epimeral chaetotaxy: 3-1-2-2, setae setiform and minute.

Anogenital region ( Figs. 2 , 7–8 ). Five pairs of genital setae (g1-g6), g1, g2 and g3 located adjacently on the anterior margin, followed by a pair of aggenital setae. Anal plate is longer than wider, with two pairs of setae, three pairs of adanal setae and lyrifissure iad in paranal position. Genitoanal chaetotaxy: 6-1-2-3 ( Fig. 7 ). Microsculpture in the region foveolate in the center, to the sides consisting of parallel ridges and troughs ( Fig. 2 ).

Legs ( Figs. 9–12 ). All legs with tuberculate microsculpture and a series of parallel ridges on anti-axial surface. Porose areas (p.a.) clearly visible and oval shape in femur of all legs. Formula of leg setation and solenidia: femur-genua-tibia-tarsus (solenidia): leg I: 4-2(1)-4(2)-16(2); leg II: 4-2(1)-3(1)-14(1); leg III: 2-1(1)-3(1)-14; leg IV: 2-1(1)-3(1)-12. Length of leg segments I and II (femur-genua-tibia-tarsus): leg I: 85-24-58-23, leg II: 79-22-43-87; legs III and IV (trochanter-femur-genua-tibia-tarsus): III: 39-69-22-43-87, IV: 41-65-23-52-28. Total length of legs (from femur to tarsus): 190, 231, 221, 168. Monodactylous.

Type locality. MEXICO: Morelos: Sierra de Huautla , El Zapote, ex. Epiphytic moss and lichens. 1-X-2021. V. Granados, coll.

Type material. Female holotype and 7 paratypes in semipermanent slides (one stored in alcohol). All deposited in the collection of Laboratorio de Ecología y Sistemática de Microartrópodos, UNAM .

Etymology. The species name subiasi is dedicated to Dr. Luis Subías, in homage to the tireless oribatologist who left us an important legacy with his Catalogue of Oribatid Species.

Remarks. Scapheremaeus subiasi sp. nov. is morphologically most similar to S. magdalenae Palacios-Vargas & Ríos, 1998 and S. hectorperezius Palacios-Vargas & Ríos, 1998 from Cedros Island, Baja California and Los Tuxtlas, Veracruz respectively. They share the presence of a humeral process, ten notogastral setae, monodactylus legs and microsculpture of the body represented by a foveolar pattern, as well as an anal plate that is longer than wider. However, the new species differs from the two mentioned species by the larger body size 439 x 222 and 365 × 180, respectively. The localization of lamellar setae on well-developed lamellar tubercules (vs. absent or inconspicuous), and type and size of setae ro and le (smooth vs basiliform, barbulate; le smaller than ro, vs same size). The most evident difference between these species in the general appearance is the posterior end of notogaster, Scapheremaeus subiasi sp. nov. has a smooth contour vs. a constriction and crest on the border shown in the other species.

Figures

FIGURES 1–2. Scapheremaeus subiasi sp. nov. microphotographs. 1, microsculpture pattern, dorsal view of the body; 2, microsculpture of genito-anal region.

FIGURES 3–4. Scapheremaeus subiasi sp. nov. 3, dorsal aspect (legs removed), scale bar = 50 μm,; 4, sensillum (ss), rostral (ro) and lamellar (le) setae, scale bar = 20 μm.

FIGURES 5–8. Scapheremaeus subiasi sp. nov. 5, subcapitulum showing setae m, h and a, scale bar = 20 μm; 6, right chelicerae, cha, chb, cheliceral setae; scale bar = 20 μm; 7, ventral aspect (legs removed), scale bar = 50 μm; 8, lateral aspect (legs removed), scale bar = 50 μm,

FIGURES 9–12. Scapheremaeus subiasi sp. nov. 9, chaetotaxy of leg I; 10, chaetotaxy of leg II; 11, chaetotaxy of leg III; 12, chaetotaxy of leg IV. Porose area (p.a.) Scale bar = 20 μm.