Ommatocepheus quetzalli Revelo & Martínez, 2025

Ommatocepheus quetzalli Revelo & Martínez sp. nov.

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( Figures 1–26 View FIGURES 1–3 View FIGURES 4–6 View FIGURES 7–12 View FIGURES 13–19 View FIGURES 20–26 )

Diagnosis. Body length 547–658. Notogaster and ventral plate foveolate, circumdorsal suture with foveolae surrounded by irregularly sclerotized bands; lamellae broad with long lamellar cusps terminating in long, broad protrusions; lamellar setae longer than lamellar protrusions, interlamellar setae thick, rod-shaped; bothridial seta globose, with short stalk fully immersed in bothridium small anterolateral opening. Subtriangular humeral processes present; notogastral setae covered with cerotegument, three anterior pairs of setae rod-shaped (la, lm slightly curved in some specimens), remaining setae curved, two pairs visible ventrally. Six pairs of small setiform and smooth genital setae; two pairs of anal and three adanal setae, long, wavy, covered with cerotegument.

Description of adult. Measurements. Body length: 547 (holotype, male), 647 (paratype, one male), 588–658 (paratypes, three females); notogaster width: 329 (holotype), 376 (paratype, one male), 352–400 (paratypes, three females). Thickness: 207–270. Length/width: 1.6–1.8.

Integument. When dry, body is iridescent, dorsal coloration yellowish-green, ventral turquoise-lilac (around anal plate); immersed (in alcohol or lactic acid) specimens, dark brownish-brown coloration, lamellar protrusions blackened. Irregular cerotegument layer on body may accumulate spores and detritus along the sejugal suture or between lamellae, microgranular cerotegument in lamellar projections and legs, generating a velvety appearance. Prodorsum surface smooth, central region of notogaster with rounded foveolae (7–9) surrounded by broad, sclerotized bands. Similar foveolate pattern on edge of ventral plate, inner and anal plate only foveolate.

Prodorsum ( Figures 1 View FIGURES 1–3 , 4 View FIGURES 4–6 ). Rostrum rounded (slightly distorted in some specimens). Lamella long, broad (77 × 48), lamellar cusps (38 × 31) narrower at insertion of lamellar seta, ending in elongated protrusion (42–69 × 14–16) with rounded tip; lamella and anterior section of lamellar cusps auriculiform in appearance; translamella reduced to chitinous band. Prodorsal setae (le>ro>in>ex); rostral seta (46–66) on tubercles, centrally curved, slender, flexible, slightly barbed, with a fine tip, both tips pointing to the same side (right). Lamellar setae (96–128) curved, thick at the base, rigid, smooth, with fine tip, tips facing inwards, exceeding lamellar protrusions. Interlamellar seta (36–40) small, thick, rod-shaped, smooth, slightly widened distally; a chitinous band projects anteriorly among the setae. Exobothridial seta (9) minute and smooth. Bothridial seta (24, diameter) globose, dark, short stalk (7–12), head laterally inclined. Bothridium covering completely bothridial seta ( Figure 15 View FIGURES 13–19 ), with small scalloped antero-lateral opening, anterior protrusion of bothridium meeting posterior end of lamella. Tutorium absent.

Notogaster ( Figures 1, 3 View FIGURES 1–3 , 4, 6 View FIGURES 4–6 ). Anterior margin irregular. Subtriangular humeral process present. Circumdorsal scissure complete, wavy. Nine pairs of notogastral setae (27–33), rod-shaped, dark, covered with cerotegument, setae la always straight, setae lm and lp sometimes slightly curved, h 3, h 2, h 1, p 3, p 2 and p 1 curved downward (one paratype with small seta c on right humeral projection). Opisthonotal gland opening present, anterior to lp. Lyrifissures (im and ip dorsal, ia, ih and ips lateral) ia shortly before la level, im between lm and lp before gla, ih and ips transverse, at the same level as the h 3 -h 2 and h 2 -h 1 setae respectively (in one specimen, ips dorsally located, between setae).

Gnathosoma ( Figure 13 View FIGURES 13–19 ). Subcapitulum size (133 × 94). Subcapitular setae (h>a>m) setiform, smooth, h (29–30) straight, sometimes covered with cerotegument, a (17) and m (13) small, very thin. Triangular genae, poorly developed longitudinally, so that setae a and m are aligned horizontally. Atelebasic rutella with ventral lobes overlapping in the midline. Palp size 75, palpal setal formula 0-1-1-3-9 (1) ( Figures 12 View FIGURES 7–12 , 14 View FIGURES 13–19 ); solenidion of palptarsi lateral, 1/2 length of tarsus. Chelicera (138 × 56) with two setiform and smooth setae, cha (27) longer, thick than chb (20) ( Figure 11 View FIGURES 7–12 ).

Epimeral and lateral podosomal region ( Figures 2, 3 View FIGURES 1–3 , 5, 6 View FIGURES 4–6 ). Epimeral formula 3-1-3-2; setae setiform and slightly barbed; 1b, 3b, 4a, 4b (25–37) longer than 1c, 2a, 3a (11–13), 1a (7–9) smallest. Discidium triangular with rounded apex. Pedotecta I and II well developed.

Anogenital region ( Figures 2 View FIGURES 1–3 , 5 View FIGURES 4–6 ). Genital opening size (104–121 × 97–117); six pairs of genital setae (21–30), setiform, smooth. Aggenital setae (22–24) shorter than genital setae. Anal opening (105–149 × 109–124) with triangular sclerite on anterior edge of anal plates, pre-anal organ under it; two pairs of anal setae (47–66), three pairs of long thick adanal setae (65–87), setiform, slightly curved, cerotegument cover flat and broad, extending beyond the setae tip. Lyrifissure iad parallel to anal plate.

Legs ( Figures 7–10 View FIGURES 7–12 , 16–19 View FIGURES 13–19 ). Legs homotridactylous, with strong claws. Tarsus I–IV with dorsal posterior lyrifissure. Trochanter III–IV with an anterior dorsal tooth. Porous areas on postero-dorsal section of femur III–IV. Formula of setae and solenidia of legs: I (1-4-2-5-16) [1-2-2], II (1-4-2-4-15) [1-1-2], III (2-3-1-3-15) [1-1-0], IV (1- 2-1-3-13) [0-1-0] (table 1). Solenidia ω 1 slightly longer than ω 2, famulus 1/3 the size of solenidium ω 1; solenidium φ 1 long, remaining solenidia small (tibia I–IV, genu I–III). Setae p and s on leg I smooth (eupatidial aspect), remaining tarsal setae flattened, broadened at base, marginally bearded and ending in tip, setae ft less flattened; tarsal setae it, tc and ft of legs II–IV ribbon-shaped, marginally bearded, remaining setae flattened, broadened at base, marginally bearded and ending in tip.

Type deposition. The holotype and four paratypes preserved in 70% alcohol and glycerin, was deposited in the collection of Colección Nacional de Ácaros ( CNAC), Universidad Nacional Autónoma de México ( UNAM) and a paratype preserved in 70% alcohol and glycerin, was deposited in the mite collection of the Colegio de Postgraduados, México .

Etymology. The name quetzalli is translated from Nahuatl as ‘precious’ or ‘beautiful’, and in turn gives its name to the astonishing quetzal ( Pharomachrus mocinno ), whose metallic green color and long tail feathers create an exceptional resemblance to the coloration and long adanal setae of this species of Ommatocepheus .

Remarks: The new species resembles O. clavatus japonicus Aoki, 1974 by the shape of the notogastral setae and the size of the ad 1–2 setae; however, it differs in the shape of the interlamellar seta (claviform vs. rod-shaped) and in the size of the ad 3 seta (short vs. long). Also, it shows similarities with O. ocellatus ( Michael, 1882) by the ornamentation of the notogaster and shape of notogastral setae, but differs in the size of the adanal setae (short vs long), shape of the interlamellar seta (lanceolate vs rod-shaped) and thickness of the lamellar protrusions (similar thickness to lamellar setae vs thicker than lamellar setae). Ommatocepheus quetzalli is, along with O. reticulatus , the largest known species, exceeding the others in length by 7 to 20%.

Description of tritonymph. ( Figures 20–26 View FIGURES 20–26 )

Measurements. Length: 543; width: 329.

Integument. Smooth, microgranules of cerotegument arranged on body; ventral plate strongly striated. Dense accumulation of cerotegument and detritus on scalps, making difficult to observe setae from earlier stages of development.

Prodorsum ( Figure 21 View FIGURES 20–26 ). Rostrum with slight rounded projection; rostral setae (27) ( Figure 23 View FIGURES 20–26 ) setiform, arising in apophyses; lamellar setae (118 × 100) ( Figure 25 View FIGURES 20–26 ) lamellate, leaf-shaped with slightly wavy margins, six or seven veins arising near seta insertion and divided distally; interlamellar seta (65) filiform, with lateral barbulations and arranged on small apophyses; bothridial seta (14) ( Figure 22 View FIGURES 20–26 ) small, setiform, with scattered spines and curved at the base; bothridium reduced to a bothridial scale, arranged inferior to bothridial seta; exobothridial seta (11) setiform, straight, smooth. A transverse costula arises from the bothridia and passes through the interlamellar setae, mediumdeep longitudinal depression is formed posterior to this and rises anteriorly, showing a short canal.

Gastronotic region. Typically eupheredermous ( Grandjean 1954; Woas 1990). Median region of the sejugal border with an apophysis (14 length, 13 diameter) ( Figures 21, 24 View FIGURES 20–26 ) projecting upward, covered with cerotegument granules (in dorsal view it has the appearance of a pollen granule). Nine pairs of notogastral setae, c 1 (102 × 45) ( Figure 26 View FIGURES 20–26 ) flabellate, with broad, rounded projection on anterior edge and two lateral pointed tips, seta c 2 similar to lamellar seta and other notogastral setae la, lm, lp, h 3, h 2, h 1, p 1 (111 × 82), but considerably larger (181 × 130).

Gnathosoma . Subcapitulum size (114 × 76). Subcapitular setae: h 19, a 11, m 10, smooth, with very fine tip; rutellum atelebasic, edge plane with a prominent lateral tooth. Palp size 51, palpal setal formula 0-1-1-3-9 (1); solenidium (3) independent of eupathidium acm (3) slightly broader.

Anogenital region. Five pairs of genital setae (19) setiform, smooth, acuminated; aggenital seta small (7). Anal (19) and adanal (29) setae similar in shape to genital setae, adanal setae appear soladiate to small apophyses.

Legs. Tarsi monodactylous.

Remarks: The immatures of Ommatocepheus along with those of Conoppia palmicinctum ( Michael, 1880) are distinguished from other species of the family by the widened shape of the notogastral setae of the nymphs ( Colloff 2023; Michael 1880, 1882). Although with the caution of having studied only one tritonymph of O. quetzalli , it is important to compare it with the tritonymph of O. ocellatus : the immatures of the two species resemble each other in the shape of the bothridial and exobothridial setae, the size difference of the c2 seta compared to the remaining notogastral setae, and the presence of a depression posterior to the interlamellar setae (see Travé 1963: Figure 24 View FIGURES 20–26 , 50). However, the tritonymph of O. quetzalli differs in the shape of the interlamellar setae (filiform vs claviform), c1 setae (flabellate vs bacilliform), venation of the notogastral and lamellar setae (six or seven longitudinal veins vs multiple longitudinal veins interconnected like a spider web), presence of an apophysis in the sejugal region vs absence, and the shape of the rostral setae (setiform vs filiform). In figure 7 of Michael (1880) and figure 3 of Ritchers (1900) of O. ocellatus , a lamellate seta is shown inserted laterally on the prodorsum, almost at the level of the interlamellar setae, we assume this is an incorrect placement of the c2 seta.