Tegoribates americanus Hammer, 1958

Behan-Pelletier, Valerie M., 2017, Tegoribatidae of North America, with proposal of Protectoribates gen. nov., and new species (Acari, Oribatida, Tegoribatidae), Zootaxa 4337 (2) : 169-179

Tegoribates americanus Hammer, 1958

( Figs. 9–16 )

Material examined: USA: Alaska, Fairbanks, 28.v.1948, (Lienk) 1 from sample 5 of Hammer (1955) (RNC); Denali N.P., Tolklat Ridge N.E., 29.viii.1976 (R. Greenberg) 4 from Carex and Allocomnium in willow area; Fort Yukon, 29.viii.1976 (S. Campbell) 12 from moss and alder litter; Atqasuk, Meade River IBP site, ‘Butterfly Creek’, 25.viii.1976 (A. Fjellberg) 8 from rich meadow high up on river bluff with Boykinia and Saxifraga ; same location, 28.viii.1976 (A. Fjellberg) 5 from soil of S-facing slope with sandy rich dry meadow; California: San Louis Obispo Co., Cambria, 2.vii.1979 (DEW) 2 from Pinus radiata litter; Sacramento Valley, Jepson Prairie Reserve, 38°273N 121°825W, 13.iii.2009 (VBP, G. Pelletier) 4 from grassy area with Artemesia ; Kansas, Riley Co., Konza Prairie, 3.xi.1981 (T. Seastedt) 1 from annually burned prairie soil; Canada: Yukon: Kluane N.P., 2500ft. elv., 28.vii.1983 (J. Robinson) 6; Richardson Mountains, Brown shale hill on Fish Creek, 68°N, 136°32’W, 2.vii.1987 (VBP) 1 from Hedysarum alpinum, Senecio , Saxifraga tricuspidata among rocks; Ogilvie Mountains, Km 155 Dempster Hwy, Windy Pass, 7.vii.1985 (VBP) 7 from Salix and Anemone at edge of stream; British Columbia, Cathedral Provincial Park, Glacier Lake, 2210m elv., 5.vii.1986 (VBP) 1 from mixed alpine vegetation, some lupins; same location, but 2286m elv., 7.vii.1986 (VBP) 10 from Draba ventosa, Sedum lanceolatum and Polemonium on shale above lake; Alberta: W Cynthia, 53.20847, -115.65059, 2010, (ABMI 2010.OG-1175-1SW) 1 adult; S Gypsy Lake Wildland, 56.31538, -110.5361, (ABMI 2007.544 NW) 1 adult; S Chinook Valley, 56.43682, -117.65735, (ABMI 2007.616 SE) 1 adult; SE Grand Rapids Wildland, 56.50687, -112.16037, (ABMI 2009.539 NW) 1 adult; W Millennium Lodge, 56.86831, -111.96440 (ABMI 2007.477 NE) 1 adult; N intersection Hwys 60 and 13, 52.50389, - 110.73015, (ABMI 2008.1224 NW) 1 adult; nr. Bicentennial Hwy., S Vermillion Lake, 59.86996, -112.57944, (ABMI 2009.13 SW) 1 adult; midway between Nipisi airport and Wabasca airport, 55.85966, -114.63938, (ABMI 2008.689 SE) 1 adult; W Bistocho Lake, 59.81076, -119.45875, 13.vi.2014 (ABMI 69 SW) 5 adults; S junction Hwys 264 and 322, 51.73390, -113.64149, (ABMI 2013 OG-1383 SW) 2 adults; between Hwys 50, 45, 670, 55.20903, -118.61084, (ABMI 2007.544 NW) 1 adult; (ABMI 2013.835 SW) 2 adults; ABMI 2016.63 SW, 28.v.2016, 2 adults; ABMI 2015.OG-583 SW, 28.v.2015, 7 adults; ABMI 2016.122 NW, 29.v.2016, 3 adults; NW Embarras airport, 17.vi.2013 (ABMI 238 NE) 2 adults; 57.24687 -112.51016, 27.v.2012 (ABMI 415 SE), 8 adults; W Conklin airport, 55.68718 -111.44270, 25.v.2012 (ABMI 668 SE) 6 adults.

Revised diagnosis. Total length: 410–480. Longitudinal depressions ventrally extending from level of custodium to anal plate. Lamella about 104 long. Lamellar seta 17–20 long; mutual distance 20–26. Seta in about 20 long, smooth, acuminate; mutual distance 49–56. Bothridial seta fusiform, 90–94 long. Tutorium about 115 long, with distal tooth about 20 long, covering insertion of seta ro. Custodium tapered distally 3–5 long. Octotaxic system expressed as saccules, with Sa about 14 long, S1–S3 about 9 long.

Description. Adult. Total length: 410–480; holotype, 410 ( Hammer 1958); specimens from northern Canada considered conspecific by Hammer (1958), (n = 8) 440-460; total length based on specimens from California: females (n = 10) 469 (456–480); males (n = 3) 453 (448–456). Notogastral width females (n = 7) 309 (288–326); males (n = 1) 280.

Integument. Integument smooth; with longitudinal depressions ventrally extending from level of custodium to anal plate ( Fig. 10 ). Pteromorph, pedotectum I, gnathosoma , epimeres microtuberculate. Pedotectum I with fine striae along dorsal margin, pointed distally ( Fig. 13A ).

Prodorsum. Seta ro about 41 long, strongly barbed along length, acuminate, curved anteromedially ( Fig. 11 ). Lamella about 104 long, medially with V-shaped indentation; about 3 long. Lamellar seta arising anteriorly on fused lamella, just ventral of tip, 17–20 long; mutual distance 20–26. Seta in about 20 long, smooth, acuminate; mutual distance 49–56 ( Fig. 9 ). Bothridial seta fusiform, 90–94 long ( Fig. 9 ). Seta ex about 4, ( Fig. 11 ; often not evident, but alveolus present). Dorsophragmata fused at base, about 34 long ( Fig. 9 , arrow).

Lateral region of podosoma. Tutorium narrow tectum, about 115 long, with tooth distally, about 20 long, covering insertion of seta ro ( Figs. 11 , 13A ). Custodium tapered distally 3–5 long ( Fig. 10 ).

Notogaster. Notogaster slightly longer than wide: 1.2:1; anterior margin straight. Lenticulus present. Octotaxic system expressed as saccules ( Fig. 9 ), with Sa about 14 long, S1–S3 about 9 long, length difficult to measure, variable depending on orientation. Notogastral setae smooth, 15–23 long, setae subequal in length; lm usually medial and slightly posterior to Sa ( Fig. 9 ); lp medial to S1, dorsocentrally positioned.

Ventral. Epimeral setae mostly about 7–18 long, thin, smooth, acuminate, with 1c slightly barbed. Genital, aggenital, anal and adanal setae smooth; genital setae about 20, others about 11. Lyrifissure iad at anterolateral margin of anal plate. Postanal porose area about 36 long and 5 wide.

Gnathosoma . Small axillary saccule present at base of palp, 5 x 2 ( Fig. 13C ). Length of seta m>a>h.

Legs. Leg setal formulas I–IV, solenidia in parentheses: I: 1-5-3(1)-4(2)-20(2); II: 1-5-3(1)-4(1)-15(2); III: 2- 3-1(1)-3(1)-15; IV: 1-2-2-3(1)-12. Setae l” of genua and tibiae I and II thicker in shape than other setae on these segments, those of genua I and II strongly spinous ( Figs. 12A, B ). Seta pv” of tarsus II thick, strongly barbed ( Fig. 13D ). Tridactylous.

Description Immatures dimensions: Mean length (based on slide-mounted specimens): larva (n = 3) 265 (239– 288); protonymph (n = 1) 305; deutonymph (n = 2) 360, 436; tritonymph (n = 4) 473 (456–506). Length of prodorsal and hysterosomal setae given in Table 1.

Larva ( Fig. 14 ). Integument unsclerotized; tuberculate; that of hysterosomal venter more strongly tuberculate than dorsum. Hysterosomal setae borne on tubercles.

Prodorsum: Prodorsal setae, other than bothridial seta, all short, smooth, tapered; mutual distance of setae roro, le-le and in-in about 15, 24 and 35, respectively. Bothridial seta setiform, tapered distally.

Gastronotic Region: Tubercle posteriorly bearing setae dp largest of hysterosomal tubercles. Gastronotal setae of c, d, series and la, lm, h3 and h1, short, smooth, tapered; lp barbed, brush-like, blunt distally; h2, long, barbed, almost spinous. Mutual distance of setae da-da, dm-dm and dp-dp almost subequal, about 11–13.

Ventral Region: Medial margin of epimeral plates well defined. Epimere I with broad mentotectum, with medial edges well separated medially. Epimeral setae slightly barbed, isodiametric, about 8 long, except for scaliform seta 1c. Porose integument surrounding opening of opisthonotal gland not evident.

Protonymph ( Fig. 16C ). Integument: Unsclerotized with light brown coloration; bearing larval scalp in 3 of 4 specimens examined. Venter of hysterosoma strongly tuberculate; centrodorsal region of hysterosoma almost smooth (as for tritonymph Fig. 15 ). Setae of l and h series borne on large tubercles; seta dp borne on medial tubercle.

Prodorsum: Prodorsal setae, other than bothridial seta, all short, smooth, tapered; mutual distance of setae roro, le-le and in-in about 18, 18 and 40, respectively. Bothridial seta setiform, tapered distally.

Gastronotic Region: Tubercle posteriorly bearing setae dp ( Fig. 16B ). Gastronotal setae of c, d, series and la, lm, h1, h2, short, smooth, tapered; lp barbed, brush-like, blunt to rounded distally; h3 similar in shape to lp. Mutual distance of setae da-da, dm-dm and dp-dp, about 20, 23 and 10, respectively.

Ventral Region: Medial margin of epimeral plates well defined. Epimere I with broad mentotectum well separated medially. Epimeral, genital, aggenital and adanal setae very slightly barbed, isodiametric, about 8 long. Porose integument surrounding opening of opisthonotal gland not evident.

Gnathosoma: Axillary saccule present. Palpal eupathidium acm attached to solenidion along distal threequarters of solenidial length.

Deutonymph ( Figs. 16A, B ). Integument: Unsclerotized with light brown coloration; bearing larval and protonymphal scalps in 1 of 2 specimens examined. Hysterosoma strongly tuberculate, except for region of hysterosoma surrounding setae dm, dp almost smooth (as for tritonymph Fig. 15 ). Setae of l and h series borne on large tubercles; seta dp borne on medial tubercle.

As for protonymph, except for overall size. Setae ro le, in and ex tapered, smooth; Mutual distance of ro-ro, lele and in-in about 23, 24, and 54, respectively. Bothridial seta setiform, tapered. Gastronotal setae of c, d and p series and h1 smooth, tapered; other gastronotal setae brush-like, expanded distally. Centrodorsal region of hysterosoma shorter than in protonymph or larva.

Tritonymph. Integument: Unsclerotized with light brown coloration; bearing larval, protonymphal and deutonymphal scalps in 4 specimens examined. Hysterosoma strongly tuberculate, except for region of hysterosoma bearing d setae almost smooth ( Fig. 15 ). Setae of l and h series borne on large tubercles; seta dp borne on medial tubercle.

As for deutonymph, except for overall size. Mutual distance of ro-ro, le-le and in-in 24–30, about 31, and 49– 59, respectively. Bothridial seta setiform, tapered. Gastronotal setae of c, d and p series short, smooth, tapered; other gastronotal setae brush-like, expanded distally, and tapered. Centrodorsal region of hysterosoma shorter than in deutonymph, protonymph or larva (compare figs. 14, 15, 16B). Scalps forming triangular cap posteriorly on hysterosoma, with larval setae of d series closely adjacent at pinnacle of cap; triangular cap surrounded by cluster of brush-like l and h series setae ( Fig. 16D ).

Gnathosoma: Axillary saccule present. Palpal eupathidium acm attached to solenidion along distal threequarters of solenidial length.

Development. Development of epimeral setae (larva to adult): 3-1-2, 3-1-2-1, 3-1-2-2, 3-1-2-3, 3-1-3-3. Development of leg setae and solenidia given in Table 3. Proral setae of tarsus I eupathidial. Subunguinal seta of tarsus I of normal form and inserted proximal to antelateral pair as in adult. Porose areas present on femora I to IV. Setae d on genua and tibiae, other than tibia I, short, setiform, about 6 long, subequal in length to companion solenidia. Solenidion and coupled seta d on tibia I on anterodorsal tubercle. All solenidia, other than φ1 on tibia I very short, baculiform, about 4–6.

Remarks. 1. Hammer (1958) described this species based on a single specimen (body length 410) from “a thick carpet of moss with a little Juncus between big tussocks grass” in Argentina. I applied to borrow the holotype from the National History Museum, Denmark, but the specimen housed in the appropriate vial was an adult of Hermanniella , and there is no other record of the whereabouts of the type. Marshall et al. (1987) list it as being unknown. Hammer (1958) described it as being smaller than T. latirostris , and differing in the prodorsum and position of the saccules. Tegoribates americanus has interlamellar setae, which are supposedly absent in T. latirostris ( Coggi 1900, Kunst 1959). Hammer (1958) considered her previous records of T. latirostris from northern Canada (body length 440–460; Hammer 1952) to instead represent T. americanus . Hammer (1958) did not comment on specimens she identified as T. latirostris from Fairbanks and Anchorage, Alaska ( Hammer 1955), but the body lengths she gave for these specimens (n = 8) 473 (440–510) accord with those for T. americanus , and this misidentification was noted, along with those from northern Canada, in Marshall et al. (1987). In turn, Hammer (1955) was the basis for the identification of T. latirostris from the Brooks Range, Alaska by Thomas and McLean (1988; see their Acknowledgements).

2. Hammer (1958) described genua I, II and IV with “sharp spine distally which in its natural position points outwards when the leg is bent”; this is seta l” on genua I and II and l’ on genu IV, the thickest setae on these segments. Seta l” of genu II is more spine-like than l” on genu I and l’ on genu IV, and strongly projects laterally ( Figs. 19F , insert, 21A, C, D).

3. Behan-Pelletier (2001) incorrectly referred to immatures of this species as apopheredermous. They, and those of other known immatures of Tegoribates are eupheredermous, specifically “Euphérédermes à nymphes intégridorsales”, that is they retain the centrodorsal setae of the d series, but do not use these setae to attach scalps ( Grandjean 1958).

4. Gut contents of adults and immatures included fungal hyphae, spores and undetermined material. Gravid females carry 2 eggs.

Figures

FIGURE 9. Tegoribates americanus Hammer, adult female, dorsal aspect, legs not illustrated, with arrow to fused dorsophragmata. Scale bar = 50 µm.

FIGURES 10 – 11. Tegoribates americanus Hammer, adult female, legs removed; 10, ventral aspect; 11, lateral aspect of prodorsum and podosoma, gnathosoma removed, with arrow to taenidium. Scale bar = 50 µm.

FIGURE 12 A – C. Tegoribates americanus Hammer, adult female, legs, all antiaxial aspect (trochanter not shown in A, B): A, leg I, with arrow to bend in femur; B, leg II (femur to tibia), C, leg III. Scale bar = 20 µm.

FIGURE 13. Tegoribates americanus Hammer, differential interference contrast microscope images of adult. A, lateral of prodorsum (6 layers) with arrows to taenidium; B, bothridial seta and bothridium, with arrow to anterior scale; C, chelicera, pedipalp and rutellum showing size relationship, supracoxal seta e, and with arrow to axillary saccule (5 layers); D, tarsus II, showing shape of seta pv ”; E, postanal porose area. Scale bars: A, B = 50 µm; C = 25 µm.

FIGURE 14. Tegoribates americanus Hammer, larva, dorsal aspect. Scale bar = 50 µm.

FIGURE 15. Tegoribates americanus Hammer, tritonymph, dorsal aspect, scalps removed. Scale bar = 50 µm.

FIGURE 16. Tegoribates americanus Hammer, differential interference contrast microscope images of immatures from permanent slide mounts. A. deutonymph lateral aspect (5 layers), bearing closely adpressed larval and protonymphal scalps (scalps partially pulled away), with inserts showing larval and protonymphal seta dp, (area of attachment for scalp), and distinct projection around setae dp; B, protonymph, dorsal aspect (2 layers), bearing larval scalp; C, protonymph, lateral aspect, showing projection formed by tubercle bearing setae dp; D, tritonymphal scalp showing cluster formed by setae of l and h series. Scale bars: A, B = 50 µm; C = 25 µm.

FIGURE 19. Tegoribates bryophilus Woolley, differential interference contrast microscope images of adult type material. A. anterior of prodorsum (note, specimen broken), with arrow to taenidium; B, pteromorph; C, saccule Sa and seta lm; D, posterior of prodorsum with arrow to fused dorsophragmata (3 layers); E, lateral of coxisternal region showing circumpedal carina and discidium; F, lenticulus; G, seta l ” of genu II. Scale bars: A, B, E = 50 µm; C, = 10 µm; D = 35 µm.