Autogneta amnica Jacot, 1938

Behan-Pelletier, Valerie M., 2015, Sexual dimorphism in Autogneta, with description of three new species from North America and new diagnosis of the genus (Acari, Oribatida, Autognetidae), Zootaxa 3946 (1), pp. 55-78 : 58-61

Autogneta amnica Jacot, 1938

Figs 1–9

Autogneta longilamellata amicus Jacot, 1938 , p. 11 Autogneta amica Jacot, 1938 , Banks (1947, p. 122)

Material Examined. Cotypes: USA, North Carolina, Buncombe Co., Poplar Cove, Bent Creek Experimental Forest, 35.488°N, 82.624°W; 1.vii. 1935 (A. P. Jacot), 25 specimens (21 females and 4 males) from fern litter, on slide 35F5.3–9 ( USNM); same data, but 35F6.3–9 (not labelled cotype), 1 female (RAN). New York, Cortland Co., Heiberg Memorial Forest, 43.035°N, 76.135°W, 15.v.1971 (R. A. Norton) 1 female from humified log in hardwood forest; Alabama, De Kalb Co., De Soto State Park, Rhododendron Trail, 34.501°N, 85.618°W, 27.ix.1992 (V. Behan-Pelletier) 2 females, 2 males from moss at base of hemlock; Virginia, Blue Ridge Parkway, Washington National Forest, Wintergreen Trail, 37.930°N, 78.952°W, 1.x.1992 (V. Behan-Pelletier) 1 female, 1 male from in and under decaying tree trunk in oak-hemlock forest. Canada, Ontario, Eganville, Shaw Woods Nature Preserve, 45.667°N, 77.267°W. 20.v.1993 (B. Eamer) 2 males from second-growth forest.

Diagnosis. Adult. Apophyses posteriorly on prodorsum expressed as 1 pair of narrow, discrete ridges. Circular cluster of tubercles anterolateral of lamellar seta. Bothridial seta 44–51, with fusiform head about 21, head with minute spicules, except 1 longer spicule distally. Cluster of tubercles posterior of acetabulum IV. Genital setae 6 pairs. Leg segments without tubercles. Femur I without tubercles on proximal third of leg. Genua I and II with seta v’ present. Notogastral setae c and l series thin, very weakly barbed, acuminate, 16–19 long, with c shortest seta. Sexually dimorphic, with males having oblong porose area posteromedially between lyrifissures ips, setal pair h1 inserted within porose area. Seta h1 longer (24–31) than in female and thick, heavily barbed, acuminate. Pair h1 more closely adjacent in male, mutual distance h1–h 1 8–12; in female h1–h 1 27–31.

Description. Adults. Dimensions: Total length: cotype females (n = 9) 280 (259–288); females (Virginia) (n = 2) 293 (293, 293); cotype males (n = 3) 255 (243–273); males (Virginia) (n = 1) 283. Notogastral length: females (n = 2) 197 (192, 202).

Integument: Generally microtuberculate. Pleural region strongly tuberculate from dorsal of acetabulum II to acetabulum III ( Fig. 4 ). Circular cluster of tubercles lateral of lamellar seta ( Fig. 7 , white arrow). Cluster of tubercles posterior of acetabulum IV ( Fig. 6 , arrow). Leg segments without tubercles; ridges present antiaxially on femur IV. Margin of epimere 4 without concave depressions medially ( Fig. 6 ).

Prodorsum: Rostral incision about 15. Costula 66–86, medial and lateral edges roughened; bearing seta le anteriorly, about 27 long, acuminate, barbed ( Figs 1 , 4, 7 ); longitudinal ridge and tubercles absent lateral of costula; transverse ridge present associated with anterior tubercle of enantiophysis E ( Fig. 7 , black arrow). Enantiophysis E well developed lateral to proximal third of costula ( Figs 1 , 7 ). Region lateral of lamellar seta smooth, defined by transverse ridge of enantiophysis E posteriorly and anterolateral circle of tubercles anteriorly ( Figs 4, 7 , arrows). Apophyses posteriorly on prodorsum expressed as 1 pair of narrow, discrete ridges ( Figs 1 , 4, 5 ). Rostral, lamellar, interlamellar and exobothridial setae thin, weakly barbed, acuminate; ro 19–27, le 22–27, in 12–18, ex about 17. Mutual distance ro–ro about 15, le–le 17–21, in–in about 26. Humeral apophysis weakly developed ( Figs 1 , 4 ). Bothridial seta 44–51, with fusiform head about 21, head with minute spicules, except 1 longer spicule distally ( Figs 4, 5 ).

Notogaster: With U-shaped furrow clearly evident ( Fig. 1 ). In female, notogastral setae thin, very weakly barbed, acuminate, 16–19 long, with c shortest seta, positioned as in Fig. 1 ; mutual distance h1–h 1 27–31, that of p1– p 1 26–37. Males with oblong porose area posteromedially positioned between lyrifissures ips, 27 wide x 19, and bearing seta h1 ( Figs 8, 9 , arrows). Notogastral setae of males similar to those of female, except h1 setae longer than in female, 24–31 and thick, heavily barbed, acuminate ( Figs 3 , 8, 9 ); mutual distance h1–h 1 8–12, p1–p 1 27–31.

Ventral Region: Epimeral setae 11–19 long, tapered, slightly roughened, with seta 3b longest. Genital setae 6 pairs, about 8 long, acuminate, smooth, positioned as in Figs 2 , 6 ; aggenital and anal setae 12–15 long, smooth, acuminate. Adanal setae weakly barbed, 12–23.

Gnathosoma: As for genus.

Legs: Setation ( Table 1 ): leg I: 1-5-3(1)-4(2)-18(2); leg II: 1-5-2(1)-4(1)-15(2); leg III: 2-3-1(1)-3(1)-15; leg IV: 1-2-2-3(1)-12. Femur I without antiaxial or dorsal tubercles in proximal third. Seta v ’ present on genua I and II.

Immatures: Unknown.

Remarks. This species was described as a subspecies of Autogneta longilamellata by Jacot 1938. Banks (1947) redescribed the species and considered it a distinct species; as did Marshall et al. (1987) and Subías (2004, 2014). Sexual dimorphism in this species is clearly distinct from that in A. longilamellata (see below).

Both males and females of this species are easily recognized by the circular patch of tubercles anterolaterally on the prodorsum, and the pair of narrow, discrete ridges posteriorly on the prodorsum. Sexual dimorphism in this species is expressed as males with an oblong porose area posteromedially positioned between lyrifissures ips, which is absent in the female and setae h1 longer in the male than in the female, and thick, heavily barbed, and acuminate.

Gravid females carry up to 2 large eggs. Gut contents are primarily darkly pigmented fungi.

Figures

FIGURES 1 – 3. Autogneta amnica Jacot. 1, adult female, dorsal aspect, legs not illustrated, except for proximal segments of leg I and II; 2, adult female, ventral aspect from genital plate posteriorly; 3, adult male, ventral aspect of posterior region. Scale bar = 50.

FIGURES 4 – 9. Autogneta amnica Jacot. Differential interference contrast microscope images of adults: 4, male, prodorsum and anterior of notogaster, cluster of tubercles anterolaterally indicated by arrow (2 layers combined); 5, female, prodorsum (arrow to posterior apophysis) (4 layers combined); 6, male, posterior of coxisternum and genital plate, arrow to cluster of tubercles posterior of acetabulum IV (3 layers combined); 7, male, prodorsum, white arrow to cluster of tubercles anterolaterally, black arrow to transverse ridge from anterior apophysis of enantiophysis E (3 layers combined); 8, male, posterior of notogaster, arrow to porose area (4 layers combined); 9, male, posterior of notogaster, porose area indicated by arrow (2 layers combined). Scale bar: 4 – 8 = 20, 9 = 10.

Tables

TABLE 1. Setiform organs in adult Autogneta amnica Jacot. Setae (Roman) and solenidia (Greek) are indicated; parentheses indicate pairs of setae.

	Trochanter	Femur	Genu	Tibia	Tarsus
Leg I	v’	d bv” (l) v’	σ (l) v’	φ 1 φ 2 (l) (v)	(ft) (tc) (p) (u) s (a) (pv) (pl) (it) e ω 1 ω 2
Leg II	v’	d, bv” (l) v’	σ (l) v ’	φ (l) (v)	(p) (tc) (ft) (u) s (a) (pv) ω 1 ω 2 (it)
Leg III	v’ l’	d ev’ l’	σ l’	φ (v) l’	(p) (tc) (ft) (u) s (a) (pv) (it)
Leg IV	v’	d ev’	d l’	φ (v) l’	(p) ft” (u) (pv) (tc) (a) s