Amerozercon auricularis, Ujvári, 2013

Ujvári, Zsolt, 2013, Amerozercon Halašková, 1969 species (Acari: Mesostigmata: Zerconidae) of the United States of America, Journal of Natural History (J. Nat. Hist.) 47 (15 - 16), pp. 1093-1120 : 1105-1108

Amerozercon auricularis sp. nov.

( Figures 2I and 6A, B )

Material examined ( Figure 3 )

Holotype: female, USA, California, Plumas County, Warner Creek, 1525 m above sea level, 12.8 km northwest of Chester , from cottonwood litter, 30 July 1985, leg. E.E. Lindquist. Holotype is deposited in CNC (coll. number: CNCAZ0603 ) .

Diagnosis

Anterior margin of ventrianal shield with two pairs of setae (setae Zv1 present). Central podonotal setae, s1, r1, J-setae, Z1–2, S2 and R2–7 short and smooth, other dorsal setae feathered. Third pair of opisthonotal pores (Po3) absent. Dorsal cavities well sclerotized and of different size, the central pair larger, auricle-shaped. Podonotum covered by tile-like pattern, anterior surface of opisthonotum bearing netlike ornamentation with refracting dots at the connecting points, posterior surface with alveolar pits.

Description – female

Length of idiosoma: 328 µm; width: 231 µm (n = 1). Dorsal side ( Figure 6A ). Podonotum with 20 pairs of setae, j1–6, z2–6, s1–6, r2 and r4–5 inserted dorsally, r1 and r3 inserted ventrally, on peritrematal shields (see at ventral side). Marginal setae of podonotum (z3, s2, r2, s3, r4, r5, s6) and j1–2 feathered, other podonotal setae smooth and needle-like. Setae j2, z2, s3, r5 and s6 markedly longer than central setae. Glands gds1 (po1) situated anteromedially to s1; gdj4 (po2) situated anteromedially to z4; gds4 (po3) on line connecting s4 and s5, near s4. Whole surface of podonotum covered by tiles possessing undulate posterior margins.

Opisthonotum with 22 pairs of setae, J1–5, Z1–5, S1–5, R1–7. Each J-seta short (their length increasing posteriorly), smooth and needle-like, none of them reaching bases of the following one in the series. Setae J1–4 constitute parallel rows, setae J5 inserted somewhat lateral to these rows, near the anterolateral margin of central dorsal cavities. Setae Z1–2 and S2 short, smooth and needle-like. Setae S2 situated slightly below the line connecting Z1 and S1, somewhat nearer to Z1. Setae Z3–5 and S3–5 elongate, feathered, Z4 and S3–5 expanding beyond the margin of opisthonotum. Among marginal setae S1 approximately as long as S2, but feathered, R1 barbed. Remaining R-setae smooth and pointed, their length decreasing posteriorly. Length of opisthonotal setae and distances between their insertions as in Table 4. Glands gdz6 (Po1) situated anterolaterally to insertions of Z1; gdZ2 (Po2) laterally to Z2; third pair of opisthonotal pores (Po3) absent; gdS5 (Po4) on line connecting S5 and Jv5, near Jv5.

bases in Amerozercon auricularis sp. nov.

Marginal serration shallow and obtuse. Anterior surface of opisthonotum (to level of setae J3-Z3-S3) bearing net-like ornamentation with refracting dots at the connecting points, posterior surface with small to medium sized alveolar pits. Dorsal cavities wellsclerotized and of different size. Lateral pair small, saddle-like, with undulate margins and axes converging anteriorly. Central cavities significantly larger, auricle-shaped, with axes converging posteriorly.

Ventral side ( Figure 6B ). Shape of peritrematal shields and peritrematal setae typical for the genus. Peritremes nearly straight, with a small dilatation near the stigma. On the shield only a few arcuate lines can be observed near the peritrematal pore. Sternal shield well sclerotized, 65 µm long and 48 µm wide at the level of setae st2, with concave posterior margin and reticulate ornamentation. Adgenital glands gv2 with two openings on the right side and with three openings on the left side of the single specimen. Ventrianal chaetotaxy complete, setae Zv1 present. Postanal seta elongate and smooth, preanal and adanal setae short, smooth and needle-like. Setae Jv5 elongate, feathered. Anal valves with vestigial euanal setae. Glands gv3 situated anterolaterally to adanal setae. Anterior surface of ventrianal shield covered by squamous pattern to level of adanal setae and Jv4.

Gnathosoma

Situation of hypostomal and subcapitular setae typical for the family. Setae h1 elongate, needle-like. Setae h2–3 shorter than h1, needle-like, h4 longer than previous setae, serrate. Corniculi horn-like, internal malae with a pair of bifurcate anterocentral branches and with serrate margins. Chelicerae relatively slender, fixed digit with six teeth, movable digit with four or five teeth. Epistome ( Figure 2I ) typical for the genus Amerozercon , of Zercon - type (see Ujvári 2011b).

Male and immature stages

Unknown.

Etymology

The name of the new species refers to the auricle-shaped central dorsal cavities (the Latin epithet “ auricularis ” means auricular).

Remarks

The new species corresponds in many diagnostic characteristics (e.g. shape of peritrematal setae, number of R-setae, presence of gland openings gv2, situation of gv3) with the genus Amerozercon . Altough male specimens have not been found yet (which carry one of the most important character of the genus), the absence of the third pair of opisthonotal pores (Po3) and the different size and shape of dorsal cavities also suggest that the species is related to the type-species, A. suspiciosus Halašková, 1969 , therefore A. auricularis sp. nov. is placed in the genus Amerozercon . It is important to note that the R-setae of the new species are smooth and pointed, which distinguishes it from the previously known Amerozercon species , but this should not be used as a feature that is appropriate to characterize genera.

The short, smooth J- and R-setae, the elongate, feathered S3–5 and Z3–5 setae and the auricle-shaped central cavities are unique characters within the genus.

Figures

Figure 2. Different structures of Amerozercon species. (A–C) Epistomes of Amerozercon minimus females; (D, E) epistomes of Amerozercon suspiciosus females; (F) chelicera of A. suspiciosus male; (G, H) epistomes of Amerozercon annularis sp. nov. females; (I) epistome of Amerozercon auricularis sp. nov. female; (J) epistome of Amerozercon halaskovae sp. nov. female;

Figure 3. Occurrences of Amerozercon species.

Figure 6. Amerozercon auricularis sp. nov. female. (A) Dorsal view; (B) ventral view.