Acanthococcus arenosus Miller & Stocks 2022, comb. n.
Creators: name: Miller, Douglass R.
name: Stocks, Ian C.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Eriococcidae
Acanthococcus
Acanthococcus arenosus

description: Acanthococcus arenosus (Cockerell) comb. n.
Eriococcus arenosus Cockerell 1897: 514.
Acanthococcus arenosus (Cockerell); Miller 1991: 334 (change of combination).
Specimens examined: UNITED STATES: New Mexico: Rio Arriba Co.: Embudo, IX-26-1897?, host unknown, T.D.A. Cockerell? (35 first-instar nymphs on 1 slide) USNM.
Etymology: The species epithet “ arenosus ” is formed from the Latin word “ arena” meaning “sandy place” and probably refers to the sandy habitat where this species often occurs.
First-instar nymph (Fig. 3)
Description: Slide-mounted specimens 0.4–0.6 mm long, 0.2–0.3 mm wide. Body slightly pear-shaped, with protruding anal lobes. Anal lobes broad, apically acute, lightly sclerotized; each lobe dorsally with 3 enlarged setae (anteromedial seta normally shortest, posteromedial and lateral setae equal, sometimes all setae about equal), 1 microtubular duct, each lobe ventrally with 3 flagellate setae including suranal seta and anal-lobe seta.
Dorsum without flagellate setae; enlarged setae arranged in 3 pairs of longitudinal lines (medial, mediolateral and lateral) in transverse rows from head to segment VII; enlarged setae of 2 sizes; larger size along body margin, with 1 on each margin of each abdominal segment, more numerous on head and thorax; smaller size in medial and mediolateral areas, largest large-sized setae 13–15 μm long, largest small-sized setae 7–9 μm, longest lateral seta about 2 times longer than longest medial seta; lateral setae slightly curved, conical, with slightly rounded apices; medial setae straight, conical, with blunt or rounded apices, increasing in size anteriorly; setal rings thin; segment IV with 5 or 6 setae. Macrotubular ducts absent. Microtubular ducts each with area farthest from dermal orifice sclerotized and divided into 2 parts, apical portion rounded and about ½ length of remaining sclerotized portion; total sclerotized area same length as or longer than unsclerotized area; dermal orifice unsclerotized. Microtubular ducts on abdomen associated with mediolateral pairs of enlarged setae, forming 1 pair of longitudinal lines; on thorax and head, microtubular ducts associated with medial or mediolateral and lateral pairs of enlarged setae, forming 2 pairs of longitudinal lines. Multilocular and cruciform pores absent. Microtrichia present on segments II to VII.
Anal ring apical, with 3 setae on each side of ring, suranal setae flagellate, slightly enlarged. Anal tube without sclerotization, with anal flap.
Venter with longest flagellate seta on segment II 10–15 μm long, on segment VII 24–32 μm long; longest anallobe seta 170–220 μm long. Enlarged setae on lateral margins from head, thorax, or anterior segments to segment VII, conical. Macrotubular ducts absent. Microtubular ducts absent. Multilocular pores of 2 kinds: 5-locular pores usually present on head and near spiracles; 3-locular pores most numerous, present elsewhere; with 1 pore on each side of head, 1 near medial areas of hind and middle coxae, 1 near each spiracle, and in irregular mediolateral longitudinal line on each side of abdomen. Cruciform pores sometimes present adjacent to mid- and hind coxae. Legs with each femur with 5 setae including 2 proximal setae; each tibia with 5 setae, 1 seta in middle; hind tibia/ tarsus 0.7–0.8. Antennae each 6-segmented, 128–145 μm long. Frontal lobes absent. Preantennal pore present. Microtrichia present in medial areas of metathorax to VIII, absent from coxae.
Notes: The description is based on 38 specimens from the type locality. The first-instar nymph of Ac. arenosus is most similar to the first-instar nymph of Ac. coccineus in having the dorsal medial and mediolateral enlarged setae noticeably smaller than the lateral enlarged setae, the predominant multilocular pores with three loculi, and the ventral lateral enlarged setae increase in size anteriorly. The species differ as follows (character states in brackets are of A. arenosus): dorsomedial and mediolateral enlarged setae cylindrical (predominantly conical); each femur with five setae (each femur with four setae).
description: Published as part of Miller, Douglass R. & Stocks, Ian C., 2022, New genera and species of felt scales (Hemiptera: Coccomorpha: Eriococcidae), with descriptions of new species and immature instars of described species, pp. 1-213 in Zootaxa 5221 (1) on page 13, DOI: 10.11646/zootaxa.5221.1.1, http://zenodo.org/record/7441371