Acanthococcus kemptoni

Acanthococcus kemptoni (Parrott) rev. comb.

Eriococcus kemptoni Parrott 1900: 144.

Nidularia kemptoni (Parrott); Lindinger 1933a: 116 (change of combination).

Eriococcus mancus Ferris 1955: 138. (junior synonym discovered by Miller & Miller 1992: 51-54). Notes: The type material of Eriococcus mancus Ferris is misidentified specimens of Eriococcus kemptoni.

Acanthococcus kemptoni (Parrott); Miller and Miller 1992: 51–54 (change of combination).

Rhizococcus kemptoni (Parrott); Kozár 2009: 109. (change of combination).

Specimens examined: material not reported previously: UNITED STATES: Georgia: Fulton Co.: Ft. Mc Pherson, VI-4-1943, on Andropogon virginicus, H.S. McConnell (4 ad. ♀♀, 2 embryonic first-instar nymphs and 40 firstinstar nymphs on 2 slides) USNM. Kansas: Barber Co.: 10 mi. N. Medicine Lodge, VI-28-1970, on grass, tended by Formicidae, Crematogaster punctulata, D.R. Miller (5 second-instar ♀♀, 3 first-instar nymphs on 1 slide) USNM; Butler Co.: Douglass, VI-28-1970, on grass, D.R. Miller (10 first-instar nymphs on 1 slide) USNM. Virginia: independent city in Commonwealth of Virginia, 7 mi. E. Fredericksburg, III-15- 1971, V-7-1971 and VII-17-1971, on A. virginicus, S. Nakahara and D.R. Miller (41 first-instar nymphs on 4 slides) USNM.

Etymology: The species epithet “ kemptoni ” is named in honor of one of the original collectors (R.H. Kempton) from Kansas.

Field features: Occurring on grass leaf blades.

Second-instar female (Fig. 12)

Description: Slide-mounted specimens 1.1–1.2 mm long, 0.5–0.6 mm wide. Body elongate, with protruding anal lobes. Anal lobes apically acute, lightly sclerotized; each lobe dorsally with 3 elongate, apically rounded enlarged setae, all about same length; each lobe ventrally with 3 flagellate setae including anal-lobe seta and 2 or 3 multilocular pores.

Dorsum without flagellate setae. Enlarged setae forming 3 or 4 pairs of longitudinal lines (medial, mediolateral, sublateral and lateral); enlarged setae of 2 sizes: larger size along body margin on segments IV to VIII and on head, with 2 on each margin of each abdominal segment; smaller size in medial, mediolateral and sublateral areas; largest lateral enlarged setae each about 38 μm long; largest small-sized setae each about 8 μm; longest lateral seta 4–5 times longer than longest medial seta; lateral setae straight or slightly curved, slender, with rounded apices; medial setae straight, short, with blunt apices; setal rings thin; segment IV with 9–11 setae. Microtubular ducts absent. Multilocular and cruciform pores absent. Microtrichia present on segments II to VIII.

Anal ring apical, with 3 setae on each side of ring, suranal setae flagellate. Anal tube without sclerotization.

Venter with longest seta on segment II about 18 μm long; longest on segment VII about 20 μm; anal-lobe seta about 310–330 μm long. Enlarged setae of small size only, present in lateral and sublateral areas of head, thorax and anterior abdominal segments. Microtubular ducts absent. Multilocular pores of 2 kinds: 5-locular pores scattered over head and thorax, present mediolaterally on abdomen; 7-locular pores common, 5-locular pores most abundant. Cruciform pores variable, present laterally and sublaterally on head, thorax, and anterior abdominal segments, sometimes scattered in medial areas of thorax and abdomen. Legs with hind coxae with 2 or 3 indefinite pores on dorsal surface; hind 2 pairs of tibiae each with 4 setae, without seta in middle of tibia, front tibiae each with 5 setae, with 1 seta in middle of tibia; hind tibia/tarsus 0.7–0.9. Antennae each 6-segmented, about 190 μm long. Frontal lobes absent; preantennal pore present. Microtrichia present on mesothorax to segment VIII.

Notes: The description is based on five specimens from one locality. The presence of two large-sized enlarged setae on each lateral margin of segments IV to VIII and also on the head, but not on the remaining part of the lateral head, thorax, and anterior abdomen, is unique for the second-instar female of Ac. kemptoni. It also is distinctive in having five setae on each front tibia but only four on each hind tibia. For a comparison of this species with Ac. hoyi see the “Notes” section of the second-instar female of that species.

First-instar nymph (Figs 13 and 14)

Description: Slide-mounted specimens 0.6–1.0 mm long, 0.3–0.5 mm wide.Body elongate oval, with protruding anal lobes. Anal lobes broad, apically rounded, slightly sclerotized; each lobe dorsally with 3 apically enlarged setae with apices narrowly rounded, all setae about same length, without microtubular ducts; each lobe ventrally with 3 flagellate setae including suranal seta and elongate anal-lobe seta.

Dorsum without flagellate setae. Enlarged setae forming 3 pairs of longitudinal lines on abdomen (medial, mediolateral and lateral), less obvious on thorax and head; enlarged setae of 2 sizes: larger size along body margin on segments II, III, or IV to VIII and on head, with 1 present on each margin of each abdominal segment; smaller size in medial and mediolateral areas; largest lateral enlarged setae 33–35 μm long; largest small-sized setae each about 8 μm; longest lateral seta 4–5 times longer than longest medial seta; lateral setae straight or slightly curved, slender, with rounded or pointed apices; medial setae straight, short, with blunt apices; setal rings thin; segment IV with 6 setae. Microtubular ducts rare or absent. Multilocular and cruciform pores absent. Microtrichia present on segments II to VIII. Cauda present.

Anal ring apical, with 3 setae on each side of ring, suranal setae flagellate. Anal tube without sclerotization.

Venter with setae flagellate, longest seta on segment II 13–19 μm long, longest seta on VII 10–18 μm long; longest anal-lobe seta about 250 μm long. Small-sized enlarged setae present laterally on most anterior abdominal segments; macrotubular ducts and microtubular ducts absent. Multilocular pores all 5-locular, present near base of antenna, near each spiracle, and mediolaterally on 1 or more abdominal segments, sometimes present near mouth parts. Cruciform pores present along lateral margin of thorax and anterior abdomen, with 3 such pores on each body margin. Legs without pores; each femur with 5 setae; hind tibiae each with 4 setae, without seta in middle of hind tibia; front tibiae each with 5 setae, with seta in middle of tibia; hind tibia/tarsus 0.7. Antennae each 6-segmented, 140–150 μm long. Frontal lobe absent; preantennal pore present. Microtrichia present on mesothorax to segment VIII.

Notes: For an explanation of the transfer of Rhizococcus kemptoni from Rhizococcus to Acanthococcus, please see the Introduction and “Notes” on Ac. coccineus above; we are reinstating the assignment of this species to the widespread genus Acanthococcus.

The description is based on 131 first-instar nymphs and two embryos from three localities. For a comparison of the first-instar nymph of Ac. kemptoni with the first-instar nymph of Ac. hoyi, see the “Notes” section of that species.