Acanthococcus Signoret 1875

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, Zootaxa 5221 (1), pp. 1-213 : 12

Acanthococcus Signoret 1875

Acanthococcus Signoret 1875: 16 . Type species: Acanthococcus aceris Signoret 1875 by monotypy.

Atriplicia Cockerell and Rohwer 1909: 169 syn. n. Type species: Atriplicia gallicola Cockerell and Rohwer 1909 by monotypy.

Generic diagnosis of adult female: Enlarged setae usually abundant on dorsum, but some species with setae restricted to all or part of body margin; anal lobes generally large and protruding, each with 1 or more enlarged setae, usually 3; macrotubular ducts present on adult female and second-instar male; microtubular ducts present, usually associated with enlarged setae; multilocular pores present at least on venter, usually each with 5 loculi; cruciform pores usually present; translucent pores present on hind legs of adult female and second-instar female, usually on femur and coxa; anal ring usually with 4 pairs of setae and 1 or 2 rows of pores; each femur usually with 5 setae; each tibia usually with 4‒6 setae; claw with denticle; digitules on tarsus and claw usually capitate; antennae 6- or 7-segmented, with sensory setae on distal 3 segments; labium 3-segmented, basal segment small, with 2 setae.

Notes: For an explanation and a list of the 20 Nearctic species transferred from Eriococcus to Acanthococcus in this work, please see the Introduction above.

In North America, adult females of the species in Acanthococcus are most similar to adult females of species of Ovaticoccus but differ as follows (character states of Acanthococcus are in brackets): anal ring normally with three or fewer pairs of setae (with four pairs of setae); anal lobes not protruding or protruding slightly, inconspicuous (protruding strongly, conspicuous); without frontal lobes (with or without frontal lobes); translucent pores usually on hind coxa only (on hind femur and coxa). Species of Acanthococcus also are similar to the Australasian and Neotropical genus Madarococcus Hoy 1962 ( Hardy et al. 2008) but differ as follows (character states of Acanthococcus in brackets): suranal seta expanded (suranal seta flagellate); anal lobes large and almost plate like, heavily sclerotized (anal lobes not plate like, usually slightly sclerotized).

Etymology: The generic epithet “ Acanthococcus ” is a combination of the Greek word “ akantha ” meaning spine or thorn, and “ kokkos ” meaning “seed” or “scale insect” and is a masculine noun. The generic epithet is formed to point out the enlarged setae on the dorsum of many species of the genus.

Field features: Body usually pear-shaped, with various arrangements and shapes of crystalline wax rods formed on the enlarged setae; forming white felted ovisac that covers body, with small posterior exit hole. Occurring on most parts of host including roots, crown, branches, and leaves, rarely inducing galls.

Key to Acanthococcus species treated here, based on first-instar nymphs

1(0) Each hind tibia with 5 setae, including middle seta.......................................................... 4

– Each hind tibia with 4 setae, without middle seta............................................................ 2

2(1) Each front tibia with 4 setae, without middle seta; medial enlarged setae on dorsum of abdomen as large as largest lateral setae............................................................................................... 3

– Each front tibia with 5 setae, with middle seta; medial enlarged setae on dorsum of abdomen smaller than largest lateral setae..................................................................................... kemptoni (Parrott)

3(2) Multilocular pores near spiracles each often with 7 or 9 loculi; multilocular pores on abdomen predominantly each with 5 loculi; cruciform pores present on ventral margin of thorax................................. dennoi Miller and Miller

– Multilocular pores near spiracles each with 5 loculi; multilocular pores on abdomen predominantly each with 3 loculi; cruciform pores absent from ventral margin of thorax....................................... pennyae Miller and Stocks sp. n.

4(1) Hind femora each with 5 setae.......................................................................... 5

– Hind femora each with 4 setae......................................................... coccineus (Cockerell)

5(4) Margin of each abdominal segment with 1 enlarged seta...................................................... 6

– Margin of each abdominal segment with 2 enlarged setae.................................... hoyi Miller and Miller

6(5) Medial and mediolateral enlarged setae on dorsum of abdomen about same size as lateral setae; cruciform pores absent.............................................................................. gallicolus (Cockerell & Rohwer)

– Medial and mediolateral enlarged setae on dorsum of abdomen smaller than lateral setae; cruciform pores usually present near ventral margin of thorax............................................................... arenosus (Cockerell)