Acanthococcus haywardi Juarez & Gonzalez, sp. nov.

Acanthococcus haywardi Juárez & González sp. nov.

(Fig. 1)

Type material. Holotype: adult female placed towards the right of the slide, marked with a red circle. Argentina, Santiago del Estero, Park (27°46'54" S, 64°15'2" W), on Acacia caven, -/ XI/1943, Hayward col. 1(2) (IFML).

Species diagnosis, adult female. Dorsal setae each conical with an acute apex; macrotubular ducts symmetrical and very large. Margin with 2 setae on each abdominal segment and on metathorax. Ventral surface with enlarged conical setae absent; microtubular ducts absent; quinquelocular, trilocular and cruciform pores sparse; metathoracic coxa with about 50 pores; metathoracic tibia with 4 setae and prothoracic tibia with 5 setae.

Description. Slide-mounted adult female: body oval, 1.20 (1.10) mm long, 0.80 (0.88) mm wide. Anal lobes elongated, each 62 (60) µm long, 45 (43) µm wide, with 3 dorsal conical setae of different lengths: anterior inner seta 31 µm, posterior inner seta 52 µm and outer seta 38 µm long; each lobe also with two flagellate ventral setae, anterior seta 22 µm and posterior seta 31 µm long (setae not visible on paratype specimen). Medial plate absent.

Dorsal surface: conical setae each straight or slightly curved with an acute apex, smaller than those on margin, sizes varying from 15–35 (17–31) µm long, larger setae located in cephalic region and smaller setae in lines one or two wide, parallel to intersegmental lines; present over entire surface. Macrotubular ducts symmetrical and very long, each about 34 (29) µm long, 5 (5) µm wide, distributed throughout. Microtubular ducts of both type A and B present, sparse, scattered throughout. Anal ring with 8 setae, each about 72 (72) µm long, plus a single row of pores.

Margin: conical setae present around entire margin, with two setae of different sizes on each abdominal segment and on metathorax, longer seta 34–42 (30–41) µm long, and shorter seta about 23 (18–22) µm long.

Ventral surface: with numerous long, narrow flagellate setae of varying lengths, each 38–72 (36–96) µm long, present on abdominal segments and on medial area of thorax; largest setae located on cephalic region. Enlarged conical setae absent. Suranal setae flagellate, each 48–60 (46–50) µm long. Macrotubular ducts symmetrical, narrow and very long, each about 29 (24) µm long and 5 (5) µm wide, scattered over entire surface; ducts on abdominal segments narrower. Microtubular ducts absent. Quinquelocular pores, each about 5 (5) µm diameter, present close to spiracles and sparse across all abdominal segments. Trilocular pores restricted to near spiracles. Cruciform pores sparse, present marginally in cephalic and thoracic regions. Spiracles each about 60 (46) µm long, 28 (14) µm wide. Legs well developed, large in relation to body size; claws each with a denticle; claw and tarsal digitules of equal size, narrow and with slightly expanded apices. Prothoracic legs: coxae each about 113 (120) µm long; trochanter + femur each about 180 (168) µm; tibia each about 91 (91) µm, with 5 setae; tarsi each about 108 (106) µm; claw about 29 (29) long. Mesothoracic legs: coxae each about 120 (120) µm long, with microspinules; trochanter + femur about 180 (187) µm long; tibia about 120 (120) µm long; tarsi each about 132 (120) µm; claw about 38 (38) µm long. Metathoracic legs: coxae each about 136 (127) µm long, with microspinules and with about 50 irregularly-shaped pores; trochanter + femur about 191 (186) µm; femur with 5 setae and 10–12 marginal pores; tibia about 132 (98) µm long with 4 setae; tarsi each about 140 (108) µm; claw about 24 (24) µm long. Antennae each about 196 (166) µm long, with 7 segments, third segment longest, about 48 (48) µm long, without setae. Frontal lobes absent. Labium 3 segmented, basal segment with 2 pairs of setae. Anal tube sclerotized.

Distribution. Argentina, Neotropical region; Chaco subregion; Chaco province.

Comments. The adult female of A. haywardi Juarez & González sp. nov. resembles that of A. dubius (Cockerell), but differs in that the latter species has (character-states for A. haywardi in brackets): (i) five setae on the metathoracic tibiae (four); (ii) six setae on the prothoracic tibiae (five); (iii) dorsal setae arranged in longitudinal bands (in lines parallel to intersegmental lines); (iv) one type of microtubular ducts (two types); (v) several cruciform pores on the abdomen (absent); (vi) ventral conical setae present (absent), and (vii) that it lacks a sclerotized anal tube (anal tube present). Although A. dubius, which has been recently found in Brasil on Calliandra sp. and in Venezuela on Prosopis sp. (Foldi & Kozár 2007), is a highly variable species, the above combination of character-states is considered to be sufficient to separate the two species.

Etymology. The name of the species is dedicated to Kenneth Hayward, British entomologist, who worked in Argentina in the 20th century and is internationally recognized for his contribution to agricultural entomology.