Dactylopius O.G. Costa, 1835

Hodgson, Chris, 2020, A review of neococcid scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) based on the morphology of the adult males, Zootaxa 4765 (1), pp. 1-264 : 67-68

Dactylopius O.G. Costa, 1835 .

Diaprosteci Costa 1828a, 7. Unavailable name.

Dactylopius Costa 1829, 16 . Type species: Dactylopius coccus Costa by subsequent designation ICZN 1983, 77.

Introduction. This family, as currently understood, contains only the genus Dactylopius Costa with 11 species ( García Morales et al. 2019). The adult males of three species have been described previously, D. confusus (Cockerell) and Dactylopius sp. nr. confusus (Cockerell) by Loubser (1966), and D. coccus Costa by Pérez Guerra and Kosztarab (1992). According to Pérez Guerra and Kosztarab (1992), the material collected and described by Loubser (1966) as D. sp. nr. confusus from Hermon, Cape Province, South Africa, is referable to Dactylopius austrinus De Lotto (1974) . The description of D. coccus by Pérez Guerra and Kosztarab (1992) is poor and so D. coccus is redescribed below.

The molecular studies of Cook and Gullan (2004) and Gullan and Cook (2007) have all placed the genus Dactylopius sister to the Acanthococcid eriococcid clade, whereas the cladistic study based on the adult male morphology ( Hodgson & Hardy 2013) found the Dactylopiidae to be sister to the Gondwanan clade. However, D. coccus (redescribed below) has the trochanter sensilla in a triangle on each side whereas they are arranged in a more or less a straight line on all genera in the Gondwanan clade; this is here considered to be a highly significant feature, suggesting that Dactylopius is closer to the Acanthococcid clade. However, unlike the adult males in the Acanthococcid clade, those of D. coccus share the following character-states with Eriococcus buxi in the BSE clade (condition in Acanthococcid clade in brackets): (i) alary setae absent (present), and (ii) postmesospiracular setae present (absent). On the other hand, unlike male E. buxi , adult male Dactylopius sp. have the following character-states: (i) absence of hamulohalteres (present), (ii) no postoccipital ridge (present), and (iii) capitate setae on several antennal segments (apical segment only). Despite these differences, it is clear that Dactylopius falls within the overall umbrella term “ Eriococcidae ”. Because of the distribution of the trochanter sensilla, the Dactylopiidae are here discussed prior to the Gondwanan clade species.

Based on the detailed description of D. coccus below and on the descriptions of D. confusus and Dactylopius sp. near confusus ( D. austrinus ) given by Loubser (1966), it would appear that the Dactylopiidae can be diagnosed on the following adult male characters.

Family diagnosis of Dactylopiidae based on adult male morphology. Body quite large, not attenuated; with few setae, all hs; loculate pores absent apart from in glandular pouches. Head: Median crest distinct and long, extending posteriorly to well past posterior margin of ocular sclerite; without striations or reticulations; postoccipital ridge absent; pores absent; genal setae present; dorsal simple eyes subequal to or slightly larger than ventral eyes, latter quite far forward; ocelli placed close to postocular ridge; ocular sclerite without any setae and striations or reticulations; preocular ridge short both dorsally and ventrally; interocular ridge present; antennae 10-segmented, each flagellar segment rather club-shaped; fs all short and fat; flagellar segments each with many fs, a few hs and with 1–5 capitate setae. Thorax: prosternal median ridge absent; prothoracic setae absent; prescutum oval, with prescutal setae; scutal setae few medially; without a distinct sclerotised invagination on anterior margin near prealare; scutellum rectangular, without a foramen; scutellar setae present; postmesospiracular setae present; basisternum without basisternal setae; metaprecoxal ridge absent; alar lobe absent; alar setae present or absent; sensoria absent; hamulohalteres absent; each trochanter with 3 circular sensoria arranged in a triangle medially; each tibia with 2 apical spurs; most setae on tibia and tarsi spur-like; tarsi two segmented; claws long and thin, almost straight, without a denticle; claw digitules with small capitate apices. Abdomen: tergites and sternites mainly unsclerotised; caudal extensions absent; ostioles absent; glandular pouches present; glandular pouch setae extremely short; abdominal segment IX large, lying under segment VIII, but fused to style; anal opening large; style narrowly triangular and blunt; style with a group of setae dorsally.

Note. Loubser (1966) shows 2 alar setae on the wings of both D. confusus and D. austrinus ; they are not shown on the illustration of D. coccus by Pérez Guerra and Kosztarab (1992). In the present study, no alar setae could be detected on the males of D. coccus descibed below, nor on those of D. indicus Green (= ceylonicus (Green)) and D. confusus (Cockerell) . However, 3 were present on each wing of D. tomentosus from California (Southern California, on Opuntia echinocarpa (Cactaceae) , 1.x.1924, A.P. Dodd (USNM)) and so it would appear that this character is variable.

Comment. Adult male Dactylopius species differ from those in the acanthococcine-group as follows: (i) postoccipital ridge absent; (ii) setae on ocular sclerite absent; (iii) interocular ridges present; (iv) prosternal median ridge absent; (v) postmesospiracular setae present; (vi) alar lobes absent; (vii) hamulohalteres absent, and (viii) presence of very short glandular pouch setae. Adult male Dactylopius species differ from those in the Gondwanan-group as follows: (i) abdomen not attenuated; (ii) postoccipital ridge absent; (iii) interocular ridge present; (iv) antenna with short, plump fleshy setae, and (v) the sensoria on each side of each trochanter oval, more or less in a triangle.