Rastrococcus namartini, Williams, D. J. & Henderson, R. C., 2005

Williams, D. J. & Henderson, R. C., 2005, A new species of the mealybug genus Rastrococcus Ferris (Hemiptera: Sternorrhyncha: Pseudococcidae) from New Zealand, Zootaxa 1085, pp. 47-60 : 49-58

Rastrococcus namartini sp. nov.

Adult female ( Figs. 1 , 6 )

Description

Appearance in life: covered in white flocculent wax, noticeably in bands across body; with 7 long wax filaments extending from each side of abdomen, two shorter and thicker wax filaments close together each side of mid­thorax and a pair of thick wax filaments extending forwards from anterior margin of head. Forelegs and antennae, visible in gap between thoracic and head filaments, appear translucent white, with antennae held pointing slightly back towards thoracic margin and legs positioned forwards. Other legs not generally visible from above. Body of adult female on microscope slide, membranous, oval, widest at about abdominal segments II or III; 1.30–1.90 mm long, 0.65–1.00 mm wide. Anal lobes moderately developed, each ventral surface with an apical seta 140­170 µm long. Antennae long for size of body, slender, each 720–860 µm long, with 9 segments. Legs well developed, long and slender; hind trochanter + femur 400–480 µm long, hind tibia + tarsus 450–550 µm long; claw slender, 42–55 µm long, without a denticle, digitules knobbed, longer than claw. Tarsal digitules flagellate. Ratio of lengths of hind tibia + tarsus to hind trochanter + femur 1.02–1.32. Ratio of lengths of hind tibia to tarsus 2.46–3.15. Translucent pores few, present on posterior surface of each hind tibia and some either present or absent at distal end of each hind femur. Labium wider than long, about 70 µm long, 100 µm wide, noticeably shorter than clypeolabral shield. Circulus absent. Ostioles represented by poorly­developed posterior pair only. Anal ring longer than wide, 70–90 µm long, 65–70 µm wide, often situated a short distance from apex of abdomen, with 2 rows of cells and 6 setae (each about 85­105 µm long). Cerarii numbering 10 distinct pairs, represented by C1, C8, C9 and C12–18. Anal lobe cerarii each smaller than anal ring, with about 10 slender truncate­conical setae of different sizes, usually 2 larger than others, largest each about 12.5 µm long, 7.5 µm wide at base, tapering to narrow distal end, accompanied by a few minute discoidal pores and a compact group of trilocular pores, each mostly with 3 distorted loculi, 5 subequal sides and obscure centre. Anterior cerarii similar but with fewer setae except frontal pair (C1), each with 17 or 18 truncate­conical setae, of different sizes, largest each about 12.5 µm long, 10 µm wide at base. Area surrounding setal bases of each cerarius lightly sclerotized. Positions of at least 4 cerarii between some main cerarii on head, thorax and abdominal segment I with small concentrations of trilocular pores and 2 or 3 widely­separated pointed setae on membranous areas.

Dorsal surface with short, stiff pointed setae, 6.2–7.5 µm long, some scarcely longer than diameter of setal collars, widely separated, all more slender than pointed setae in positions of absent cerarii. Multilocular disc pores absent. Trilocular pores, similar to those in cerarii but slightly smaller, evenly distributed and widely separated. Discoidal pores scarce, minute, each smaller than a single loculus of a trilocular pore.

Ventral surface with mostly short flagellate setae; cisanal and obanal setae each 25­35 µm long; single marginal setae on each of abdominal segments II–VII about 65 µm long; similar long setae present in area between antennae and anterior edge of clypeolabral shield. Multilocular disc pores in an unusual distribution, present submarginally on abdominal segments III or IV–VII, numbering 5–32 altogether in available specimens, larger numbers usually on anterior segments; each pore about 7.5 µm in diameter, with 10 loculi. Quinquelocular pores, each about 5 µm in diameter, evenly distributed over surface. Trilocular pores of larger type, sometimes present around margins in small numbers. Discoidal pores, same as on dorsum, sparse. Oral collar tubular ducts absent.

First instar ( Fig. 2 )

Body on microscope slide, oval, membranous, about 0.51 mm long, 0.25 mm wide; widest at about abdominal segment II. Anal lobes placed fairly wide apart, poorly developed, each ventral surface with an apical seta about 250 µm long. Antennae 195–215 µm long, with 6 segments. Legs well developed; hind trochanter + femur about 100 µm long, hind tibia + tarsus 112–115 µm long; claw slender, about 25 µm long. Ratio of lengths of hind tibia + tarsus to hind trochanter + femur 1.12–1.15. Ratio of lengths of hind tibia to tarsus 0.70–0.84. Distal trochanteral setae conspicuous, each about 70 µm long. Labium widely triangular, about 35 µm long, 60 µm wide, much shorter than clypeolabral shield. Circulus absent. Anal ring situated at apex of abdomen, 30–35 µm long, 30 µm wide, with 2 rows of cells and 6 setae, each about 50 µm long. Ostioles represented by poorly­developed posterior pair only. Cerarii numbering 16 pairs. Anal lobe cerarii each with 2 bluntlypointed conical setae, each about 7.5 µm long, with prominent collar, accompanied by a single distorted trilocular pore. Anterior cerarii similar, present on all abdominal segments, meso­ and metathorax, and on head (C1); some cerarii lacking on head and thorax; each cerarius with 2 short conical setae, each about 5 µm long, with thick wide collar, associated with a single distorted trilocular pore; occasionally only a single seta present in a cerarius.

Dorsal surface with minute slender setae, about 4 situated across most abdominal segments and appearing as longitudinal submarginal and submedial rows; becoming more scattered on head and thorax. Trilocular pores, similar to those in cerarii, sparse, present in medial areas of head and thorax.

Ventral surface with slender setae, longer than those on dorsum; marginal setae on abdomen longer, each about 25 µm long. Quinquelocular pores, few, situated on head, thorax and medially on abdominal segments VI and VII. Discoidal pores minute, represented by 1 or 2 on margins of posterior abdominal segments.

Second­instar male ( Fig. 3 )

Body on microscope slide, ovoid, 0.65 mm long, 0.36 mm wide, widest at about prothorax. Anal lobes poorly developed, each ventral surface with an apical seta about 95 µm long.

Antennae each about 310 µm long, with 6 segments. Legs well developed, hind trochanter + femur 160 µm long, hind tibia + tarsus 180 µm long; claw slender, about 40 µm long. Ratio of lengths of hind tibia + tarsus to hind trochanter + femur 1.13. Ratio of lengths of hind tibia to tarsus about equal. Labium widely triangular in shape, about 50 µm long, 75 µm wide. Anal ring about 45 µm in diameter, bearing 6 setae, each about 55 µm long. Ostioles represented by posterior pair only, poorly developed, without setae or trilocular pores. Cerarii numbering 10 distinct pairs, represented by C1 and C10–18. Anal lobe cerarii each with 3 conical setae, each about 7.5 µm long, pointed or apically blunt, accompanied by 2 or 3 distorted trilocular pores. Anterior cerarii on abdomen similar, each sometimes with 3 or 4 trilocular pores. Positions of remaining cerarii on head and thorax with scattered, short pointed setae and trilocular pores.

Dorsal surface with short slender setae. Trilocular pores distorted, similar to those in cerarii, distributed mostly across middle of segments. Oral collar tubular ducts present, each about 10 µm long, slender, scarcely wider than a single loculus of a trilocular pore, mingled with trilocular pores across middle of segments.

Ventral surface with slender setae. Quinquelocular pores present, scattered. Oral collar tubular ducts, same as on dorsum, scattered on head, pro­ and mesothorax, some also present on margins of metathorax and abdomen, except for occasional ducts present medially on abdomen.

Third­instar male (Prepupa) ( Fig. 4 )

Body on microscope slide, membranous, oval, about 1.15 mm long, 0.50 mm wide. Posterior end of abdomen rounded. Anal lobes and lateral margins of abdominal segment VII pointed. Antennae moderately sclerotized, with 9 segments but segments sometimes not clearly defined; last segment tapering to blunt apex. Legs also moderately sclerotized; tibia and tarsus divided; claw short, curved and pointed, with paired digitules about same length as claw. Remains of clypeolabral shield weakly sclerotized. First wing buds lightly sclerotized, 180–200 µm long. Halteres weakly sclerotized. Posterior ostioles present, barely perceptible.

Dorsum with short, slender pointed setae, present across middle of segments. Lateral margins of abdomen and head with cerarii. Anal lobe cerarii each with 3 setae, slightly enlarged, thicker than dorsal setae; other cerarii on abdomen each with 1 or 2 similar setae. Frontal cerarii each with 3 short conical setae, each scarcely longer than setal collars. Multilocular disc pores, each with 10 loculi, similar to those in adult female, fairly numerous and scattered on head and thorax; distributed across middle of abdominal segments. Oral collar tubular ducts, each about same length as a multilocular disc pore and about 2 µm wide, few, present across middle of abdominal segments only. Discoidal pores minute, sparse.

Ventral surface with multilocular disc pores scattered on head and thorax and present in small numbers laterally on most abdominal segments, not so numerous as on dorsum. Discoidal pores represented by 1 or 2 on margins only. Oral collar tubular ducts absent.

Fourth­instar male (Pupa) ( Fig. 5 )

Body elongate, about 1.12–1.36 mm long, 0.55–0.65 mm wide, membranous. Lateral margins of abdominal segments VII and anal lobes (VIII) pointed and sclerotized dorsally, spur­like. Penial sheath membranous, wider than long, with dorsal anal opening near base. Antennae longer than in prepupae, moderately sclerotized, each with 9 segments. Legs well developed, each claw curved and pointed with paired digitules. Head showing signs of postocular ridges. Ostioles present as posterior pair only, represented by mere slits. First wing buds lightly sclerotized, 400–460 µm long. Halteres lightly sclerotized. Remains of clypeolabral shield present but structures obscure.

Dorsal surface with short, slender pointed setae. Cerarii represented by groups of 2 or 3 slender, pointed conical setae on abdomen and by frontal pair each with 4 such conical setae. Discoidal pores minute, a few distributed across middle of abdominal segments and 1 or 2 present on thorax.

Ventral surface with similar slender setae to those on dorsum. Multilocular disc pores present, each with 8 loculi, smaller than those in prepupae, present in small lateral groups on abdominal segments II–VI and 1 or 2 situated near spiracles. Discoidal pores minute, sparse, occurring next to multilocular disc pores only.

Material examined

HOLOTYPE adult female, New Zealand, AK, Hunua Ranges, Massey Track, 6.ii.2005, G.L. & R.C. Henderson, on Myrsine australis (Myrsinaceae) , ( NZAC #05­ 025c).

PARATYPES, same data as holotype, #05­025a, b, e, g, #05­026c, d, e, 1 adult female, 2 first instars + 5 moults, 1 second­instar female + 1 moult, 1 third­instar female, 1 secondinstar male, 2 fourth­instar males (pupae) ( NZAC), 1 adult female ( BMNH); same data but 1.i.2005 (N.A. Martin), #05­017a, f­i, k, 3 adult females, 1 third­instar female (enclosing pharate adult female), 1 second­instar male, 1 third­instar male (prepupa), 2 fourth­instar males (pupae) ( NZAC), 1 adult female ( USNM).

Other Material (all NZAC): WO, Ngatea, 7.xi.1933, Myrsine australis (as Suttonia australis ), R.P.G., (G. Brittin collection No. 237) (misidentified as R. asteliae ), 1 female. AK, Hatfields Beach, Nth end headland, 28.ix.2002, R.C. Henderson, Myrsine australis , #02­214a­b, 1 female, 1 second­instar male. AK, Hunua Ranges, Massey track, 1.i.2005, N.A. Martin #05­017b­e, j, l­m, 3 adult females, 4 third­instar females, 3 second­instar females, 1 second­instar male; same data but 6.ii.2005, G.L. & R.C. Henderson, #05­025d, f + #05­026a­b, 2 adult females, 6 second­instar females, 3 third­instar females, 1 parasitised prepupa, 3 parasitised second­instar males. AK, Whitford, Claude Stream Valley, 21.v.2005, R.C. Henderson, Myrsine australis , #05­175a–d, 3 adult females, 1 second­instar female, 10 first instars.

Comments

The adult female of this species is unusual in possessing only 10 pairs of distinct cerarii. The positions of some of the other cerarii are occupied by a few scattered trilocular pores and pointed setae that are only a little wider than the main dorsal setae. Furthermore, the multilocular disc pores are much reduced in number from 5–32 only, occurring on the submargins of the abdomen, and the trilocular pores have a distorted appearance, each often appearing with 5 subequal sides and with an obscure centre. A circulus is absent.

R. asteliae differs from R. namartini in possessing a circulus and 16 pairs of cerarii. Moreover, the multilocular disc pores in R. asteliae are numerous and are present in wide bands on the abdomen although they are absent from most of the medial areas. R. namartini seems to be more similar to R. matileae Williams & Watson , described from New Caledonia, a species possessing 14 pairs of cerarii and with reduced numbers of submarginal multilocular disc pores on the abdomen, although noticeably more numerous than in R. namartini . The new species is also similar to R. matileae in lacking a circulus. R. namartini seems to belong to a group of Rastrococcus species on the eastern fringe of the present distribution and it is likely that further species will be found in New Caledonia and New Zealand.

Nanda & Ghose (1989) and Pramanik & Ghose (1991) have reported that secondinstar males of R. iceryoides in India do not produce cocoons but a fluffy cocoon is produced by the second­instar male of N. namartini .

Figures

FIGURE 1. Rastrococcus namartini sp. nov. Adult female. Specimen from New Zealand, Hunua Ranges, on Myrsine australis, 6. ii. 2005, G. L. & R. C. Henderson.

FIGURE 2. Rastrococcus namartini sp. nov. First instar. Specimen from New Zealand, Hunua Ranges, on Myrsine australis, 6. ii. 2005, G. L. & R. C. Henderson.

FIGURE 3. Rastrococcus namartini sp. nov. Second­instar male. Specimen from New Zealand, Hunua Ranges, on Myrsine australis, 6. ii. 2005, G. L. & R. C. Henderson.

FIGURE 4. Rastrococcus namartini sp. nov. Third­instar male (prepupa). Specimen from New Zealand, Hunua Ranges, on Myrsine australis, 6. ii. 2005, G. L. & R. C. Henderson.

FIGURE 5. Rastrococcus namartini sp. nov. Fourth­instar male (pupa). Specimen from New Zealand, Hunua Ranges, on Mysine australis, 1. i. 2005, N. A. Martin.

FIGURE 6. Rastrococcus namartini sp, nov. Adult female, external appearance.