Apiomorpha nookara Mills, MacDonald, Rigby & Cook

Mills, Penelope J., Macdonald, Melanie L., Rigby, Lisa M. & Cook, Lyn G., 2011, A recently discovered species of Apiomorpha Rübsaamen (Hemiptera: Coccoidea: Eriococcidae) with unusual gall morphology, Zootaxa 3093, pp. 55-63 : 57-62

Apiomorpha nookara Mills, MacDonald, Rigby & Cook sp. n.

Holotype female, ex. Eucalyptus racemosa , Australia, New South Wales, Arakoon Road, Arakoon, S30°53’ 29.6, E153°04’06.1”, 26.xii.2008, L. G. Cook, code LGC01098. To be deposited in the Australian National Insect Collection, Canberra along with its associated gall. Additional material of the holotype specimen (LGC01098) includes gut and ovary tissue stored at -70°C in the School of Biological Sciences at The University of Queensland ( Australia) and genomic DNA stored at -20°C at the same institution (both labeled LGC01098); holotype material also includes DNA sequence data: partial 18S SSU rDNA (Genbank accession: JN863287 ), partial 28S LSU rDNA (Genbank accession: JN863288 ) and partial COI (Genbank accession: JN863289 ).

Paratypes: 2 slide-mounted females from collection LGC00343 (labeled f1 and f2), ex. E. racemosa , Australia, New South Wales, near South West Rocks, S30°53’25”, E153°04’16”, 22.v.2005, L. G. Cook. 1 slide-mounted female from collection LGC00820, ex. E. racemosa , Australia, New South Wales, corner of Bruce Field Street and Keith Andrews Avenue, South West Rocks, S30°54’05.5”, E153°02’10.7”, 31.xii.2007, L. G. Cook.

Adult female ( Fig. 1 ). Description based on four whole adult females (slide mounted material: LGC00343f1, LGC00343f2, LGC00820, LGC01098) and one partial female (slide-mounted: LGC00309).

Body. 5–8 mm long, 3–5 mm wide. Abdomen tapered to anal lobes. Integument mostly membranous in young adult females but moderately to heavily sclerotised in older specimens. Abdominal segment VIII longer ventrally than dorsally.

Antenna. 5 segmented, but segmentation often indistinct, 140–170 μm long; with 2–4 pegs (fleshy setae) (18– 45 μm long) and 1 coeloconic peg (10 μm long) on apical segment; 5–7 trichoid setae (10–46 μm long) present on other segments as follows: I 4–5 (mostly 4), II 0, III 0–3 (mostly 1), IV 0–1 (mostly 1).

Labium. 121–140 μm long, 111–130 μm wide.

Clypeolabral shield. 157–210 μm long, 125–150 μm wide.

Spiracles. Typical trilabiate type, as per A. minor species group of Gullan (1984). Mesothoracic spiracles 200– 277 μm long, 106–142 μm wide, metathoracic spiracles 200–300 μm long, 120–173 μm wide.

Legs. Sparse trichoid setae scattered on all segments. Forelegs shortest (344–493 μm), mid legs (571–730 μm) shorter than hind legs (875–951 μm). Hind coxa and hind femur with high density of pustules, evenly spread across dorsal and ventral surfaces. Claw distinct on all legs in young adult females, indistinct in older females.

Anal ring. Invaginated (although not clear on all specimens), 105–161 μm in diameter, slightly concealed by a sclerotised shield, with 16–20 ring setae, each 105–320 μm long.

Anal lobes. Lightly to moderately sclerotised, 380–480 μm long. Tapering apically and apices slightly divergent. Each apex distinctly bifurcate, with terminating subequal spine-like processes 10–25 μm long, lying in the dorso-ventral plane. Trichoid setae 90–350 μm long, mostly restricted to the ventral and outer surfaces of lobes, with 1 long (340 μm) robust trichoid seta (most broken on specimens examined) originating ventrally from near apex of anal lobes.

Venter. Multilocular disc pores (with 5–11 loculi, but predominantly 7 and 9); clustered around mouth, but sparsely distributed from head (H) to AVII inclusive; no pores present on AVIII. Trichoid setae (16–353 μm long) densest and most robust on AVIII and anal lobes; setae become sparser anteriorly.

Vulva. Intersegmental between AVI and AVII.

Dorsum. Spine-like setae in irregular rows as follows: H–TI and TII (0), TIII (2 or 3), AI (1–4), AII (4–6), AIII (3–9), AIV (3–15), AV (6–12), AVI (6–15), AVII (7–11). Multilocular disc pores (5–11 loculi, predominantly 7 and 9) sparse, mostly in a band towards the anterior margin on segments TII–AVI, although several can be found posteriorly, scattered on AVII. No multilocular disc pores on AVIII.

Gall of adult female ( Figs 2–4 ). Description based on 15 galls of adult females, including collections LGC01098, LGC00343, LGC00820, LGC00309, LGC00305 and LGC00716. Host, localities and number of adult female galls measured for each code can be found in Table 1.

LGC00309 E. racemosa S30°54’10” E153°02’07” 1 1

LGC00343 E. racemosa S30°53’25” E153°04’16” 2 2

LGC00716 E. racemosa S30°53’25” E153°04’16” 0 1

LGC00820 E. racemosa S30°53’19” E153°04’23” 1 9

LGC01098 E. racemosa S30°53’30” E153°04’06” 1 1

Gall ovoid to ovo-cylindrical ( Fig. 2–4 ), 9.1–14.5 mm long, 6.1–8.5 mm wide, attached to plant stem at gall base. Young galls red or green, turning brown or grey when older. Apex of gall blunt, 2.0– 6.5 mm in diameter. Outer opening of gall irregular, 1–4 mm wide. Outer chamber 1.0–5.0 mm in diameter and 1.0–4.0 mm deep. Apical orifice of inner chamber (in which female resides) circular: 0.4–1.5 mm in diameter. Inner chamber similar in shape to that of adult female: 5.2–8.7 mm long and 3.1–5.0 mm in diameter.

Gall of adult male ( Fig. 5). Only a single gall of an adult male has been found (collection LGC00343). It is small and tubular, 6 mm long, 2 mm wide, flared at the apical opening and was found on a leaf. Six galls of immature males were also collected from leaves of the same plant.

Phylogenetic relationships ( Fig. 6 ). Analysis of the mtDNA COII region ( Fig. 6 ) suggests that A. nookara is closely related to A. minor . Although there is little support for most relationships within Apiomorpha using this gene region ( Fig. 6 ), there was strong bootstrap support for a sister relationship between A. minor (2n=84 form) and A. nookara (BS= 99 in MP, 82 in ML). Apiomorpha nookara is also morphologically similar to members of the A. minor species group ( A. minor , A. sessilis and A. annulata ), and using Gullan's (1984) key to adult females for A. nookara leads to the final couplet separating A. sessilis and A. annulata . Given the phylogenetic results and the morphological similarity, we place A. nookara in the A. minor species group.

Karyotype ( Figs 7–10 ). Both individuals karyotyped (LGC00309 and LGC01098), and their embryos, had a diploid chromosome number of 2n=6. This karyotype has not been previously reported for specimens from the A. minor species-group, which have counts ranging between 2n=4 to 2n=84 ( Cook 2000; Mills & Cook 2010).

Diagnosis. The biological species concept ( Mayr 1942) was used to delimit A. nookara , with morphological and karyotypic characters assessed to determine whether there is likely reproductive isolation between this population and other populations or species of Apiomorpha . The two-chambered gall of the adult female of A. nookara clearly distinguishes the species from all other described species of Apiomorpha . Only one other described species ( A. variabilis ) has two cavities within the gall, but the galls of adult females of A. variabilis are much larger (23–50 mm long, 21–34 mm wide) than the small galls induced by females of A. nookara (9–14.5 mm long). Furthermore, the galls of A. nookara are ovoid to ovo-cylindrical rather than pyriform like those of A. variabilis . The adult female of A. variabilis is also different from A. nookara . Most strikingly, A. variabilis has many more spine-like setae than A. nookara on abdominal segments AIII-AV. Apiomorpha variabilis : 14–32 (AIII), 17–27 (AIV), 15–24 (AV). Apiomorpha nookara : 3–9 (AIII), 3–15 (AIV), 6–12 (AV).

The number of spine-like setae on individuals of A. nookara also differs from that of the three species within the A. minor species-group ( A. minor , A. sessilis and A. annulata ) ( Gullan, 1984). Adult females of A. nookara differ from those of A. minor in having no spine-like setae on segment TII, and in having fewer spine-like setae on most of the other dorsal segments. Apiomorpha minor : 4–47 (TIII), 9-59 (AII), 14–58 (AIII), 17–45 (AV), 18–50 (AVI), 12-37 (AVII). Apiomorpha nookara : 2–3 (TIII), 4–6 (AII), 3–9 (AIII), 6–12 (AV), 6–15 (AVI), 7–11 (AVII). Apiomorpha nookara also has multilocular disc pores on the anterior edge of AVII, which are absent on adult females of A. minor .

Adult females of A. nookara differ from adult females of A. sessilis in having no spine-like setae on TII, and having fewer spine-like setae on dorsal segments TIII, AII-AIII, AV and AVII. Apiomorpha sessilis : 6–14 (TIII), 9– 16 (AII), 11–18 (AIII), 14–18 (AV), 13–18 (AVII). Apiomorpha nookara : 2–3 (TIII), 4–6 (AII), 3–9 (AIII), 6–12 (AV), 7–11 (AVII). In addition, the spine-like setae dorsally on AVII in adult female A. nookara are elongated and sharp ( Fig. 11 ), whereas those of A. sessilis are short and blunt ( Fig. 12 ).

Adult females of A. nookara differ from those of A. annulata in having elongated sharp spines dorsally on AVI- AVII ( Fig. 11 ) ( A. annulata has short, blunt spines on these two segments, similar to those found on AVII in adult females of A. sessilis ), and in having fewer spine-like setae on AI and AIII. Apiomorpha annulata : 5–14 (AI), 12– 19 (AIII). Apiomorpha nookara : 1–4 (AI), 3–9 (AIII). Apiomorpha nookara also differs in having multilocular disc pores on the anterior edge of AVII ( A. annulata has none), and antennae that are five-segmented rather than foursegmented in A. annulata (which can be observed more clearly in younger, less-sclerotised adult females).

Host-plant associations and geographic distribution. Apiomorpha nookara has been found only on E. racemosa , the narrow-leaved scribbly gum ( Eucalyptus subgen. Eucalyptus sect. Cineraceae, ser. Psathyroxylon; sensu Brooker 2000). Prior to the synonymies recognised by Pfeil and Henwood (2004), the populations of scribbly gum from which A. nookara has been collected were known as E. signata F. Muell. Eucalyptus racemosa (sensu Pfeil and Henwood 2004) is widespread across New South Wales and Queensland ( Australia), but is confined to woodland or dry sclerophyll forests on sandy and swampy flats ( PlantNET 2011). Given that the host is widespread, it is possible that A. nookara might have a broader distribution than that currently recognised.

Etymology. The species epithet " nookara " is the reverse spelling of the location where the first live specimens were seen—Arakoon Conservation Park near South West Rocks (NSW), and the name of the road along which the holotype specimen (LGC01098) was collected. The name also was chosen because none of the 41 previously described species of Apiomorpha begins with the letter "n". The name should be treated as an indeclinable noun.

Figures

FIGURE 1. Adult female of A. nookara Mills et al. sp. n. The dorsum is shown on the left-hand side, venter on the right. Segments are labelled for the dorsum, with H-TI being the fused head and thoracic segment I, AI is abdominal segment I etc. A representative spine-like seta is shown on the left, and the apices of the anal lobes are shown on the right (dorsal view left, ventral right). Scale bar = 1 mm.

FIGURE 6. Phylogeny of 11 species of Apiomorpha based on a maximum parsimony (MP) analysis of mtDNA sequence data (COII) using an equal-weights scheme. Numbers above branches are bootstrap support values from 100 pseudoreplicates (MP / ML).

FIGURES 2 – 4. Galls of adult females of A. nookara Mills et al. sp. n. 2. LGC 00343; 3. Holotype, LGC 01098, in opened gall; 4. Opened gall of LGC 00820, showing the two chambers. Scale bar = 10 mm.

FIGURES 7 – 10. Mitotic chromosomes from ovaries of A. nookara Mills et al. sp. n. 7 & 8. metaphase cells from specimen LGC 00309; 9. metaphase cell from LGC 01098 (holotype specimen); 10. prophase cell from LGC 01098 (holotype specimen). Scale bars = 10 μm.

FIGURES 11 & 12. Spines on the dorsum of the seventh abdominal segment (AVII) of adult females. 11. A. nookara Mills et al. sp. n.; 12. A. sessilis (Froggatt). Scale bars = 100 μm.