A second species of Etiennea (Coccidae: Coccoidea: Sternorrhyncha) from the New World

Chris Hodgson^1,a and Takumasa Kondo^2,b

¹ Department of Biodiversity and Biological Systematics, The National Museum of Wales, Cardiff, CF10 3NP, Wales.
² Department of Entomology, University of California, 1 Shields Avenue, Davis, California 65616, USA

Etiennea Matile-Fererro 1984: 100.

Etiennea burseraHodgson & Kondo sp. nov. (Figure 1)

Material examined

HOLOTYPE : MEXICO, intercepted in USA, on Bursera sp., 3.ii.2005, B. Abijoy (USNM): 1/1 adult ♀, young and in good condition.

PARATYPES: data as for holotype (USNM): 4/4 adult ♀♀, in good condition but 1 partially sclerotised and other 3 heavily sclerotised.

Described mainly from holotype specimen, with some details checked on 2 other specimens, these indicated below by ranges of data.

Unmounted material

Not seen.

Mounted material

Length 1.9–2.5 mm, width 1.5–2.5 mm. Body oval, longer than wide when young, becoming wider than long when old. Derm thick, with a small area of areolated sclerotisation around anal plates and dorsal to mouthparts on young specimens, becoming densely sclerotised throughout on old material, with abundant, dense, cell-like areolations, each with a paler pore; anal cleft closely adpressed, about 1/4–1/6th body length. Marginal spines marginal on young specimens, but appearing ventral on older specimens when a pseudomargin developes; stigmatic clefts shallow, each with 3 stigmatic spines. Antennae and legs well developed.

Dorsum

Derm of young specimens membranous, with pale oval areolations, each areolation rather variable in shape but perhaps radiating rather approximately from an area dorsad to mouthparts and from around anal plates; each areolation with a microductule. Derm later becoming heavily sclerotised throughout as described above. Dorsal setae each spinose, those medially longer (15–18 μm) than most lateral setae (11–13 μm), each with a heavily sclerotised basal-socket; present fairly randomly throughout dorsum, including sclerotised areas; perhaps least abundant marginally. Dorsal microductules present in each dermal areolation, each round, 2.5–3.0 μm in diameter, with a long inner ductule. Simple pores each about 1 μm in diameter, most abundant submarginally but present very sparsely throughout. Dorsal tubular ducts absent. Preopercular pores each circular and roundly convex, 9–10 μm wide, with a granulate surface; present in a loose, broad group of about 30 in front of anal plates; perhaps restricted to abdomen. Dorsal tubercles each large, round, sclerotised, without satellite tubular ducts in outer sclerotised ring; each tubercle about 18–22 μm in diameter; present in a submarginal ring, with 3–5 per side, mainly on abdomen, none on thorax. Pocket-like sclerotisations present, each about 1/4th width of dorsal tubercles, rather variable in shape; situated between dorsal tubercles in submarginal ring; with 1–5 per side, mainly on abdomen, none on thorax. Anal plates together quadrate, each 170–183 μm long, combined widths 128–145 μm, each plate with outer angle rather rounded and posterior margin slightly longer than anterior margin; each plate with 4 pairs of setae: anterior inner margin setae at about mid-point along inner margin, each about 13 μm long; posterior inner margin seta larger, with a flagellate apex, about 36 μm long; apical and outer margin setae both about 8 μm long, latter near apex. Ano-genital fold with about 5 setae along anterior margin, longest perhaps 33 μm long, and probably with 2 pairs of short setae laterally. Anal ring heavily sclerotised; number of setae present uncertain, probably 8, each about 150 μm long.

Margin

Marginal setae strongly spinose, rather similar to dorsal setae but slightly smaller, each seta 10–18 μm long, up to about 25 μm near anal cleft; anal lobe setae much longer, up to 60 μm long; each with a heavily sclerotised basal-socket; with 15–21 between eyespots, and with (on each side) 8–11 between eyespots and anterior stigmatic clefts; 16–18 between stigmatic clefts and 39–56 between stigmatic clefts and anal clefts. Stigmatic clefts shallow, each with 3 stigmatic spines, median spines each about 75–80 μm long, with a basal socket similar to those of marginal setae; lateral spines each 23–35 μm long, with narrower basal sockets. Eyespots marginal; each 27–28 μm wide.

Venter

Derm entirely membranous. Pregenital disc-pores each mainly with 10 loculi and about 6–7 μm wide; with rather few around genital opening and then apparently absent medially on more anterior abdominal segments, but present as a sparse submedial band laterad to coxae as far forward as anterior spiracles; a few also present medially on thorax. Spiracular disc-pores each with mainly 5 loculi; present in a narrow band between each spiracle and margin, with about 32–48 in each band. Ventral microducts present throughout venter, subequal in size to dorsal microductules. Tubular ducts present, of one type, each with a fairly long outer ductule (14–17 μm long) and a slightly narrower inner ductule (10–11 μm long) with a large terminal gland; present in a fairly wide submarginal band. Ventral setae: with 4 pairs of interantennal setae, longest about 50 μm long; with pairs of long pregenital setae in abdominal segments VI–VIII; submarginal band sparse, with fine, short setae; other setae very sparse, but with a distinct concentration along anterior band of spiracular disc-pores. Spiracles normal but relatively small; width of each peritreme: anterior 40–48 μm, posterior 59–68μm. Legs normal; pro-tibia and tarsus fused on only clear specimen, with a strong indentation on dorsal margin; other tibia and tarsi with a distinct articulation but with no articulatory sclerosis; all segments with few setae; claws without a denticle; with one claw digitule broader than other; tarsal digitules subequal in length to claw digitules; dimensions of metathoracic legs (μm): coxa 132; trochanter + femur 145–178, tibia + tarsus 185–225; claw 27–28. Antennae each with 6 segments; total length 327–356 μm. Clypeolabral shield about 200 μm long.

Comments

The adult female of E. bursera appears to belong to the group of Etiennea species in which the dorsal tubercles lack satellite tubular ducts and which lack tubular ducts elsewhere on the dorsum. It is closest to E. carpenteri (Newstead), E. ferox (Newstead) and possibly E. gouligouli Hodgson in having 6-segmented antennae, but differs from all known species in possessing a sparse submedial band of multilocular disc-pores lying between the area laterad of coxae and the submarginal band of ventral tubular ducts. In the key given in Hodgson (1991), E. bursera keys out to couplet 18, which should therefore be modified as follows:

18.	Antennae 6 segmented; multilocular disc-pores rare or absent on anterior abdominal segments, but present as a sparse band laterad to coxae as far forward as anterior spiracles.	E. bursera sp. nov.
-	Antennae 8 segmented; multilocular disc-pores frequent on anterior abdominal segments, but not present submedially laterad to coxae between pro- and mesocoxae	19
19.	Preopercular pores generally less than 70 and never extending onto head; antennae more than 400 μm long; lateral stigmatic spines distinctly shorter than marginal spines.	E. ferina
-	Preopercular pores extending onto head region and generally more than 100; antennae less that 300 μm long; lateral stigmatic spines subequal in length to marginal spines.	E. capensis

Geographical distribution

Seventeen out of the nineteen known species of Etiennea occur on the African continent, the exceptions being two New World species: E. montrichardiae (Newstead) from Guyana, and the new species described above from Mexico, E. bursera. Only two non-cosmopolitan genera of Coccidae are currently believed to be restricted to Africa and South or Central America, Alecanochiton Hempel (including Avricus De Lotto, see Hodgson 1994) and Etiennea. Species in two other non-cosmopolitan, mainly neotropical genera: Akermes Cockerell and Toumeyella Cockerell, have been recorded from both Africa and the New World in the past. However, Akermes colae Green and Laing was recently placed in Pseudocribrolecanium Kondo (Kondo 2006), a genus currently restricted to Africa, and Toumeyella lomagundiae Hall and T. obunca De Lotto, both only known from southern Africa, have recently been transferred to a new genus (Kondo 2007). Several other genera are also known from both Africa and South or Central America: Ceroplastes Gray, Coccus L., Inglisia Maskell, Kilifia De Lotto, Milviscutulus Williams and Watson, Parasaissetia Takahashi, Parthenolecanium Sulc, Protopulvinaria Cockerell, Pulvinaria Targioni Tozzetti, and Vinsonia Signoret. However, as currently understood, these genera are cosmopolitan, although Ceroplastes, Coccus, Pulvinaria and Saissetia have many species that are endemic in both the Ethiopian and Neotropical regions. The disjunct distribution of these genera (plus Etiennea and Alecanochiton), suggest a Gondwanan origin, a pattern that has also been observed in many pseudococcids (Williams, 1985) and eriococcids (Hoy, 1962; Miller 1970; Miller and Gonsález, 1975).

Taxonomic remarks

The above description agrees well with the generic diagnosis given in Hodgson (1991), and E. bursera is clearly closely related to most of the species currently included in this genus. It shares many features with E. ferina (De Lotto) and E. capensis Hodgson, i.e. presence of (i) dorsal tubercles without satellite ducts; (ii) pocket-like sclerotizations; (ii) sharply spinose marginal setae; (iii) well-developed stigmatic spines; (iv) normally developed legs; (v) multilocular disc-pores at least medio-laterally on all abdominal segments and medially on the thorax; and absence of (vi) dorsal tubular ducts, and (vii) ventral tubular ducts medially (Hodgson, 1991). However, E. bursera differs from both E. ferina and E. capensis in having (i) only 6 antennal segments and (ii) in the absence of multilocular disc-pores medially on the venter (the other two species have 8-segmented antennae and multilocular disc-pores present medially on the venter). Two other species of Etiennea are known to have 6-segmented antennae, E. gouligouli Hodgson and E. ferox (Newstead). However, E. bursera differs from these other two species in having well-developed legs (reduced on the other 2 species). In addition E. gouligouli has inverted tubular ducts (absent on E. bursera), while E. ferox has very few ventral submarginal tubular ducts (much more abundant on E. bursera) (Hodgson, 1991).

Although E. bursera is clearly closely related to many species currently included in the genus Etiennea, it is not certain whether they are all congeneric with the type, E. villiersi. In a study of the 1^st-instar nymphs, Kondo and Williams (2005) concluded that E. villiersi was close to Hemilecanium imbricans (Green), H. mangiferae Kondo and Williams and H. theobromae Newstead, as the crawlers of these four taxa share a range of features, particularly 2 pairs of cribriform plates. The 1st-instar nymphs of the other Etiennea species lack most of these characters (Hodgson, 1993) - in particular the 2 pairs of cribriform plates typical of the above four species - suggesting that all but the type species might be better placed in a new genus, leaving Etiennea either as a monotypic genus, or as a junior synonym of Hemilecanium. However, no action is being taken here.

Acknowledgements

Many thanks to Greg Evans (USDA/APHIS, Beltsville) and to Bertram A. Lindsey (USDA/APHIS/CA) for kindly sending specimens of this interesting species for study. CJH also thanks The National Museum of Wales for providing research facilities.