Margarodes

Hodgson, Chris & Foldi, Imre, 2006, A review of the Margarodidae sensu Morrison (Hemiptera: Coccoidea) and some related taxa based on the morphology of adult males, Zootaxa 1263 (1), pp. 1-250 : 1-250

Margarodes ? chukar La Rivers

( Fig. 11 )

Margarodes chukar La Rivers, 1967: 4 .

Material studied

USA, Inyo Co., Paramint Valley , Sand Dunes , 23.viii.1972, Ray Gill ( USNM): 1/ 2ad ♂♂ (in fair condition; although specimens were heavily sclerotised and well developed, the wings appeared to be less well developed and so perhaps had yet to harden properly post­moult) .

Mounted material

Large, 3.3–3.9 mm long, 0.82–0.99 mm wide across prealare. Body moderately setose, setae rather variable in length, with rather parallel­sides and a shallow basal socket, tapering eventually to a fairly sharp point; length 20–100 m (mainly about 45–50 m). Collared setae (cs), bifurcated setae (bs), hairs (hrs), loculate pores (lp) and convex pores (cp) absent. Antennae short, 10­segmented, most segments wider than long with short, parallel­sided setae, some with what might be satellite setae (sats); long setae only frequent on basal 2 segments. Some sclerotised areas with faint nodulations. Legs well developed but all relatively short; anterior legs fossorial; metathoracic leg significantly longest; profemur relatively setose but without bifurcated setae (bs); other legs with distinctly fewer setae; tibial and tarsal spurs absent: tarsi 1 segmented; claws without a denticle, blade like; claw digitules spinose. Abdominal segment I not visible ventrally; with tubular ducts on segments VI and VII; without lateral caudal extensions; abdominal spiracles well developed. Penial sheath strongly sclerotised and appearing rather quadrate, with a short aedeagus.

Head

Triangular to roughly oval in dorsal view, length 330–350 m, width across compound eyes 490– 505 m. Dorsally: dorsomedial part of epicranium (dmep) unsclerotised, with 1 or 2 pairs of medium to long setae. Midcranial ridge (mcr) absent. Postoccipital suture (pos) present as a narrow transverse sclerotisation, with a lightly sclerotised postocciput (poc) posteriorly. Pores absent. Laterally: compound eyes (cde) covering most of head, just or almost touching both dorsally and ventrally; each with about 100 ommatidia, each ommatidium about 25–30 m wide; length of cde 285– 295 m. Each compound eye (cde) with extensions of preocular (procr) and postocular ridges (pocr) around dorsal margin, and also with an extension of preocular ridge (procr) anteriorly and preoral ridge (pror) posteriorly around ventral margin; sclerotised ventral projection (p) absent. Ocular sclerite (ocs) present dorsally posterior to cde, each with a single large ocellus (o) 40–55 m wide. Ventrally: head almost entirely covered by compound eyes, but with a fairly short midcranial ridge (vmcr) extending posteriorly from between antennae where it expands into a heavily­sclerotised, diamond­shaped ventromedial part of epicranium (vmep), with 17–20 long setae on each side. Ventral plate (vp) present medially on posterior margin of head, rectangular and well sclerotised. Cranial apophysis (ca) not detected. Anterior tentorial pits clearly present on either side of mouth (m) near posterior margin of ventral plate. Tentorial arms, tentorial bridge and tendon­like apodemes not detected. Ventral sclerites (vs) absent or fused with cervical sclerite (cv).

Antennae: 10­segmented; rather short, flagellar segments all wider than long; length 685–840 m (ratio of total­body length to antennal length 1:0.21). Scape (scp) 90–125 m long, 100–135 m wide; sclerotised, with 9–17 long setae on dorsal and inner margin + 10 or 11 very short setae, mainly along proximal margin on dorsal surface. Pedicel (pdc) 50–75 m long, 100–110 m wide, articulating with scape; with 16–22 long setae, 3 short setae + 0 (–1?) campaniform sensilla (camp); no basiconic sensilla (bass) present. Remaining segments broader than long: length/breadth in m: III 80–88/95–109; IV 70–100/110–134; V 60–90/100–120; VI 80–85/100–112; VII 72–88/85–95; VIII 75–92/ 76–80; IX 75–84/65–75; X 100–105/60–72. Each segment with a ring of rather short, blunt, parallel­sided setae, each mainly 17–35 m long, a few with a short hair­like setae associated with basal socket of seta (probably satellite setae (sats)); approx. number of setae per segment: III 34–38; IV 47–63; V 39–49; VI 42–45; VII 35–40; VIII 30–32; IX 24–28 and X 37–40; most segments also with 1–8 hair­like setae (hs). Antennal bristles (ab) undifferentiated.

Thorax

Prothorax: separated from head by a broad neck with little indications of a cervical groove. Dorsally: pronotum (prn) unsclerotised. With a pair of large, lightly sclerotised post­tergites (pt), each about as broad as long. Laterally with a pair of strong cervical sclerites (cv) which appear to articulate with ventral end of postocular ridge (pocr), and which broaden close to neck, with a short extension dorsally (possibly ventral sclerite (vs) fused to cv?); with a large pleural apophysis (pla 1); pleural ridge (plr 1) rather short. Ventrally: prosternum (stn 1) unclear but apparently membranous, without a sternite or prosternal apophysis (stn 1 a), but with a lightly sclerotised median ridge. Setae as follows: dorsal: median pronotal setae (mpns) in a distinct group immediately posterior to postoccipital suture; with about 12 long post­tergital setae (pts) just posterior to each posttergite. Laterally with a group of long anterior propleural setae (apl 1 s) on each side of prothorax and an even larger group of posterior propleural setae (ppl 1 s); ventrally with a group of about 8–10 long anteprosternal setae (astn 1 s) postero­laterally to ventral plate; with more than 5 pairs of long prosternal setae (stn 1 s) and with a few antemesospiracular setae (asp 2 s) between anterior spiracle and procoxae.

Mesothorax: dorsally: prescutum (prsc) large and oval, length 320–350 m, greatest width 410–450 m, surface distinctly nodulated; mesoprephragma (phr 1) short; prescutal ridges (pscr) short; prescutal sutures (pscs) forming a distinct groove between prescutum and scutum; prsc without prescutal setae (prscs). Scutum (sct) sclerotised throughout and mostly lightly nodulated, particularly anteriorly; distance between prescutum and scutellum about 230–375 m; with a group of 20–40 scutal setae (scts), each 13–25 m long, on each side of anterior end of scutellum (scl). Scutellum (scl) triangular; without oval membranous areas laterally; with a group of 3–6 small scutellar setae (scls) or minute pores posterolaterally. Mesopostnotum (pn 2) with a large membranous area anteriorly; mesopostnotal apophyses (pn 2 a) large. Laterally: prealare (pra) elongate. Tegula (teg) large and sclerotised, with a group of 20–25 long tegular setae (tegs). Mesopleural ridge (plr 2) well developed, but pleural apophysis (pla 2) not detected. Mesepisternum (eps 2) lightly nodulated. Mesothoracic spiracles (sp 2): width of peritremes 65–75 m, each apparently rather poorly developed and muscle plate rather long and narrow. Ventrally: basisternum (stn 2) nodulated, approximately 570–650 m long, 635–670 m wide; with a total of 30–50 short setae on either side of median ridge (mdr); median ridge (mdr) present but incomplete both anteriorly and posteriorly; basisternum without a marginal ridge (mr) anteriorly but marginal ridge broad, separating basisternum from lateropleurite (lpl); posteriorly with well­developed precoxal ridges (pcr 2); furca (f) rather small, broad basally, lateral arms long, narrow and pointed; lateropleurite (lpl) large and triangular, bounded posteriorly by a broad precoxal ridge and laterally by subepisternal ridge (ser); each lateropleurite (lpl) with a group of 10–18 lateropleurite setae (lpls), each mostly long but with a few of medium­length; also with 1 or 2 small setae on precoxal ridge; subepisternal ridge (ser) distinct posteriorly but fading anteriorly, without setae. Postmesospiracular setae (pm 2 s) absent (or only represented by 0–2 small setae associated with anterior spiracular peritremes). Wing sclerites: apparently similar to other members of this group.

Metathorax: dorsally: metapostnotum (pn 3) with large sclerites which fuse medially; pn 3 not fused to tergites on abdominal segment I; with about 30–40 metatergal setae (mts) medially. Laterally: with a large group of dorsospiracular setae (dss), these about longest setae on body. Suspensorial sclerites (ss) not detected. Pleural ridge (plr 3) well developed; with a shallow pleural apophysis (pla 3) at point where pleural and precoxal ridges (pcr 3) meet, from where a distinct arm extends dorsally from pleural ridge (plr 3) to fuse with metapostnotum. Metepisternum (eps 3) present as a sclerotisation on ventral side of metapleural ridge (plr 3); metepimeron (epm 3) absent. Posterior spiracles (sp 3) similar to those on mesothorax; width of peritremes about 70 m; each with 1 or 2 small setae near rim. Ventrally: with a large group of long antemetaspiracular setae (am 3 s) just ventral to dorsospiracular setae (dss); precoxal ridge (pcr 3) well developed and extending about 350 m medio­ventrally, with a group of long setae along most of precoxal ridge. Postmetaspiracular setae (eps 3 s): 6–10 long setae posterior to precoxal ridge. Metasternum (stn 3) sclerotised, particularly anteriorly, rather quadrate, with long, narrow lateral apophyses (stn 3 a). With a large group of quite long postmesoprecoxal ridge setae (ppcr 2 s); anterior metasternal setae (amss) in a broad group of perhaps 50 quite long setae fusing with postmetaspiracular setae (eps 3 s) laterally; posterior metasternal setae (pmss) with 4–6 quite long setae on either side of stn 3.

Wings: distorted, but appearing to be small and poorly formed; length unknown, width perhaps 950–1000 m. Subcostal thickening (sclt) well developed; wing anterior to subcostal thickening almost unsclerotised; rest of wing membranous, without reticulations; with 15 or 16 circular sensoria (sens) along subcostal thickening but without alar setae (als); radius (rad) and media (med) veins possibly represented by light sclerotisations; alar fold (af) not detected. Alar lobe (al) well developed and lightly sclerotised. Hamulohalteres (h) each mainly membranous, narrow proximally and broadening significantly distally, with a strong vein along anterior margin proximally with distinct indentations on both anterior and posterior margins about 1/3rd along; length 400–425 m, width 350–370 m; with 1 blunt, apically bent, hamulus (ham), about 24–30 m long.

Legs: prothoracic legs fossorial; middle legs noticeably shortest. Prothoracic legs as follows: lengths (m): coxae (cx) 320–330; trochanter (tr) + femur (fm) 545–570; tibia (ti) 145–150; tarsus (ta) + claw (c) 270–275. Coxae (cx) with about 45 very short setae (each 3–7 m long) near coxal base + 9–15 long setae (each 40–50 m) on inner distal surface. Trochanter (tr) with about 20–30 setae but without a long seta on ventral distal margin; each trochanter with about 8–10 campaniform sensilla (camp). Femur (fm) with about 175–200 long setae (each 30–105 m long) + 20–25 short setae (each 8–17 m); bifurcated setae absent (bs). Tibia (ta) with 10–13 long setae + 24–28 short setae; tibio­tarsal segmentation distinct but without articulation. Tarsi (ta) with about 3–10 long setae + 3–9 short setae; tibial (tibs) and tarsal spurs (tabs) absent; with a large group of campaniform sensilla (camp) on proximal dorsal surface. Claws (c) broadly fused to base of tibio­tarsus, with no articulation; without claw digitules (cdgt). Meso­ and metathoracic legs: lengths (m): coxa (cx): II 290–305; III 385–390 m; metacoxa with a group of about 40–55 very short setae near base, and 30–45 long setae distally. Trochanter (tr) + femur (fm): II 455–460; III 505–635 m long; metatrochanter with 23–45 long setae, and with a group of 10 or 11 campaniform sensilla (camp) on each lateral surface near coxal articulation; without a very long seta on ventral distal end; metafemur with 30–53 long + 23–26 short setae. Tibia (ti): II 385–435; III 505–590 m long; metatibia with 12–18 spur­like setae along ventral margin; bifurcated setae (bs) absent; with 67–81 short setae; tibial spurs (tibs) absent. Tarsi (ta) 1 segmented, II 145–160; III 110–135 m long; each with a group of probably at least 5 campaniform sensilla (camp) on proximal dorsal surface; without bifurcated setae (bs) but with 3–6 spur­like setae along ventral surface and 27–30 small setae; without tarsal spurs (tabs); tarsal digitules (tdgt) absent. Claws (c) rather long and blade­like, probably not digitate as on some other Margarodes species ; without a denticle (cd); claw II 146–158 m, III 110–135 m long, with probably 3 or 4 short, blunt, spinelike digitules (cdgt), each about 10–20 m long.

Abdomen

Without caudal extensions. Large tergites (at) and sternites (as) present on all segments (except perhaps tergite VII, which may be absent). Pores entirely absent (apart, perhaps, from near dorsal tubular ducts on segments VI and VII). Dorsal abdominal setae (ads) (of rather variable length, longest about 58–70 m, short setae 8–12 m), distributed as follows: segment I (totals) about 30; II 50–55; III 29–31; IV 29–34; V 18–26; VI 15 or 16; VII 10–13 and VIII 12. Ventral abdominal setae (avs) similar, as follows: II about 11 medially + 7–11 laterally; III 16–26 medially + 3–9 laterally; IV 13–15 medially + 4–9 laterally; V 11–14 medially + 7 or 8 laterally; VI 9 or 10 medially + 4–7 laterally; VII 8–13 medially + 3 or 4 laterally; VIII 21 or 22 medially. Pleurites present on segments II–VIII; pleural setae divided into dorsal (dps) and ventral (vps) groups; with 0–6 dps and 8–23 vps on each segment; pores absent. Segments VI and VII each with a transverse line of large, sclerotised tubular ducts (tdc) dorsally, segment VI with 5–7 and VII with 6, those laterally smaller than those medially; median ducts each about 22 m wide and 53–58 m long, smallest lateral ducts 10 m wide and 35–40 m long; each duct without internal longitudinal ridges but these possibly present on collar. Each group of ducts with a band of minute setae, basal sockets or pores along anterior margin (each socket/pore 4–5 m wide). Abdominal spiracles (asp): 5 pairs, on segments I–V, each oval, strongly sclerotised and obvious; spiracles on segment V appearing to be on a small protuberance, with a strongly sclerotised opening about 80–85 m wide, each inner margin possibly corrugated; openings becoming less distinct anteriorly, so that spiracles on segment I small and relatively unsclerotised; none could be detected on segments VI–VIII, and no trachea visible.

Genital segment: anal opening (a) not detected. Penial sheath (ps) strongly sclerotised, appearing approximately quadrate with rather parallel sides, but narrowing abruptly to a bifurcate blunt apex; about 207–260 m long, 195–215 m wide; with many short setae (pss) (each perhaps 25 m long) and small sensilla (psp) near apex. Penial sheath with a ventral slit through which aedeagus emerges. Aedeagus (aed) strongly sclerotised, broad, widening basally, probably with a ventral extension to a basal rod (bra); aedeagus about 250–275 m long, 80 m wide, with an eversible endophallus (eph) lying within abdomen, with rather few spines.

Comment

The male of this species of Margarodes (thought likely to be that of M. chukar La Rivers ) is unusual within the hypogeal margarodids in having the following combination of characters: (i) antennae unusually short, with each segment wider than long; (ii) absence of bifurcated setae on all legs (as on D. tanganyicus ); (iii) presence of a group of campaniform sensilla on all tarsi; (iv) absence of tibial spurs; (v) claws on meso­ and metathoracic legs long and blade­like, each with 3 or 4 digitules; (vi) absence of tarsal digitules; (vii) reduction in structure of thoracic spiracles; (viii) presence of abdominal spiracles on segments I–V, and (x) large size of abdominal spiracles.

Figures

FIGURE 11. Male Margarodes?chukar La Rivers. Letters as for Fig. 6.