Chionaspis brachycephalon Vea
Vea, Isabelle M., Gwiazdowski, Rodger A. & Normark, Benjamin B., 2013, Corroborating molecular species discovery: Four new pine-feeding species of Chionaspis (Hemiptera, Diaspididae), ZooKeys 270, pp. 37-58 : 40-42
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|Chionaspis brachycephalon Vea|
Morphogroup D in Gwiazdowski et al. (2011).
Type locality: Mexico, Durango state, Navios, 23°53.95'N, 105°2.83'W, on needle of Pinus cooperi Blanco, 24 September 2007, R. Gwiazdowski and A. Garcia Arévalo coll.
Holotype adult female, slide-mount in balsam. Original label: "D1765A, Mexico, Durango, Resturante "Los Pinos", Navios, 1.ix.2007, 23°53' 56.9"N, 105°02'49.6"W, R. Gwiazdowski, A. Garcia Arévalo, Pinus cooperi ", deposited at CNIN.
Paratype: Adult female, slide-mount in balsam. D1765B, same collection data as holotype, deposited at USNM.
Other material examined: Adult female, slide-mount in balsam. Original label "D1718A, Mexico: Mexico, Hwy 95 South of Tres Marias, 1.ix.2007, 19°01'37.5"N, 99°12'35.2"W, R. Gwiazdowski, D. Gernandt, Pinus pseudostrobus Lindl.", deposited at UMAM. Adult females on separate slides, D1718C, D and F, same collection data as D1718A, deposited at CNIN.
Chionaspis brachycephalon Vea differs from other Chionaspis by the following combination of characters (Table 1): small head, gland spine formula variable from 1-1-1 to 2-2-2 (median: 2-2-2), microduct formula also variable from 2-2-2 to 3-3-4 (median: 3-2-2); numerous marginal gland spines on abdominal segments 3 to 5, absent from abdominal segment 1 and 2; variable number of notches present on all pygidial lobes.
Field characters: All pine-feeding Chionaspis discussed here, including Chionaspis heterophyllae and Chionaspis pinifoliae , are indistinguishable by eye in the field. The adult female for all species possesses a white oystershell-shaped and slightly convex cover, with the amount of posterior expansion varying according to the diameter of host needles. Body elongate, color varying from yellow when immature to reddish brownish in specimens containing eggs, with lateral protrusion on the anterior abdominal segments. Found on needles.
Slide-mounted adult female (Figure 1), broadest at metathorax, with thoracic segments lobed laterally, prothorax becoming narrower towards the anterior, ending with a pointed head, giving the appearance of a reduced, shrunken head; length of holotype 1.33 mm, range (n= 6) 0.85 - 1.33 mm; maximum width of holotype: 0.63 mm; range (n=6) 0.45 - 0.66 mm.
Pygidium: Lobes. Posterior margin with 3 pairs of definite lobes (L1, L2 and L3), fourth pair (L4) appearing as series of low, sclerotized points; paraphyses absent. L1 separated by space 0.31 - 0.6 (0.4) times width of lobes, with a heavily sclerotized yoke, lateral and medial margins of L1 diverging from base to apex, medial margin convex with notches towards apex, lateral margin entire; L2 bilobed, smaller than L1, medial lobule larger than lateral, sometimes with notches, lateral lobule minutely notched; L3 bilobed, lateral lobule shorter than medial lobule, with minute notches, in some specimens appearing membranous or obsolete. Gland spines. Gland spine formula varying from 1-1-1 to 2-2-2 (2-2-2) (microduct formula varying from 2-2-2 to 3-3-4 (3-2-2)), gland spines projecting beyond L1; with 1 - 2 (2) gland spines on abdominal segment 5; without gland spines between L1. Ducts. Large macroducts in submedian area of segments 5 and 6 (with 5 - 10 (8) on segment 5 and 4 - 7 (5) on segment 6); in submarginal areas of segment 5 (with 8 - 10 (9)); marginal area of segments 5 to 7 (with 1 on segment 7, 2 on segment 6, 2 - 3 (2) on segment 5); absent on segment 8. Largest macroduct on segment 7 (between L1 and L2) 15 - 17.5 (17.5) μm long. Pygidial microducts always on venter in submarginal areas of segment 5 to 7, with 2 - 4 (2) ducts on segment 5, 1 - 3 (2) ducts on segment 6 and 1 ducts on segment 7; pygidial microduct absent from dorsum. Pores. Perivulvar pores with 5 loculi, in 5 groups, 1 median with 9-15 (13) pores, 2 anterolateral with 19 - 33 (23) pores, 2 posterolateral with 19 - 33 (25) pores. Anal opening. Located 6.8 - 10.2 (8.4) times length of anal opening from base of median lobes, diameter 15 - 20 (17.5) μm.
Dorsal setae: 2 setose on L1, 1 setose (15 μm) between lobules of L2 and L3 lobes. Ventral setae: 1 small on median lobe, 1 marginal at base of each gland spine cluster and 1 in submarginal area of each segment, 2 in submedian area of segment 6, half as long as dorsal setae; 2 pairs of setae in a row anterior to the vulva.
Prepygidium: Gland spines. Near each body margin on segments 3 and 4, absent from segment 1 and 2; with 2 - 6 (4) on segment 3 and 2-5 (4) gland spines on segment 4, all protruding from margin..Ducts. Macroducts of 2 sizes; large macroducts in submedian and submarginal areas of abdominal segments 3 and 4. Small macroducts in submedian area of any or all of segments 2 to 4, and in marginal areas from meso- or metathorax to segment 3. Prepygidial microducts present on venter and dorsum from segment 1 to 4, sparsely distributed.
Cephalothorax: Microducts present on venter and dorsum with a slight concentration around thoracic spiracles.Perispiracular pores with 3 loculi, anterior spiracles with 3 - 5 (5) pores, posterior spiracles with 1 - 5 (2) pores. Eyes represented by small sclerotized area, located on body margin at level near anterior clypeolabral shield. Antennae each with 1 long seta and 2 minute setae, distance between antennae 42.5 - 90 (57.5) μm.
Etymology. The epithet brachycephalon is a noun, derived from Greek, meaning "short head", from brachy- short + cephalon head. The epithet refers to the head shape of this species, which appears smaller than that of other pine-feeding Chionaspis .
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