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Pleotrichophorus triangulatus Corpuz-Raros & E. F. Cook 1974

Comprehensive Description

provided by Smithsonian Contributions to Zoology
Pleotrichophorus triangulatus

DIAGNOSIS.—This species is distinctive with its short (.08 mm), basally broad, acutely pointed rostrum IV+V and short (.09–.11 mm) cornicles that are about ⅓ the cauda in length. It resembles P. patonkusellus in the number of df setae (36, m = 34.89 ± 2.45, n = 18 in said species) and the dense widely expanded funnel- to fan-shaped body setae; but differs in the shape and size of rostrum IV+V (.09–.11 mm, m = .100, n = 33 and slightly convex-sided in P. patonkusellus), and in having a relatively smaller co/ca ratio (.36–.44, n = 2 vs. .80 ± .03, n = 33 in P. patonkusellus).

DESCRIPTION.—Apterous Viviparous Female (based on a single female, the holotype): Color in life green (collection data); cleared and stained specimen with pale body, apex of rostrum, antennae from tips of a.s.V and entire tarsi brown. Body length 1.70, width across eyes .43 mm. Head with rather poorly developed mesofrontal and laterofrontal tubercles; mf 3, lf 2 on each side, vlf 1p, df 36, vf 6, pc 2p, md obscured by legs, ac 4; dorsal setae widely expanded, funnel- to fan-shaped, anterior ones slightly longer, more distinctly petiolate than posterior ones; ventral setae with vf and vlf shaped like df’s, remainder attenuate; mf .0286–.0352 and df–1 both .0330 mm long. Antennal segment I weakly produced mesodistally, faintly imbricate, bearing 7 blunt or slightly knobbed setae in addition to usual pointed one on dorsum. A.S.II with setae. A.s.III .40 mm long; with short, blunt or knobbed setae, longest about ⅓ basal diameter of segment; with 1 small sensorium. A.s.IV and V subequal (.31 and .30 mm, respectively), about ¾ length of a.s.III; a.s.VI with unguis (.50 mm) slightly less than 4 times base (.13 mm) in length.

Dorsal body integument finely striate, minutely spiculate; but spicules becoming more conspicuous caudally; setae rather dense, funnel- to fan-shaped, without distinct stems (Figure 183). Cauda .35 mm long, stoutly elongate, without noticeable basal constriction, broadly rounded at apex; spiculate; with 2 lateral pairs and 2 posterodorsal setae. Cornicles .09 and .11 mm long, about ⅓ as long as cauda; cylindrical, almost uniform in diameter; imbricate-spiculate, spicules rather small, sharply pointed, contiguous. Legs with 3, 3, 3 hairs on first tarsal joints (counts from nymphal paratypes); hind tibiae and hind tarsi missing. Rostrum IV+V .08 mm long, about .07 mm wide at base, tapering to acute tip, with sides straight, thus appearing triangular.

Alate Viviparous Female: Unknown.

Sexuales: Unknown.

HOST.—Agoseris sp.

DISTRIBUTION.—California, Eldorado Co. TYPES.—Holotype: apt.v.f., Kit Carson Camp, Eldorado Co., California, 18–VIII–1931, on Agoseris sp. Paratypes: 3 apt.ny. with same data and mounted on same slide as holotype. Types in EOE collection.

Pleotrichophorus utensis (Pack and Knowlton)

Capitophorus utense Pack and Knowlton, 1929:201 [type: apt.v.f., Loa, Utah, 26–VI–1926, GFK, on Gutierrezia longtfoha; in USNM].

Capitophorus utensus Pack and Knowlton.—Knowlton and Smith, 1936a: 112.

Capitophorus utahensis [sic] Pack and Knowlton.—Knowlton and Smith, 1937:152 [misspelling].

Capitophorus utensis Pack and Knowlton.—Palmer, 1952:272 [emendation].

Pleotrichophorus utensis (Knowlton and Pack) [sic].—Hille Ris Lambers, 1969:167–179 [Knowlton consistently mistaken as senior author].

Capitophorus magnautensis Knowlton and Smith.—Knowlton, 1954:8 [in part; specimens recorded from Sisters. Oregon seen and determined as P. utensis rather than P. magnautensus].

DIAGNOSIS.—This species is distinctive in the combination of the following characters: a short, stout, blunt-tipped rostrum IV+V that is about ⅔ (m = .67 ± .02, n = 23) the length of hind ta–2; a rather small co/ca ratio (1.37 ± .05, n = 35); entirely dark cornicles; the presence of few df setae (8.05 ± .002, n = 19), and relatively sparse body setae; and the presence of 1 or 2 flattened posterodorsal caudal setae. It may be mistaken for P. pycnorhysus especially where spinopleural abdominal papillae are poorly developed but the shape of its posterodorsal caudal setae and the shorter and entirely dark (only apices dusky in P. pycnorhysus) cornicles are distinctive. Its differences from P. acanthovillus are described under that species.

DESCRIPTION.—Apterous Viviparous Female: Color in life green (Pack and Knowlton, 1929: 201); cleared specimens pale with tips of rostrum and tibiae, entire tarsi and cornicles and antennae from near bases of a.s.III brown. Body 1.55–2.18 (1.80, n = 17) mm long, .45–.53 (.490, n = 19) mm wide across the eyes. Head with poorly developed frontal tubercles; mf 1p, lf 1–3 (usually 2) on each side, vlf 1p, df 7–9 (8.05 ± .002, n = 19), vf 6–11 (usually 8), pc 2p, ac 4 or 5, md 3–4 (usually 3) on each side; dorsal setae rather small, slightly expanded apically, ventral setae more elongate, knobbed or pointed; mf .0088–.0220 (.0140, n =19), and df–1 .0110–.0242 (.0191, n = 37) mm long. Antennal segment I produced mesodistally, smooth, and with 6–14 (usually 11) blunt or knobbed setae in addition to basal pointed one on dorsum. A.s.II with usually blunt or knobbed setae. A.s.III with short knobbed setae, longest about ½ basal diameter of segment; with 1–9 (3.33, n = 33) sensoria. A.s.IV and a.s.V subequal, ⅔ to ¾ length of a.s.III; a.s.VI with unguis averaging 4¼ times (range of 3½ to 5, n = 26) as long as base.

Dorsal body integument rather smooth on disk, becoming striate-spiculate caudally; usually uniformly flattened but spino-pleural thickenings on papillae may be sometimes present on posterior segments; setae small, funnel- to fan-shaped, sparse, with 2 or 3 setae in spinal and pleural areas, more variable numbers on sides. Cauda elongate, with slight basal constriction, rounded apex; spiculate; with 2 lateral pairs of pointed setae, 0–2 (1.17, n = 18) expanded posterodorsal setae. Cornicles .31–.47 (.389, n = 37) mm long, 1.13–1.63 (1.37 ± .05, n = 35) times as long as cauda; cylindrical, widest at apex; faintly imbricate-spiculate, dark brown from near bases. Legs with 3, 3, 3 setae on first tarsal joints. Rostrum IV+V short, robust, blunt at apex; .09–.10 (.092, n = 20) mm long, averaging ⅔ (.67 ± .02, n = 23, range of .60–.75) times as long as second hind tarsal joint; with 1 basal, 2 dorsal, and 3 lateral pairs of subequally long setae.

Measurements (in mm) of 10 specimens on Gutierrezia: BL 1.55–1.95 (1.71), We .45–.53 (.486); a.s.III .48–.64 (.552), a.s.IV .36–.50 (.433), a.s.V .34–.43 (.390), a.s.VI .11–.15 (.134) + .47–.62 (.559); cornicles .31–.40 (.368), cauda .24–.30 (.271); hind tibiae .91–1.11 (1.00), hind ta–2 .12–.15 (.134), and rostrum IV+V .09–.095 (.091). Proportions of a.s.III:IV:V, 1: .72–.88 (.79): .67–.75 (.71); VIu/VIb 3.64–5.09 (4.20); co/ca 1.13–1.63 (1.34), rostrum IV+V/ hind ta–2 .60–.75 (.68).

Alate Viviparous Female: Not known.

Sexuales: Not known.

HOSTS.—Chrysothamnus viscidiflorus (subsp. stenophyllus, according to Palmer, 1952:272), Gutierrezia longifolia, G. sarothrae, and Gutierrezia sp.

DISTRIBUTION.—P. utensis has been collected from many localities in southern Utah and sporadic records exist from northern Utah, also Idaho and Oregon.

TYPES.—The original type-series from Loa, Utah, was unavailable at the time this research was completed. A lectotype has not been selected.

SPECIMENS EXAMINED.—All collected by GFK from: OREGON: Sisters, 4 apt.v.f., 24–VIII–1944, on Chrysothamnus viscidiflorus (GFK coll.). UTAH: Bicknell, 4 apt.v.f., 21–VI–1955, on Gutierrezia (EOE coll.); Grouse Creek, 3 apt.v.f., 13–VIII–1932, on C. viscidiflorus (USNM); Nioche, 4 apt. v.f., 24–VIII–1944, on C. viscidiflorus (GFK coll.); 10 mi W of Snowville, 6 apt.v.f., 7–VI–1930, on Gutierrezia (USNM); and Wild Cat Canyon, Beaver Co., 2 apt.v.f., 8–VIII–1936, on C. viscidiflorus (EOE coll.).
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bibliographic citation
Corpuz-Raros, Leonila Alzate and Cook, Edwin F. 1974. "A revision of North American Capitophorus van der Goot and Pleotrichophorus Börner (Homoptera: Aphididae)." Smithsonian Contributions to Zoology. 1-143. https://doi.org/10.5479/si.00810282.156