A new species of Macrosiphum (Hemiptera: Aphididae) living on Silene (Caryophyllaceae) Author Jensen, Andrew S. text Zootaxa 2022 2022-09-12 5183 1 75 89 journal article 140854 10.11646/zootaxa.5183.1.9 b51a5b57-15b9-4238-94b8-23780b46d824 1175-5326 7070529 8F77AAD3-0A6F-4018-A2B8-E67335FBCE85 Macrosiphum ginajo n. sp. Fundatrix. Appearance in life: medium green. When macerated, as in apterae. Slide mounted, 4 specimens measured: Measurements of body, appendages, setae, etc. see Table 2 . Antennae with segment I more or less smooth except a small cluster of small spinules ventrally near base, fewer than in most apterae. Tarsi with 3–4 setae on segment I (of 4 measured specimens, fore,mid,hind tarsi patterns were: 3,3,3: 2 specimens ; 3,4,4: 1 specimen ; 4,3,3: 1 specimens ). Spiracles on ABD 1 and 2 about 2–3 spiracle widths apart. Siphunculi with ~8 rows of apical reticulation. Cauda on the broad end of the spectrum of variation in apterae. Abdomen usually without spinal tubercles on tergites 7 and 8. Subgenital plate with row of postero–marginal setae, 1 pair of anterior setae, and 0–1 setae on its disk. Otherwise as in apterae. TABLE 2. Biometric data for the fundatrices, oviparae, and alate males of Macrosiphum ginajo . All measurements in microns.

Number of specimens measured		Fundatrix 4	Oviparae 10	Males 5
Length of body excluding the cauda		2982–3360	1962–2652	1890–2448
Antenna	Length ANT III	792–906	564–834	540–762
Length ANT IV	534–690	450–666	480–672
Length ANT V	504–540	444–582	432–576
Length BASE	146–174	130–166	115–150
Length ANT PT	768–870	780–984	822–1152
Length ANT IV/Length ANT III	0.65–0.76	0.78–0.92	0.82–0.89
Length ANT V/Length ANT III	0.60–0.64	0.67–0.82	0.71–0.80
Length BASE/Length ANT V	0.29–0.32	0.26–0.32	0.25–0.29
Length ANT PT/Length ANT III	0.92–0.97	1.04–1.62	1.40–1.61
Rhinaria ANT III	3–5	2–5	42–57
Rhinaria ANT IV	0	0	0–6
Rhinaria ANT V	0	0	13–19
BD III	40–43	36–43	36–43
Rostrum	Length R IV+V	150–166	134–162	146–162
Length R IV+V/Length HT II	1.22–1.31	1.13–1.42	1.26–1.46
Hind leg	Length hind femur	1140–1248	810–1128	768–1032
Length hind tibia	2100–2340	1482–2220	1458–2070
Length HT II	123–126	103–126	103–123
Width hind tibia in middle	55–59	47–71	32–43
Siphunculus	Length	996-1104	618–1008	468–642
Length/Length ANT III	1.22–1.26	1.01–1.21	0.83–0.90
Cauda	Length, including the soft part	492–546	264–390	150–228
Setae	No. R IV+V accessory setae	12–16	9–15	14–17
No. setae on cauda	10–11	11–17	7–11
No. setae on ABD TERG 8	5–6	7–10	6–8
No. of lateral setae on ANT I	2–3	1–3	1–3
No. setae medial aspect ANT tubercle	2–3	2–3	2–3
No. setae on ANT tubercle ventrally	1	0–1	1
Length longest seta ANT tubercle	43–51	40–55	28–40
Length longest seta ANT III	36–40	32–43	24–36
Length dorsal seta middle hind tibia	47–55	36–47	40–55

...Continued on the next page TABLE 2. (Continued)

Number of specimens measured	Fundatrix 4	Oviparae 10	Males 5
ANT tubercle seta length/BD III	1.09–1.18	1.00–1.30	0.78–0.91
Length longest seta ANT III /BD III	0.81–1.00	0.80–1.11	0.60–1.00
Hind tibia: length dorsal seta/width	0.80–1.00	0.60–1.00	1.00–1.33
Length of seta, ABD TERG 3	32–43	32–43	32–47
Length of seta, ABD TERG 8	40–47	47–63	43–63
Length ABD 8 seta/BD III	0.91–1.10	1.18–1.67	1.20–1.45

Apterous vivipara. Appearance in life: medium green or reddish brown. When macerated, ANT I pale to dusky, ANT II rarely dusky, ANT III sometimes darker around rhinaria, all of ANT IV and V sometimes dusky to brown, antennal joints III–IV and IV–V brown, ANT VI brown. Head capsule mostly pale, sometimes dusky around bases of antennae; ocular tubercles brown. R III and R IV+V brown. Femora dusky to light brown except basal ~¼ pale, sometimes darker brown dorso–apically. Tips of tibiae brown, remainder dusky to light brown. Tarsi brown. Siphunculi more or less pale to light brown on apical ~½. Other body parts pale. Slide mounted, 20 specimens measured: Measurements of body, appendages, setae, etc. see Table 1 . Antennae with segment I ( Figs. 1 , 7–8 ) more or less smooth except a cluster of small spinules ventrally near base and sometimes a few spinules medially near apex; ANT II ( Figs. 7–8 ) with strong broad spinules/small imbrications on apical ½ ventrally, sometimes reduced in middle, spinules usually also present dorsally near apex; ANT III ( Figs. 7–8 ) with small spinules near base, remainder more or less evenly covered in faint imbrications, rhinaria scattered over about ¼–⅓ of segment; ANT IV–VI with imbrications becoming more prominent; antennal setae capitate (capitate tips collapsed by caustic clearing treatments). Head with ANT tubercles as in Fig. 1 ; small spinal tubercles present or absent; dorsal setae long, blunt, tips less prominent than on antennae; ventral and dorsal setae more or less the same shape; a few to a few dozen spinules sometimes present ventrally between mouthparts and ANT tubercles; a small patch of spinules sometimes present posterio–ventrally on each side of mouthparts. Rostrum reaching posterior of mesocoxae; segment II with stylet groove spinulated, segments III and R IV+V without ornamentation; setae on rostrum pointed; R IV+V long, gradually tapering ( Table 1 , Fig. 3 ). Prothorax usually with faint to prominent lateral tubercles. Thorax with dorsum slightly wrinkled, setae appearing blunt, slightly capitate before clearing; setae on coxae and trochanters more or less pointed; femora with setae thick and blunt to slightly capitate, 3–4 ventral ones longer and thicker than others, ornamentation of spinules and small imbrications over apical ~½ anteriorly, this ornamentation more extensive on hind femur, extending around to posterior. Tibiae with setae thick and capitate near bases, more pointed near apices. Tarsi ( Fig. 6 ) with 3–5 setae on segment I (of 20 measured specimens, fore,mid,hind tarsi patterns were: 3,3,3: 2 specimens ; 3,3,4: 4 specimens ; 3,4,3: 1 specimen ; 3,4,4: 1 specimen ; 3,5,4: 1 specimen ; 3,5,5: 1 specimen ; 4,3,3: 2 specimens ; 4,3,4: 1 specimen ; 4,3,5: 3 specimens ; 4,4,5: 2 specimens ; 5,3,4: 1 specimen ; 5,5,5: 1 specimen ); protarsal II with 2 (rarely 3) pairs of dorsal setae, imbrications smooth, rarely with faint spinules. Abdomen with tergum membranous, smooth; dorsal setae thick and blunt to slightly capitate, ventral setae pointed; segments 3–6 usually with small distinct lateral tubercles. Spiracles on ABD 1 and 2 about 2 spiracle widths apart. Siphunculi ( Fig. 4 ) with ~8–12 rows of apical reticulation, faintly ribbed or spinulate imbrications more basally, becoming smaller and more ribbed or spinulate on basal ~¼. Cauda shape varying from broad basally and more or less triangular (e.g. Fig. 11 ), to parallel–sided and finger–like (e.g. Fig. 12 ); dorsal ornamentation of ribbed imbrications about 8 to 10 across width at middle; ventral ornamentation of spinules mostly single but some in groups of 2–3. Abdomen usually with faint spinal tubercles on tergites 7 and 8. Subgenital plate with row of postero–marginal setae, 1 pair of anterior setae, and 1 to several setae on its disk. Middle pair gonapophyses fused. Alate vivipara. Appearance in life: medium green or reddish brown. When macerated, ANT I brown, ANT II dusky to light brown, ANT III brown except extreme base, sometimes obviously darker around rhinaria, all of ANT IV–VI brown. Head capsule mostly dusky, brown around ocelli and bases of antennae, ocular tubercles brown. R III and R IV+V brown. Thoracic plates light brown to brown. Femora pale at base, darkening toward apex, apical ~¼ brown, darker dorsally and ventrally. Tibiae brown, paler in middle. Tarsi brown. Siphunculi dusky to brown on apical ~½. Other body parts pale. FIGURE 1–6. Macrosiphum ginajo : 1, head and ANT I of aptera, ventral surface on the left featuring the cluster of small spinules, dorsal surface on the right; 2, head and ANT I of alata, dorsal surface; 3, R III and R IV + V of aptera; 4, siphunculus of aptera; 5, ANT III of alata; 6, tarsus of aptera. All scale bars equal 100 microns. FIGURE 7–10. Macrosiphum ginajo : 7, ANT I–II and basal part of ANT III of aptera showing typical ornamentation on ANT I–II; 8, ANT I–II and basal part of ANT III of aptera showing a specimen with reduced ornamentation on ANT II and an unusual tuberculate small rhinaria on ANT III; Macrosiphum aetheocornum : 9, ANT I–II and basal part of ANT III of aptera, a specimen with relatively heavy ornamentation on ANT II common tuberculate small rhinaria on ANT III; 10, ANT I–II and basal part of ANT III of aptera, a specimen with relatively typical ornamentation on ANT II. The scale bar equals 100 microns and applies to all four figures. FIGURE 11–13. Macrosiphum ginajo : 11, cauda of aptera, a specimen with cauda broad basally and triangular–shaped; 12, cauda of aptera, a specimen with a more finger–like parallel–sided cauda; Macrosiphum aetheocornum : 13, siphunculus of aptera. All scale bars equal 100 microns. Slide mounted, 16 specimens measured: Measurements of body, appendages, setae, etc. see Table 1 . Antennae with segment I more or less smooth except a cluster of small spinules ventrally near base and sometimes a few near medial margin near apex, overall fewer spinules than in apterae; ANT III ( Fig. 5 ) with rhinaria scattered over about ⅔–⅘ of segment. Head with ANT tubercles as in Fig. 2 ; a few spinules sometimes present ventrally between mouthparts and ANT tubercles; ocelli present, normal. Rostrum reaching mesocoxae. Thoracic flight–related structures normal, wings normal with media twice–branched. Tarsi with 3–5 setae on segment I (of 16 measured specimens, fore,mid,hind tarsi patterns were: 3,3,3: 2 specimens ; 3,3,4: 4 specimens ; 3,4,3: 2 specimens ; 3,4,4: 1 specimen ; 4,3,3: 3 specimens ; 4,3,4: 2 specimens ; 5,3,4: 1 specimen ; 5,4,5: 1 specimen ). Cauda more or less as in apterae but narrower than most. Abdomen usually with 1–2 faint spinal tubercles on tergites 7 and 8. Otherwise as in apterae. Ovipara. Appearance in life: orange, brownish orange, pale beige. When macerated, ANT I pale to dusky, ANT II rarely dusky, ANT III sometimes darker around rhinaria, all of ANT IV and V often dusky to brown, antennal joints III–IV and IV–V brown, ANT VI brown. R III and R IV+V brown. Femora dusky to light brown except basal ~¼ pale, sometimes darker brown dorso–apically. Tips of tibiae brown, remainder dusky to light brown except metatiba brown throughout area with scent plaques. Tarsi brown. Head capsule mostly pale, ocular tubercles light brown. Siphunculi more or less pale to light brown on apical ~⅓. Other body parts pale. Slide mounted, 10 specimens measured: Measurements of body, appendages, setae, etc. see Table 2 . Antennae with segment I more or less smooth except a cluster of small spinules ventrally near base and sometimes a few spinules medially near apex, fewer spinules than in most apterae; ANT II with strong broad spinules/small imbrications on apical ½ ventrally, often reduced in middle, a few spinules usually also present dorsally near apex; antennal setae nearly pointed, with very narrow collapsed glandular tips. Head with ANT tubercles slightly less prominent than in apterae; dorsal setae long, nearly pointed, tips less prominent than on antennae. Rostrum reaching metacoxae. Thorax with dorsum smooth to slightly wrinkled, setae appearing blunt, faintly capitate before clearing; femora with ornamentation of spinules and small imbrications over apical ~½ anteriorly, this ornamentation more extensive on hind femur, extending around to posterior, ornamentation less than in apterae. Tibiae with numerous scent plaques scattered over about basal ½, this area slightly swollen compared to apical ½. Tarsi with 3–5 setae on segment I (of 10 measured specimens, fore,mid,hind tarsi patterns were: 3,3,3: 4 specimens ; 3,3,5: 1 specimen ; 3,4,5: 1 specimen ; 4,3,3: 2 specimens ; 4,4,4: 1 specimen ; 4,3,4: 1 specimen ). Spiracles on ABD 1 and 2 about 2–3 spiracle widths apart. Siphunculi with ~8–10 rows of apical reticulation. Cauda shape varying in a similar way as in apterae. Abdomen usually with 1–2 faint spinal tubercles on tergites 7 and 8. Subgenital plate with row of postero–marginal setae, 1 pair of anterior setae, and ~10–20 setae on its disk. Otherwise as in apterae. Alate male. Appearance in life: mottled orange and green. When macerated, ANT I brown, ANT II light brown, ANT III brown except extreme base, which is pale to dusky, all of ANT IV–VI brown. R III and R IV+V brown. Thoracic plates light brown to dark brown. Femora pale at base, darkening toward apex, apical ~¼ brown, darker dorsally and ventrally. Tibiae brown, lighter brown in middle. Tarsi brown. Head capsule mostly brown, darkest around ocelli and bases of antennae, ocular tubercles brown. Siphunculi dusky to brown, darker on apical ½. Abdomen with the following dusky to brown: patches of variable size spinally, pleural muscle–attachment plates, lateral sclerites including ante– and post–siphuncular sclerites, small separate spiracular plates, and variable dusky to brown ventral patches pleurally on most segments. Cauda dusky to brown. Genitalia dusky to light brown. Other body parts pale. Slide mounted, 5 specimens measured: Measurements of body, appendages, setae, etc. see Table 2 . Antennae with ANT III with rhinaria scattered over entire length of segment, ANT IV with rhinaria, when present, grouped near apex, ANT V with rhinaria also grouped apically. Tarsi with 3–5 setae on segment I (of 5 measured specimens, fore,mid,hind tarsi patterns were: 3,3,3: 1 specimen ; 3,3,5: 1 specimen ; 5,4,4: 1 specimen ; 4,3,3: 1 specimen ; 4,4,3: 1 specimen ). Cauda narrower and shorter than in apterae and alatae. Abdomen usually with 1–2 faint spinal tubercles on tergites 7 and 8. Genitalia normal. Otherwise as in alatae. Type material and material examined ( all collected by the author in the U.S.A. ). Holotype slide, AJ8752 , OREGON , Lake County , Gearhart Mountain , ex Silene , 16 July 2016 (2 ap, 1 al), deposited in the USNM . Paratypes (depositories other than the author’s collection so noted): CALIFORNIA: AJ 11361, AJ11362 , AJ11363 , Lassen County , Modoc National Forest, South Warners, Lost Lake, ex Silene , 11 August 2019 (7 ap) ; AJ11313 , AJ11314 , Plumas County , Plumas National Forest , Grizzly Ridge , ex Silene , 4 August 2019 (4 al); IDAHO : AJ5234 , AJ5235 , AJ5236 , Shoshone County , Crater Peak , Forest road 301, ex Silene , 8 September 2010 (10 ap, 1 al) ; AJ4720 , Benewah County , St. Joe Baldy , ex Silene , 8 August 2010 (1 al); OREGON : AJ11455 , AJ11456 , AJ11476 , AJ11477 , AJ11478 Lake County , Fremont N.F. , Gearhart Mt. Trail , ex Silene , 7 September 2019 , A.S. Jensen (6 ap, 2 al, 8 o, 3 am) ; AJ8750 ( BMNH ), AJ8751 , Lake County , Gearhart Mountain , ex Silene , 16 July 2016 (4 ap, 1 al) ; AJ12315 , Lake County , Fremont National Forest , near Rd. 094 on Cottonwood Meadow Lake , ex Silene , 6 September 2020 (2 ap) ; AJ9486 , AJ9487 , Lake County , Fremont National Forest , Gearhart Mt. Trail , ex Silene , 16 July 2017 (4 al) ; AJ12330 , Lake County , Fremont National Forest , Rd. 3724 at Rd. 154 near Cottonwood Meadow Lake , ex Silene , 13 September 2020 (2 ap, 2 o) ; AJ9662 , AJ9663 , AJ9665 Lake County , Fremont National Forest, Gearhart Mt. trail, ex Silene , 17 September 2017 (1 ap, 6 o, 1 am) ; AJ12039 , AJ12040 , Wheeler County , Ochoco National Forest , Spanish Peak , ex Silene , 11 July 2020 (4 f) ; AJ12046 , AJ12047 , AJ12048 , AJ12049 , Wheeler County , Ochoco National Forest , Rim Trail near Spanish Peak , ex Silene , 12 July 2020 (7 ap, 4 al); WASHINGTON : AJ3391 , AJ3392 , Kittitas County , Alpine Lakes , ex Silene , 31 August 2008 (4 ap, 2 al) . Other material examined: additional slides from the collections recorded above but that do not contain specimens measured for this description. Etymology. The species name is in honor of Gina Rone, who has supported hikes and camping outings aimed at finding this species for the past twelve years, waiting patiently in the forest as I search for Silene and its aphids. A geologist and forest soil scientist, Gina has helped me understand the ecology of this and many other aphids. For the purposes of the rules of nomenclature, the name should be considered an arbitrary combination of letters and treated as indeclinable. Biology and Distribution. This aphid lives without host alternation on glandular–sticky members of Silene , especially Silene oregana S. Watson. The full host range of M. ginajo is not known because the author has not been able to make accurate species identifications of all sampled plants. One sample from Shoshone County, Idaho was recorded as feeding on a Silene with pink flowers. This may have been Silene scouleri Hook. , which is sticky like S. oregana , occurs across the known range of M. ginajo , and has pink flowers. Many stands of non–sticky Silene (probably Silene douglasii Hook. ) have been searched for M. ginajo over the years, but without success. In the forests of Lake County, Oregon , where this aphid has been most thoroughly studied in the field, its S. oregana host plant occurs most commonly in association with white pine ( Pinus monticola Douglas ex D. Don ) or sugar pine ( Pinus lambertiana Douglas ) and often on soils associated with rhyolitic parent material. So far, this aphid is known from Washington , Oregon , California , and Idaho . The range of S. oregana also includes parts of Montana , Wyoming , and Nevada ( Hitchcock & Cronquist 1973 ), indicating that M. ginajo may occur in those states as well. Comments. Macrosiphum ginajo is unusual among Macrosiphum worldwide in the occurrence of more than 3 setae on first tarsal segments. When measuring and counting setae on just one side of each specimen, as done here for Tables 1 & 2 , there are examples of specimens with 3 setae on each tarsal segment I (i.e., possessing the formula 3,3,3), but this is uncommon. When evaluating all six tarsi on all measured apterae, none have 3 setae on all tarsi. Looking at other morphs, three fundatrices, one alata, and three oviparae were found with three setae on all first tarsal segments. On the other hand, no slides of M. ginajo (i.e., groups of 2– 4 specimens from the same locality and date), have all specimens with three setae on first tarsal segments. Therefore, this author considers first tarsal chaetotaxy to be useful in species recognition. Of North American Macrosiphum , M. ginajo is most similar to Macrosiphum aetheocornum . Detailed comparison of the two species can be seen in Figures 7–10 and 4 & 13 and Tables 1–4 . Similarities and differences between these species are discussed below in the comments on M. aetheocornum . Because aphids are mostly host–specific, it is important to present information for identifying aphids known from genera of host plants. I therefore present the following key to Macrosiphum recorded from Silene , modified from Blackman & Eastop (2006 & 2021 ) using their terminology and abbreviations (couplets 20–24 of the Sileneinhabiting aphid species key). A correction is also added to couplet 21 of Blackman and Eastop (2021) (couplet 22 below), clarifying that, based on data provided by Barjadze et al. (2017) , the second feature should have been the ratio of R IV+V length and HT II length. 20. SIPH with a subapical zone of polygonal reticulation........................................................21 – SIPH without polygonal reticulation..................................................................... 26 21. R IV + V 1.20 – 1.45 × HT II. At least one tarsal segment I with 4 or 5 setae (to confirm, check more than one specimen ) …...................................................................................... Macrosiphum ginajo – R IV+V less than 1.20 × HT II. Tarsal segments I with 3 setae.................................................22 22. ANT III with 10–33 rhinaria extending over most of length. R IV+V 0.60–0.84 × HT II............................ 23 – ANT III with 1–12 rhinaria concentrated near base or on basal half. R IV+V 0.83–1.02 × HT II...................... 24 23. SIPH 1.55–1.94 × cauda. (Al. with 36–43 secondary rhinaria on ANT III)........................ Macrosiphum eastopi – SIPH 1.22–1.58 × cauda. (Al. with 18–35 secondary rhinaria on ANT III)........................ Macrosiphum hartigi 24. ANT PT/BASE 3.1–4.8. SIPH 1.4–1.8 × cauda which bears 12–22 hairs...................... Macrosiphum penfroense – ANT PT/BASE 4.2–6.4. SIPH 1.7–2.3 × cauda which bears 8–16 hairs..........................................25 25. Femora usually with a dark spot or patch near apices. ABD TERG 2–3 with longest hair 26–56 μm, usually as long as or longer than ANT BD III. Subgenital plate with 2–13 hairs in addition to those on posterior margin........ Macrosiphum stellariae – Femora pale or only slightly dusky at apices. ABD TERG 2–3 with longest hair 21–37 μm, usually shorter than ANT BD III. Subgenital plate with 2(–4) hairs on anterior part......................................... Macrosiphum euphorbiae