Aphthargelia Hottes

Jensen, Andrew S., 2013, The aphid genus Aphthargelia Hottes (Hemiptera: Aphididae), with one new species, Zootaxa 3701 (3), pp. 381-392 : 382-383

Aphthargelia Hottes

Thargelia Oestlund, 1923: 127 . Type species: Aphis albipes Oestlund 1887 , a synonym of Aphis symphoricarpi Thomas 1878 , by original designation.

Aphthargelia Hottes 1958: 43 . Replacement name for Thargelia Oestlund , homonym of Thargelia Puengelev, 1899 .

Diagnosis. Apterae with mostly dark, sclerotized, and reticulated dorsum; antennae without secondary sensoria and only apical portions of segments III–V and all of VI pigmented; lateral tubercles, often very large, on thoracic segments and abdominal segments II–VI; siphunculi dark pigmented, about as long as or shorter than cauda, with apical ½ or more usually clavate; cauda pigmented or pale, with 10–20 setae (rarely less than 10) arranged haphazardly; femora and tibiae dark apically, tarsi dark, with 3,3,3 tarsal I setal formula. Alatae with dark dorsal bands and blotches on abdomen that are faintly reticulated; head, thorax, legs, siphunculi mostly dark; a.s. III–V with secondary sensoria, mostly restricted to one side of each segment.

Relationship with, and keys to, apterae and alatae of similar genera in North America

V.F. Eastop in Hodjat (1981) provided a useful key that included A. symphoricarpi , Pseudobrevicoryne , and several species of Brevicoryne . Such a key is important because these genera are morphologically similar, and in some cases share links to host plant families (e.g. Aphthargelia and two species of Brevicoryne feed on Caprifoliaceae ). Below is a key taking into account species of Macrosiphini genera occurring in North America that might be confused with Aphthargelia . Characters in common among these genera include the clavate (sometimes only slightly), often pigmented, siphunculi without reticulations that are similar in length to the cauda; the mostly smooth head capsule with low to moderate antennal tubercles; and apterae without sensoria on a.s. III. Some genera of Aphidini are also superficially similar, such as Rhopalosiphum , but these can be quickly separated from the genera in the keys below by 1. lateral tubercles on abdomen, when present, larger on segments I and VII than on II– V, and 2. the distance between abdominal spiracles II and III being less than twice the distance between spiracles I and II (i.e. two of the diagnostic characters in separating Macrosiphini and Aphidini ; Shaposhnikov, 1965).

Apterous viviparae

1. Spinal setae on abdomen with markedly expanded tips and on at least tergites VII and VIII mounted on distinct tubercles; tergum pale, not reticulated; on Brassicaceae and Chenopodiaceae in Washington State....................... Landisaphis

- Spinal setae on dorsum either blunt or pointed, and not on distinct tubercles; tergum pale or pigmented, with or without reticulation; on various hosts 2

2. Dorsum with dark reticulated shield, bands, or mix of bands and blotches, at least on abdominal segments II–V; lateral tuber- cles present on abdominal segments II–VI; cauda more or less triangular, usually with more than 10 setae; on Symphoricarpos or Aconogonon ............................................................................. Aphthargelia

- Dorsum pale or with various cross bands or blotches but these not reticulated; lateral tubercles absent on some or all abdominal segments II–V (rarely weak on all segments II–V); cauda variously shaped, with less than 10 setae 3

3. Cauda long, parallel-sided, length subequal to siphunculus..................................................... 4

- Cauda triangular, not parallel-sided....................................................................... 5

4. Siphunculi longer than cauda; posterior margin of venter of prothorax with dark spot; on Caprifoliaceae and Apiaceae .................................................................................................. Hyadaphis

- Siphunculi shorter than cauda; posterior margin of venter of prothorax without dark spot; on Chenopodiaceae .... Hayhurstia

5. Dorsum with dark dorsal bands or at least dark spots and intersegmental muscle attachment plates; tarsal I setal formula 3,3,3; on Brassicaceae .............................................................................. Brevicoryne

- Dorsum without dark bands or spots except tergites VII and VIII sometimes with faint pigment; tarsal I setal formula 3,3,2. 6

6. Siphunculi longer than cauda; on Brassicaceae ........................................................ Lipaphis

- Siphunculi shorter than cauda; on Lonicera (and apparently Symphoricarpos )............ Hyadaphis tataricae (Aizenberg)

Alate viviparae

1. Spinal setae on abdomen with markedly expanded, or at least broad-flattened, tips and on at least tergites VII and VIII mounted on distinct tubercles; tergum pale, not reticulated; on Brassicaceae and Chenopodiaceae in Washington State.... Landisaphis

- Spinal setae on dorsum either blunt or pointed, and not on distinct tubercles; tergum pale or pigmented, with or without reticulation; on various hosts................................................................................. 2

2. Dorsum of abdomen with dark reticulated bands and blotches covering much of most segments (these marking sometimes reduced in very small specimens); cauda with more than 10 setae (rarely with fewer); tarsal I setal formula 3,3,3; on Symphoricarpos or Aconogonon ....................................................................... Aphthargelia

- Dorsum pale or with lateral and/or pleural blotches, or more or less complete transverse bands, but these not reticulated; cauda with less than 10 setae; tarsal I setal formula usually 3,3,2, when 3,3,3, a.s. IV without sensoria 3

3. Antennal segment IV with sensoria....................................................................... 4

- Antennal segment IV without sensoria..................................................................... 5

4. Siphunculi swollen distally or more or less barrel-shaped; median ocellus projecting beyond antennal tubercles; on Caprifoliaceae and Apiaceae ............................................................................ Hyadaphis

- Siphunculi nearly cylindrical, slightly swollen often on one side; antennal tubercles more prominent than median ocellus; on Brassicaceae ................................................................................... Lipaphis

5. Cauda long, parallel-sided, longer than siphunculi; on Chenopodiaceae ................................... Hayhurstia

- Cauda more or less triangular, subequal to or shorter than siphunculi; on Brassicaceae ...................... Brevicoryne

Comments. Phylogenetic relationships among these genera are not clear, due mostly to lack of detailed study. Three of these genera have host plant connections to Caprifoliaceae : Aphthargelia with Symphoricarpos , and Brevicoryne and Hyadaphis with Lonicera . There are no clear morphological distinctions between Hayhurstia and Hyadaphis ; their separation in this key and over the years apparently tied entirely to host plant association ( Chenopodiaceae for the former, Caprifoliaceae and Apiaceae for the latter). A similar lack of morphological distinction may exist with Lipaphis and Hyadaphis , although this author lacks material of these Palearctic genera for adequate study of the issue.

Cedoaphis oviparae and fundatrices are sometimes confused with Aphthargelia (apterae and alatae are easily separated from Aphthargelia by their cylindrical siphunculi and sensoria on a.s. III in apterae). This confusion is due to the specialized morphology of these morphs and relatively poor coverage in the literature. In fact, the entire genus Cedoaphis is more complex than the literature suggests, with potentially undescribed species and biology in western North America. Presently, Cedoaphis from Symphoricarpos can only reliably be identified to genus. One feature that separates all morphs of these two genera amongst material this author has seen is that hind tarsal segment I has 3 setae in Aphthargelia but 2 setae in Cedoaphis . The fundatrix of Cedoaphis species this author has collected have antennae with more or less 4 segments, sometimes a slight division occurring in the 3rd segment, with compound eyes reduced to only about ten facets, and a very pale globose body. They live in tightly curled apical leaves, producing copious young. This contrasts with the illustration of the fundatrix identified as C. incognita from Palmer (1952) which shows 6-segmented antennae. Cedoaphis oviparae seen so far have 5- segmented antennae (compared to 6 in Aphthargelia ) with a strange hump-backed appearance in life that clearly sets them apart from Aphthargelia oviparae.