Andricus lustrans Beutenmüller, 1913

Andricus lustrans Beutenmüller, 1913: 244; Zhang et al. (2022: 69). Type material deposited in USNM and ANSP;
Callirhytis lustrans (Beutenmüller); Weld (1926: 95).

The history of Acraspis vaccinii is far more complicated. Osten-Sacken (1862: 255) characterized a gall from post oak, Q. stellata (as Q. obtusiloba Michx.), found by him on a tree in Washington (p. 241) in October 1861, but did not provide a name, nor rear any adult wasps. Later, Ashmead (1887: 127, 136) provided a name for this species, duplicating Osten-Sacken’s (1862) description of the gall, and adding a short description of the apterous adult wasps. Ashmead’s unfortunate choice of “vaccinii” as specific epithet for this species was in reference to Osten-Sacken’s (1862) mention of the gall shape: “their shape may be compared to that of the flowers of Vaccinium”. Acraspis vaccinii was later transferred to Zopheroteras Ashmead, 1897 (Ashmead 1897: 261). Later, Ashmead (1903: 148) formally designated A. vaccinii as the type species of Zopheroteras; this act referred only to adults and did not mention the galls.

Almost in parallel, Kieffer (1902: 97) assigned Acraspis vaccinii to Trigonaspis Hartig, 1840 and, later, Dalla-Torre and Kieffer (1910: 393) considered Zopheroteras (galls and adults) a junior synonym of Trigonaspis. Weld (1922: 9) resurrected Zopheroteras and synonymized Parateras Ashmead, 1887 under Zopheroteras. In the same study, Weld (1922) mentioned that the gall that Ashmead (1887) had described for Acraspis vaccinii corresponded to galls of a winged species which Beutenmüller (1918: 329) had previously described as Andricus impositus Beutenmüller, 1918, and stated that the true gall of Zopheroteras vaccinii had not yet been described; this was supported by the observation that Ashmead’s A. vaccinii adult wasps were apterous (Fig. 1). Hence, Weld (1922) concluded that Ashmead (1887) had misidentified the gall and misassociated adults of his new genus Zopheroteras with the galls described as Acraspis vaccinii.

However, the name confusion of these wasps was still developing. Based on gall, adult morphology and host, Weld (1926: 95) synonymised Andricus impositus with Andricus lustrans and transferred A. lustrans (= A. impositus) to the genus Callirhytis Foerster, 1869. In the same paper, Andricus dimorphus var. verifactor Kinsey, 1922 was synonymized under Callirhytis lustrans and the galls of Acraspis vaccinii were identified as those of C. lustrans.

Weld (1951: 650) considered Acraspis vaccinii (galls only) as a nomen nudum, under C. lustrans. However, we consider that this nomen nudum assignment was an error as the galls were described under that name, but erroneously associated with the adults described therein, resulting in a mixed type series. Weld (1951: 643) indicated Acraspis vaccinii (adult female only) as the type species of Zopheroteras.

More recently, Burks (1979: 1095, 1106) considered the adult wasps of Acraspis vaccinii as Zopheroteras vaccinii, but the galls as Callirhytis vaccinii Burks, 1979, listing Andricus lustrans, A. impositus and A. dimorphus var. verifactor as junior synonyms of the latter, thus mysteriously regarding Ashmead’s name as valid for two different taxa. It can, however, be considered that Burks (1979) effectively established a new species, Callirhytis vaccinii, for the galls since he referred to Ashmead’s description of them, complying with Article 13.1.2 of the International Code of Zoological Nomenclature (ICZN 1999). Finally, Zhang et al. (2022: 69) re-established the name Andricus lustrans as a valid species, removing it from Callirhytis.

The International Code of Zoological Nomenclature (ICZN 1999: Article 72.4.1) specifies that the type series includes all specimens that the author included in the new taxon “whether directly or by bibliographic reference” (except any disclaimed by the author). Article 73.2.1 reinforces this broad concept of syntypes, including specimens representing the work of an animal if described before 1931 (Article 1.2.1). Ashmead (1887: 136) quoted Osten-Sacken’s description of the gall, rather than writing his own, but also described two adult specimens (implied to have been reared from similar galls), so both components were properly described. He also stated that he had seen similar galls “on the Post Oak at Asheville, N.C.” Consequently, the type series must include the two adult female specimens, both labelled as “type 2866” (deposited in USNM and ANSP), plus the gall specimens that Ashmead saw from Asheville, and the gall specimens from Washington that Osten-Sacken used for his description. The USNM has several collections of galls, identified as Callirhytis vaccinii and matching the description, and collected on “Q. obtusiloba”, some from Florida, and others card-mounted without further data but labelled as “type 2866” (Fig. 2A); the latter may very well represent the Asheville specimens, but we cannot assume this since the type labels were undoubtedly later additions, and we thus do not consider them to be syntypes. Further galls in the USNM, also labelled as Callirhytis vaccinii, were collected by Ashmead in Florida, but on “Q. minor”, and so cannot be syntypes (although they have erroneously been labelled as cotypes, Fig. 2B). To add to the confusion, there are five galls in ANSP labelled as “type” of Acraspis vaccinii in a similar style to some of the USNM galls, but collected in Florida on “Q. obtusiloba”, and so also not syntypes. Unfortunately, the syntype galls are thus presumed to be lost, misplaced or unidentifiable as such. We hereby formally designate the USNM type 2866 (USNMENT802403) as the lectotype of Acraspis vaccinii Ashmead, 1887 (Fig. 1), and the specimen (also labelled as a type, number 2866) deposited in ANSP as a paralectotype. This fixes the name as applicable to the adult only.

The galls of Andricus lustrans (? = "Callirhytis vaccinii" galls) are similar to those of a recently described new species, Andricus chapmanii Melika & Abrahamson, 2021 (Melika et al. 2021), and also to the galls of Andricus vacciniiformis (Beutenmüller, 1913) and Andricus robustus Weld, 1926. In fact, Beutenmüller (1918) mentioned that the mature galls of A. lustrans resembled those of A. vacciniiformis, and Weld (1926) wrote that the gall of A. robustus had previously been described in connection with the adult of A. vacciniiformis, which must then have come from a gall of a different sort accidentally included in the breeding cage. So, what are the "Callirhytis vaccinii" galls (Fig. 2)? The oak host of A. lustrans is unknown, according to the original description, but the galls of A. impositus (junior synonym of A. lustrans) occur on Quercus stellata (as Q. minor (Marsh.) Sarg.), as do the galls of A. vacciniiformis and A. robustus, while A. chapmanii occurs on Q. chapmanii. Osten-Sacken's (1862) galls, and the others mentioned in Ashmead (1897), occurred on Quercus stellata (as Q. obtusiloba) as shown in the labels visible in Fig. 2A, thus those galls could belong to A. lustrans, A. vacciniiformis or A. robustus. The gall of A. lustrans is unknown according to the original description, but has recently been photographed (Zhang et al. 2022). According to the descriptions of these galls, the shape is globular with a nipple at the apex, while those of A. chapmanii are truncate at the apex and depressed centrally; Beutenmüller (1913) mentioned that A. vacciniiformis galls are similar to the huckleberry fruit or to Celtis occidentalis L. fruit, but these fruits have different shapes; huckleberry fruit is truncated distally and depressed centrally and C. occidentalis has a pointed fruit.

To this point, the identity of the huckleberry-flower-like galls (truncated distally and depressed centrally) from Osten-Sacken (1862), erroneously associated with the adults used by Ashmead (1887) in his description of Acraspis vaccinii (Fig. 2), is uncertain. Since there are no adult samples reared from Osten-Sacken (1862) galls, we cannot associate those galls with any of the species mentioned. We therefore designate Callirhytis vaccinii Burks, 1979 as a species incertae sedis.

Examining the adults, we found important differences (Table 1). Adults of A. vacciniiformis have all metasomal segments pubescent (Fig. 3D), while in A. lustrans, A. impositus and A. robustus the pubescence is restricted to the second metasomal segment only (Fig. 3A–C); which may be the reason why both Weld (1926: 81) and Kinsey (1922: 17) mentioned that the "vacciniiformis" gall was incorrectly associated. Additionally, Kinsey (1922) affirmed that "verifactor" galls are undoubtedly "vacciniiformis" galls, and described the former as a variety of A. dimorphus (both are clustered leaf galls), even though both the adults and the galls of A. dimorphus (spherical galls) and A. dimorphus var. verifactor (urn-shaped galls) are different. Also, the synonymy of A. lustrans and A. impositus is doubtful because the length of the ventral spine of the hypopygium is different (Fig. 3A, B). Andricus dimorphus var. verifactor has the metasomal terga micropunctate, similar to A. chapmanii, so it is not a synonym of A. lustrans. Finally, A. lustrans has simple tarsal claws (type material examined), while in A. impositus and A. robustus they are toothed. Concerning the tarsal claws, A. impositus is a valid species, and not a synonym of A. lustrans: Andricus impositus Beutenmüller, 1918 status revalidated. Regarding the metasomal sculpture, A. dimorphus var. verifactor (with micropunctures on metasoma) is a valid species, not a synonym of A. lustrans (with smooth metasoma): Andricus verifactor Kinsey, 1922, stat. nov.

[unnamed]

Quercus obtusiloba. Post oak.

Clusters of small, somewhat bell-shaped, petiolate, greenish galls on the under side of the leaves, along the midrib.

Their shape may be compared to that of the flowers of Vaccinium. They are attenuated at the basis into a short petiole, fastened to the midrib of the leaf; the opposite end is truncated the truncature being excavated; the length, from the foot of the petiole to the truncated end, is from 0.12 to 0.15 inch. They grow in numbers, sometimes of ten or more together, so that six, for instance, form a row on one side of the midrib and four or five on the opposite. When found by me on the tree in October, 1861, these galls were pale green; the dry specimens are brownish. Inside of each was a small whitish larva, probably of a Cynips.

Callirhytis lustrans

Quercus breviloba, stellata
Leaf galls, detachable
Midrib cluster on under side of leaf in fall, each with a short stalk, end truncate and depressed. Fig 203

[Photo caption]
On Q stellata. Also on Q breviloba. Galls from Q breviloba gave adults the second and third springs in April. There is a similar gall on Q margarettae and on Q chapmanii which has never been reared.

Zopheroteras vaccinii

Quercus stellata
Leaf galls, detachable
Galls shaped like those of Callirhytis lustrans, Fig 203, in numbers in rows on either side of the midrib in the fall. Turn black in drying. Entered from lit.

[Presumed synonyms]
"like Callirhytis lustrans"

Quercus margaretta
Leaf galls, detachable
Midrib cluster like Callirhytis lustrans Fig 203

Zopheroteras, gen. nov.

To this genus belongs Acraspis vaccinii, Ashm

Andricus lustrans sp. nov.

Habitat.--Austin, TX, two females. The gall and male are not known.

Andricus lustrans Beutenmüller 1913, comb. rev.

Zopheroteras vaccinii Burks, 1979.
Callirhytis lustrans Weld, 1926.
Andricus dimorphus verifactor, Kinsey, 1922.
Andricus impositus, Beutenmüller, 1918.
Acraspis vaccinii (erroneously associated with gall only) Ashmead, 1887.

The gall of A. lustrans was first described by itself (without the larva or adult wasp) from Quercus stellata Wangenh. (Osten Sacken, 1862). As this name based on gall alone was established before 1931, it is considered valid according to ICZN article 23.3.2. Ashmead described a new wingless wasp and erroneously associated it with the gall Osten Sacken had described as Acraspis vaccinii Ashmead, 1887 (later transferred to Zopheroteras vaccinii by Beutenmüller in 1909a), while reprinting Osten Sacken’s description of the gall (Ashmead 1887).

In 1913 Beutenmüller described the wasp (Fig. 19–21) without the gall as Andricus lustrans Beutenmüller, 1913, and the same species with its gall a few years later which he named Andricus impositus Beutenmüller, 1918. He commented that the gall of A. impositus is similar to Z. vaccinii but the wasp did not match (Beutenmüller, 1918). Kinsey also separately described this species under the name Andricus dimorphus var. verifactor Kinsey, 1922, reared from Texas, Oklahoma, and Louisiana. In 1926, Weld concluded that A. impositus and A. dimorphus var. verifactor are the junior synonyms of A. lustrans, and transferred the species to Callirhytis (Weld, 1926). Most recently, the species was then erroneously synonymized with Z. vaccinii by Burks (1979) based on Ashmead’s error. The senior author examined the holotype specimen and freshly collected materials (Figs. 19–22), reinstating the name A. lustrans as the species lacks the diagnostic characteristics of Callirhytis. In the Nearctic Cynipini phylogeny by Ward et al. (2022), A. lustrans was recovered as the sister group to an undescribed “pentagonal cluster” gall, both of which are related to Andricus pisiformis Beutenmüller, 1911 and Andricus quercusstrobilanus (Osten Sacken, 1862). A similar-looking gall was recently described as Andricus chapmanii Melika & Abrahamson, 2021, but the adults of A. lustrans can be easily separated using characters such as the incomplete notaulus (Fig. 21), and metasomal tergites smooth (Fig. 19) (Melika et al. 2021a).

There is a large series of over 100 specimens collected from Bronx Park in NY that are identified as A. lustrans (identified as A. impositus) collected by Beutenmüller (1918) at NMNH, which he stated as common in the region but is becoming urbanized. There are no current records of this species on iNaturalist outside of TX, which could suggest a reduction in their distribution, despite Q. stellata being found across eastern US. Additional host records include Quercus sinuata var. breviloba (Torr.) C.H.Mull. (Weld 1959).

Callirhytis lustrans

Andricus lustrans
Andricus impositus
Andricus dimorphus verifactor
Acraspis vaccinii (gall only)

Lustrans was described from two adults captured at Austin, Texas, gall and host unknown. One of these specimens was given in 1921 to the writer, who recognized its close relation to impositus. Lustrans is described as without a median groove, but this specimen in certain positions shows a faint median line, while the groove in some of the many available parataypes of impositus is fully as faintly defined. The writer is unable to separate paratypes of verifactor from lustrans. The gall of this species was first described by Osten Sacken in 1862, but Ashmead was evidently in error in thinking he had reared it in 1887, associating the wingless fly he reared with the wrong gall. These galls occur as midrib clusters on under side of leaves of Quercus stellata in the fall, dropping when mature. When fresh the individual galls are shaped like huckleberry flowers, somewhat cylindrical with the end distinctly truncate and depressed, but during the winter on the ground they become globular except for a short pedicel, and the depressed end becomes a flattened circular scar at apex with a slightly raised rim, and the greenish or reddish color changes to brown.

Beutenmueller sent the writer galls from New York City which contained pupae on November 1 and adults on November 25 (age of galls unknown). The writer collected galls at Poplar Bluff and Ironton, Mo.; Wharton, Trinity, Arlington, and Boerne, Tex.; Hugo, Okla. At Hugo they were just starting to develop on July 25. Galls collected in October, 1917, at Trinity, Tex., gave two adults May 18, 1919. In galls collected at Ironton in fall of 1917 pupae were found in October, 1918, and in March, 1919, flies emerging before May 12, 1919. S. A. Rohwer collected galls at Ironton in October, 1918, and reared adults April 9-16, 1919, and a few more were found dead in cage May 12, 1920 (Hopkins U. S. No. 10777J). A precisely similar gall on the shin oak, Q. breviloba., was seen at Austin and Boerne, Tex., and may prove to be that of this species.