Trichagalma Mayr, 1907

Melika, George, Pujade-Villar, Juli, Abe, Yoshihisa, Tang, Chang-Ti, Nicholls, James, Wachi, Nakatada, Ide, Tatsuya, Yang, Man-Miao, Pénzes, Zsolt, Csóka, György & Stone, Graham N., 2010, 2470, Zootaxa 2470, pp. 1-79 : 9-11

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Trichagalma Mayr, 1907


Trichagalma Mayr, 1907 , stat. rev.

Figs 24–30; 36–42; 43–49.

Type species: Trichagalma serratae (Ashmead) . Designated by Mayr (1907) by monotypy, Trichagalma drouardi Mayr.

Taxonomic status. Monzen (1929) synonymized T. drouardi to Dryophanta serratae Ashmead and proposed a new name combination, Trichagalma serratae (Ashmead) . Abe (2006) synonymized Trichagalma to Neuroterus based on the closed lifecycle ( Masuda 1972; Usuba 1995) and described the adults of the sexual generation. The main diagnostic characters of Neuroterus given in Melika et al. (1999) and Melika & Abrahamson (2002) were used. However, in the current assessment of Cynipini groups, those diagnostic characters define not a genus but the Neuroterus Pseudoneuroterus Trichagalma complex of genera lacking or with an incomplete transscutal articulation. After reappraising these diagnostic characters, we re-establish the genus Trichagalma as in earlier treatments ( Pujade-Villar et al. 2004).

Diagnosis. Most closely related to Pseudoneuroterus ; however, can easily be distinguished by predominantly brown body colour, by very dense white setae on the head and mesosoma and also by notauli which are superficial but always present, complete or hardly traceable in the anterior 1/3, and by a transverse head, the broadest part of which is on the level of upper margin of compound eyes. Superficially resembles also Cerroneuroterus but differs by superficially impressed notauli, and a coriaceous or reticulate rugose mesoscutellum. In overall habitus, Trichagalma also closely resembles Western Palaearctic Aphelonyx , however, in Aphelonyx the transscutal articulation is distinct, the projecting part of the ventral spine of the hypopygium is long, needle-like, 4.5 – 5.0 times as long as broad, with few short white setae; the forewing always without dark smoky spots. More diagnostic characters are given in the generic key above.

Redescription. Asexual form. Body reddish brown; antenna black or dark brown, with black antennal sockets; head posteriorly, stripes along anteroadmedian and parapsidal signa, base of mesoscutellum (in some species), metascutellum, propodeum, mesopleural triangle, metapleuron black. Head and mesosoma with dense long white setae, obscuring sculpture of head and mesosoma; head trapezoid, broadest above transfacial line, broader than high in anterior view, gena distinctly broadened behind eye; height of compound eye 1.8 times as long as length of malar space; transfacial distance 1.5 times as long as height of eye; malar sulcus absent, only short weak striae radiating from clypeus that never reach eye margin. Antenna with 12 flagellomeres (sometimes indistinct suture indicates F13); F1 1.3 – 1.5 times as long as F2. Mesoscutum longer than broad, 1.5 times as long as mesoscutellum, delicately coriaceous, notauli very superficial, complete or very hardly traceable in anterior half or 1/3; median mesoscutal line absent, anteroadmedian and parapsidal signa broad, slightly raised, less pubescent. Mesoscutellum always longer than broad, with parallel sides, never emarginate laterally and posteriorly, never trapezoid, uniformly reticulate rugose or coriaceous; scutellar foveae absent, instead anterior transverse depression present which is nearly in same plane as mesoscutellum disk, with same sculpture on bottom, not or only very slightly deeper than disk. Metascutellum coriaceous, broader than height of metanotal trough. Propodeum bare, smooth, without lateral propodeal carinae. Forewing margin with long cilia, without or with smoky dark pigmented spots; radial cell 3.5 – 4.5 as long as broad. Tarsal claws simple, without basal lobe. Metasomal tergites 2 to 5 and 7 with white setae laterally; 2nd metasomal tergite dorsally occupying maximum 1/3 length of metasoma; prominent part of ventral spine of hypopygium very short, nearly as long as broad. Sexual form. Body black, antennae, palpi, tegulae and legs brownish yellow. Head and mesosoma almost smooth, without or with very few sparse white short setae. Head broader than mesosoma, vertex coriaceous, striae on malar space very weak, indistinct, incomplete, never reaching inner margin of eye. Antenna with 12 flagellomeres, F1 longest. Notauli absent; mesoscutellum reticulately rugose, with smooth central disk; propodeum uniformly very delicately sculptured, without lateral propodeal carinae. Forewing without smoky spots, margins with cilia. Tarsal claws simple, without basal lobe. Second metasomal tergite with few setae dorsolaterally; the prominent part of the ventral spine of the hypopygium slender, short, approximately 2.0 times as long as broad, subapical setae extend far beyond apex. Male differs from female by antenna which is with 13 flagellomeres, F1 incised and slightly swollened apically.

Biology and Distribution. Currently three species are known: T. serratae , T. acutissimae and T. formosana . For one species, T. serratae , alternating sexual and asexual generations are known ( Masuda 1972, Usuba 1995). Host oaks in Quercus subgen. Quercus section Cerris: Quercus acutissima Carruth. and Q. variabilis Blume.

Trichagalma serratae ( Ashmead, 1904) . The holotype female with three labels: “ Dryophanta serratae ♀ Ash ”, “48.”, “ ♀ Type No. 7142 U. S. N. M.”. The metasoma of the holotype is separated from the head and mesosoma. The right forewing and hindwing are mounted on a glass slide. The holotype specimen has no label on which the type locality and collection data must have been described. According to Ashmead (1904), the holotype was mounted on card-board with its gall, but the gall is not mounted at present. Ashmead (1904) mentioned that the type locality is Sapporo, Hokkaido, northern Japan and that the host plant is Q. serrata . After the original description, however, the galls induced by this gallwasp have been recorded from Q. acutissima and Q. variabilis alone, and both plant species are not distributed in Hokkaido ( Abe 2006). Descriptions of galls and details on the biology and lifecycle are provided by Abe (1992, 2006), and Yukawa & Masuda (1996). Known from Japan (Honshu, Shikoku and Kyushu), China and South Korea ( Abe 2006; Abe et al. 2007).

Trichagalma acutissimae ( Monzen, 1953) , new comb. Currently known only from Japan. Originally described as Aphelonyx acutissimae by Monzen (1953). There is only one female adult specimen of T. acutissimae in the K. Monzen Collection. However, it is possible that this gallwasp species description was based on more than one specimen, judging from the description of the localities ( Monzen 1954). According to the Recommendation 73 F (International Commission on Zoological Nomenclature 1999), the specimen labelled “Kunugihauratamafushi, 28/XI 1952, ♀, on campus, K. Monzen, Callirhitis [sic]” is hereby designated as the lectotype. “Kunugihauratamafushi” is a Japanese name of the gall induced by this gallwasp. “Kunugi” is a Japanese common name of Q. acutissima . “ha”, “ura” “tama” and “fushi” mean “leaf”, “underside”, “ball” and “gall” in Japanese, respectively. Dr. K. Monzen was a professor at Iwate University in 1952. The type locality, the campus of this university, is located in Morioka City, Iwate Prefecture, Japan. The head of the lectotype is lost. The gall is spherical, smooth, 5.0-7.0 mm in diameter, pale yellow, red or brownish-red with minute bark spots, monolocular, with larval chamber in the center, located on veins of both sides of the leaf of Q. acutissima and Q. variabilis ( Yukawa & Masuda 1996, picture C-094) ( Figs 48 – 49). Galls begin to appear in early June; pupation takes place in October, adult eclosion occurs in November, and adults emerge from their galls in late November to December ( Yukawa & Masuda 1996). In this species, notauli are superficial, incomplete in the anterior 1/3 of the mesoscutum; the head is trapezoid, strongly transverse in anterior view, with the broadest part at the upper margin of compound eyes; the mesoscutum, especially between notauli, with distinct micropunctures; the mesoscutellum uniformly rugose reticulate, not emarginate around – all these characters allow us to transfer this species to Trichagalma .

Comments. The presence of dark smoky pigmented spots on the forewing of Trichagalma serratae and T. formosana seems to be a specific and not a generic character. The same is true for nearctic Antron Kinsey and Atrusca Kinsey species , most of which have spots on the forewing, while some species lack them (e.g., Atrusca cava (Weld) , A. luminata Kinsey , Antron plumbeum (Weld)) .

In the phylogenetic reconstruction by Liljeblad et al. (2008), Trichagalma serratae appears in one clade with Pseudoneuroterus macropterus . DNA sequence analysis ( Fig. 2 in Rokas et al. 2003) also shows a distinct distance between Trichagalma serratae and ( Pseudoneuroterus macropterus + Neuroterus saliens (Kollar)) . Additional sequence data (J. Nicholls, unpublished data) suggest that Trichagalma serratae , together with the herein described T. formosana , forms a distinct, plesiomorphic lineage within the section Cerris galling genera.