Disholcaspis erugomamma, Cooke-Mcewen & Gates, 2020

Cooke-Mcewen, Crystal & Gates, Michael, 2020, Contributions to Disholcaspis Dalla Torre And Kieffer (Hymenoptera: Cynipidae: Cynipini), Zootaxa 4859 (3), pp. 355-382: 370-376

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Disholcaspis erugomamma


Disholcaspis erugomamma  Cooke-McEwen, sp. nov.

Diagnosis: Special emphasis was placed on comparing D. erugomamma  with other species that have been found on the same host plant, those that could be collected in Texas, and species that had similar galls. The only other species of Disholcaspis  documented on Q. havardii Rydb.  is D. spissa ( Weld 1957)  . Disholcaspis erugomamma  differs from D. spissa  in that it has the scape + pedicel shorter than F1 rather than slightly longer, the notauli black instead of brown, mesoscutellum mostly black instead of mostly brown, and the extended portion of the hypopygial spine 1.3–1.9x as long as wide instead of 2.3x as long as wide. Disholcaspis erugomamma  differs from most of the Texas inhabiting species in that the head has black markings around the toruli, ocellar triangle, and malar margins; antennae are black; notauli black; mesoscutellum mostly dark brown to black; and metasoma mostly black. Lastly, most species in Texas differ from D. erugomamma  in their gall morphologies. Disholcaspis fungiformis  and D. cinerosa Bassett  are both known from hosts in a different section of host plant, section Virentes, and therefore could not be the same species as the newly found species on a section Quercus  host. The type for D. spongiosa  could not be found for comparison so general collection specimens were used. Disholcaspis erugomamma  is morphologically most similar to D. quercusmamma  , D. quercusglobulus  , D. bassetti (Gillette)  , D. globosa Weld  , D. persimilis (Ashmead)  , D. colorado (Gillette)  , and D. lacuna Weld. However  , it should be noted that this species was determined in this study to be genetically distant from D. quercusmamma  and D. quercusglobulus  . The Mexican species D. laetae Kinsey  , D. mexicana  (Beutenmüller), D. pallens Kinsey  , and D. pulla Kinsey  were also compared but they differed greatly in coloration and/or gall morphology. The diagnostic combination of traits for D. erugomamma  is antennae black with some specimens having first 4 segments dark brown apically; head trapezoidal in anterior view; a black patch at the upper corner of the gena; notauli black; mesoscutellum black at least along anterior and lateral margins; metasoma mostly dark brown to black; extended portion of hypopygial spine 1.3–1.9x as long as wide; and galls 1.2–1.5cm smooth surfaced, rounded, and globular shaped galls with a short pointed nipple. For the examined types and other specimens representing the other Disholcaspis  species see Supplementary Table 1.

Asexual female ( Fig. 38–46View FIGURES 36–41View FIGURES 42–47): Total body length 3.9mm. Color. Antennae, area around and below toruli, clypeus, malar space margin, area around ocelli, patch at upper corner of gena, back of head black; rest of head brown to dark brown; mouth palps dark brown at base and fading to brown distally; mandibles brown medially and black along the margins; compound eyes and ocelli silver. Pronotum medially, along posterior margin, and along anteroventral margin black, remainder brown to dark brown; mesoscutum, with thick area around anterior parallel lines, parapsidal lines, and notauli black, rest of mesoscutum dark brown; scutellum black except posterior margin dark brown; mesopleural triangle, mesopleural margins, and patch extending diagonally across mesopleuron from mesopleural triangle black, remainder brown to dark brown; propodeum and metanotum black. Legs dark brown, coxae brown. Metasoma mostly black with dark brown in small patch laterally on the second tergum and along some tergite margins.

habitus, D. quercusmamma  , (52) sexual female anterior head, D. quercusmamma  , (53) sexual female wing, D. eldoradensis  .

Head ( Fig 38–40View FIGURES 36–41). Anteriorly 1.3–1.4x as broad as high, dorsally 0.38x as long as broad, coriaceous with lower face, malar space, and gena more finely coriaceous, coriaceous to finely rugose around ocellar triangle; near-trapezoidal in anterior view with ocelli raised; face with white setae throughout but more dense on lower face. Gena broadened behind compound eye in anterior view; lateral width of the gena 0.57x as wide as the compound eye height. Compound eye 0.50x as high as frontal head height; transfacial line 1.3x as long as compound eye height¸ diameter of torulus 1.1x distance between them; distance between torulus and compound eye margin 1.2x diameter of torulus; length of malar space 0.44x height of compound eye, without striae and sulcus; compound eyes nearly parallel. LOL 1.5x as long as the lateral ocellus; OOL 2.1x length of lateral ocellus; POL 1.5x as long as OOL and 3.1x as long as length of lateral ocellus. Clypeus trapezoidal with ventral margin longer than dorsal margin, 1.6x as broad as high, ventral margin convex; anterior tentorial pits present; clypeo-pleurostomal and epistomal sulcus distinct, deeply depressed, and smooth. Occiput rounded, setose, and without carina; postocciput smooth; postgena setose, otherwise smooth; height of occipital foramen 0.78x as long as postgenal bridge and 1.1x as long as broad; hypostomal sulci separated at oral foramen. Labial palpus 3-segmented, maxillary palpus 4-segmented. Antennae 14-segmented; pedicel as long as broad; antennal segment length ratio 24:11:39:36:30:28:22:19:13:11:11:9:8:13; placoid sensilla on F4–F12 conspicuous, absent on F1–F3.

Mesosoma ( Fig. 41–44View FIGURES 36–41View FIGURES 42–47). Laterally 1.2x as long as high. Pronotum with white setae, smooth laterally; impressed along propleuron. Propleuron setose and smooth. Mesoscutum delicately coriaceous except smooth between notauli, setose; 1.2x as wide as long. Notauli present in posterior 1/2 fading to coriaceous texture anteriorly, incomplete and converging posteriorly; anterior parallel distinct, extending 0.47x as long as mescutum length; parapsidal lines broad and smooth, extending just over 1/2 length of mesoscutum; median mesoscutal line absent. Mesoscutellum slightly broader than long, smooth and depressed along anterior margin, coriaceous otherwise, overhanging metanotum, with white setae, more setose on posterior half; scutellar foveae absent. Mesopleuron smooth, setosee throughout; mesopleural triangle densely setose and with transverse striations; acetabular carina only visible ventrally. Dorsoaxillar area setose; axillar carina with longitudinal striae; axillula densely setose; subaxillular bar smooth; metapleural sulcus reaching mesopleuron just over half its height. Metascutellum delicately rugose; metanotal trough smooth and with setae; ventral impressed rim smooth. Lateral propodeal carinae bent outward and broken, medial propodeal area smooth; lateral propodeal area setose; nucha short and rugose. Forewing extending beyond apex of metasoma; radial cell 3.5x as long as wide; M, Rs+M, and Cu1a visible; Rs curved, nearly reaching wing margin; areolet closed Rs+M reaching half way to M. Tarsal claws with basal lobe.

Metasoma ( Fig. 45–46View FIGURES 42–47). Length 0.83x as long as mesosoma and head. Second tergite 0.70x length of metasoma; tergite 2 with setae anteromedially to laterally, following 4 tergites without setae; all tergites smooth and shiny. Hypopygial spine ventrally tapering evenly to tip, extended portion 1.9x as long as broad basally, with subapical setae reaching beyond spine apex.

Variation. Some specimens have more black coloration on the upper face between the toruli and the ocelli; in a few specimens the basal 4 antennal segments are dark brown apically with remaining segments black; notauli in some specimens with a black patch along the medial margin; in a few specimens the mesoscutellum is dark brown medially as well as along the posterior margin. The variation in the various ocellar lengths compared to the lateral ocellus widest width is as follows: LOL 1.5–2.0x as long as the lateral ocellus; OOL 1.8–2.7x length of lateral ocellus; and POL 3.1–4.3x as long as length of lateral ocellus. There is variation in the ratios of the antennal segments but F1 is always longer than scape+pedicel and F2; radial cell 3.3–4.0x as long as wide; extended portion of the hypopygial spine 1.3–1.9x as long as wide. Radial cell 3.2–3.8x as long as wide.

Gall ( Fig. 47View FIGURES 42–47): Reddish brown, globular with a short, obtusely pointed nipple apically or few may lack the nipple entirely. Dispersed or more commonly tightly clustered and deforming around each other. Internally with dense, rather hard, corky texture; larval cell not free in galls examined. Gall is most similar to that of D. quercusmamma  , but the surface is wrinkled in that species and relatively smooth in D. erugomamma  . It is uncertain if the galls are nectar secreting, but the black sooty mold that is typical for mature nectar secreting galls was lacking. The galls were covered in dust when found but it is uncertain if that dust was a trait of the gall itself as opposed to its dusty arid environment near a road.

Type material: Holotype:first label“ USA:TX: Crane Co. East bound I-20frontage road, 31.650381, -102.745986 9.Nov.2013 C.Cooke ”, second label “Ex. Q. havardii, Emg.  25.Dec.2013, Assoc. gall USNMENT00961500”, and third label “USNMENT 00961981” (deposited in USNM)GoogleMaps  Paratypes (all deposited in USNM): first label for all specimens “ USA: TX: Crane Co. East bound I-20 frontage road, 31.650381, -102.745986 9.Nov.2013 C.Cooke ”; one specimen with second and third labels “Ex. Q. havardii, Emg.  25.Dec.2013, Assoc. gall USNMENT00961500” and “USNMENT00961260”; five specimens with second label “Ex. Q. havardii, Emg.  26.Dec.2013, Assoc. gall USNMENT00961973” and third labels “USNMENT00961825”, “USNMENT00961685”, “USNMENT00961485”, “USNMENT00961768”, and “USNMENT00961455”; one specimen with second and third labels “Ex. Q. havardii, Emg.  30.Dec.2013, Assoc. gall USNMENT00961863” and “USNMENT00961882”; one specimen with second and third labels “Ex. Q. havardii, Emg.  12.Jan.2013, Assoc. gall USNMENT00961846” and “USNMENT00961488”; one specimen with second and third labels “Ex. Q. havardii, Emg.  25.Dec.2013, Assoc. gall USNMENT00961262” and “USNMENT00961932”; one specimen with second and third labels “Ex. Q. havardii, Emg.  30.Dec.2013, Assoc. gall USNMENT00961959” and “USNMENT00961641”; and three specimens with second labels “ USN- MENT00961734 ”, “USNMENT00961798”, and “USNMENT00961984”GoogleMaps  .

Biology: Only the asexual generation is known at this time. All wasps reared for this study emerged toward the end of December or early January.

Etymology: Named for the gall morphology. From Latin, erugo meaning to free of wrinkles (noun in apposition) and mamma as a reference to the mammiform gall shape ( Brown 1956).

Distribution: Known only from the single collecting event in western Texas. Collecting site was revisited in spring 2020 and empty fall galls were present.

Host plant remarks: The host plant voucher is deposited at MARY and identified as Q. havardii  . It has a small range from northwestern Texas to New Mexico and Oklahoma, with disjunct populations in northern Arizona and southern Utah ( Nixon, 1997).


Smithsonian Institution, National Museum of Natural History