Discothyrea gryphon Hita Garcia & Lieberman, 2019

Hita-Garcia, Francisco, Lieberman, Ziv, Audisio, Tracy L., Liu, Cong & Economo, Evan P., 2019, Revision of the Highly Specialized Ant Genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with X-Ray Microtomography and 3 D Cybertaxonomy, Insect Systematics and Diversity 5, pp. 1-84 : 45-48

Discothyrea gryphon Hita Garcia & Lieberman sp. n.

( Figs. 4I , 6I , 7I , 8I , 9I , 10I , 11I , 12I , 14I , 15I , 35 , 36 ;

Supp Video S9 [online only])

Type Material

HOLOTYPE, pinned worker, RWANDA, Kayove , [-1.876, 29.357], 2100 m, collection code ANTC37492, 12.VIII.1973 (P. Werner)

( BMNH: CASENT0790103). PARATYPES, two pinned workers with same data as holotype ( BMNH: CASENT0790104 ; SAMC: CASENT0247366 ); and two workers from RWANDA, Kayove , [-1.876, 29.357], 2100 m, collection code ANTC42122, 23.IV.1973 (P.Werner) ( CASC: CASENT0247367 ; MHNG: CASENT0247368 ) .

Cybertype. Volumetric raw data (in DICOM format), 3D rotation video, still images of surface volume rendering, and 3D surface (in PLY format) of the physical holotype (CASENT0790103) in addition to stacked digital color images illustrating head in full-face view, profile and dorsal views of the body.The data are deposited at Dryad (Hita Garcia et al. 2019, http://doi.org/10.5061/dryad.3qm4183) and can be freely accessed as virtual representation of the type. In addition to the cybertype data at Dryad, we also provide a freely accessible 3D surface model of the holotype at Sketchfab (Model 9).

Nontype Material

TANZANIA: Mkomazi Game Reserve , Maji Kununua, −3.8833, 37.81667, 1600 m, montane forest, 7.XII.1995 (H.G. Robertson) .

Diagnosis

The following character combination distinguishes D. gryphon from the remainder of the complex: mandible with square apical tooth and subapical denticle; subquadrate head with anterolateral corner of gena sharply defined, nearly denticulate; anterior clypeal margin with long erect setae; mesosomal outline weakly convex; propodeum without strong angles or denticles; mesotibia without apicoventral spur; AT4 about 1.1 times longer than AT3 (ASI 108– 113); erect pilosity abundant on mesosoma and abdominal terga.

Worker Measurements and Indices (n = 6)

EL 0.00–0.02; HL 0.51–0.53; HW 0.44–0.48; SL 0.30–0.32; PH 0.27–0.29; PW 0.30–0.33; DML 0.36–0.39; PrH 0.31–0.35; WL 0.56–0.58; HFL 0.29–0.31; PeL 0.08–0.11; PeW 0.20–0.22; PeH 0.20–0.23; LT3 0.30–0.33; LT4 0.33–0.36; OI 0–4; CI 87–92; SI 59–62; LMI 47–51; DMI 54–57; DMI2 82–86; ASI 108–113; HFI 52–54; DPeI 192–250; LPeI 200–275.

Worker Description

Head very broad (CI 87–92); posterior head margin straight, posterodorsal corners of head rounded; in frontal view sides of head slightly convex; head appearing subquadrate posterad antennal sockets; eyes absent or minute (OI 0–4), an asymmetrical pigmented spot, situated about one-third of the way between anterolateral corner of gena and posterior head margin; when present, eyes not visible in frontal view; anterolateral corner of gena sharply squared, appearing denticulate/dentate, somewhat projecting laterally; frontal lamella short and dentate in profile, apex acute; lamella translucent across entire disc, slightly more so basally but without distinct fenestra; medial clypeus broad, emarginate medially between antennae, lateral clypeus conspicuously narrowed, curving broadly between antennal sockets and anterolateral corners of head, entire clypeal margin bearing row of long erect setae. Antenna with moderately long scape (SI 59–62), scape moderately incrassate, gently bent; pedicel subcylindrical, longer than broad; true antennomere count six; apparent antennomere count six to eight, flagellomeres basad apical club highly compressed, taken together only about as long as apical club. Ventral head with poorly developed postoccipital ridge with very short but broad anteromedian carina; median region of hypostoma triangular, arms strongly narrowed and very weakly spatulate; palpal formula not examined. Mandible with squared apical tooth subtended by pointed preapical denticle; small prebasal angle present; basal angle rounded to somewhat truncate; ectal face with longitudinal carina confluent with masticatory margin for much of its length, leaving narrow strip of depressed region including prebasal denticle.

Mesosoma in profile robust, dorsally feebly convex, sloping posteroventrally, pronotum distincly higher than propodeum; in dorsal view mesosoma moderately thick (DMI 54–57; DMI2 82–86) and narrowed posteriorly, pronotum wider than propodeum; posterior propodeal margin very weakly concave; posterodorsal corners of propodeum rounded, without teeth or angles; declivitous face of propodeum shallowly but clearly concave in profile and oblique posterior view; propodeal spiracle small and inconspicuous, directed posterolaterally; propodeal lobes short, truncate.

Legs short (HFI 52–54) and rather slender; mesotibia without apicoventral spur.

Petiolar node not strongly attenuated dorsally, rather robust in profile, about 2.0 to 2.8 times higher than broad (LPeI 200–275); in profile anterior face of node convex, apex blunt to rounded, posterior face convex; in dorsal view petiole rectangular, sides subparallel, about 1.9 to 2.5 times broader than long (DPeI 192–250); in anterior view, petiolar outline clearly pentagonal, edges well-defined, angles slightly rounded, apex somewhat broadly peaked; in oblique anterior view anterior face flat; in ventral view subrectangular to weakly campaniform, sides slightly divergent posteriorly to weakly convex; subpetiolar process large, lobate-triangular, apex rounded, Model 9. 3D surface model of D. gryphon sp. n. holotype (CASENT0790103). An interactive version of this model is available in the HTML version of this article online and at https://sketchfab.com/3d-models/b89fada99bce4f169c7b 7d55f977326a.

bearing numerous long, straight, white setae; petiolar spiracles large, round to slightly elliptical in ventral view.

Abdominal segment 3 asymmetrically campaniform, tergite prolonged anteriorly beyond anterior margin of sternite and widest point just anterad end of segment; AS 3 evenly rounded in profile, deepest point at about the longitudinal midline in profile, with thick median ridge; AS 3 without carinate prora, but still with anterior face distinctly depressed and anterior margin of ventral face weakly concave in ventral view; AT4 about 1.1 times longer than AT3 (ASI 108–113); AT4 evenly rounded hemidemispherical; AS 4 with very well-developed anterior lip, overlapping nearly the entire width of AS 3, anterior margin very weakly concave in ventral view; successive abdominal segments short, telescopic, often concealed.

Sculpture on head foveolate-reticulate to areolate, foveolae smaller on front of head; mandible rather roughly sculptured with dense piligerous punctae; frontal lamella and medial clypeus distinctly punctate; mesosoma, petiole, and abdominal segment 3 foveolate-reticulate, foveolae smaller and more regular on dorsal than lateral mesosoma, with rugulae present between foveolae on lateral mesosoma, especially posteriorly; declivitous face of propodeum with narrow transverse rugulae and sometimes punctae; AT4 quite smooth and shiny despite numerous minute piligerous punctulae.

Setation consisting of distinct, erect, white pilosity on front of head, mesosomal, petiolar and abdominal dorsa, generally becoming longer and denser with each succesive tagma in the posterior direction; lateral mesosoma with mostly appressed pubescence; sides of abdominal segments 3 and 4, petiolar sternite, and abdominal sternite 3 also bearing long erect setae in addition to underlayer of appressed pubescence; abdominal segments five through seven with similar pilosity to AT4, setae not noticeably longer or more curved; scape and legs with long, dense pubescence, mostly appressed to decumbent, with scattered erect setae; ectal face of mandible with abundant, long, curved, erect to suberect setae; setation of masticatory margin undetermined.

Color uniformly dull testaceous-yellow to light brown.

Etymology

The gryphon of mythology was a legendary creature with a body composed of different animals. Discothyrea gryphon is named like for its strange combination of characters, which are approximated only by the aberrant D. chimera . The archaic spelling gryphon is used in preference to the Latinate griffin as wordplay on the Greek root grypos, meaning hooked, in reference to the recurved abdomen of Discothyrea . The specific epithet is given as an appositive noun.

Distribution and Biology

At present, known only from the type locality in Kayove in Rwanda and Mkomazi in Tanzania ( Fig. 4I ). Both localities are montane forest at elevations from 1600 to 2100 m. Discothyrea gryphon lives in leaf litter.

Comments

Discothyrea gryphon is easily recognizable on the basis of a combination of highly species-specific character states. The presence of a subapical tooth, dense standing pilosity, subquadrate head shape with sharply defined genal corners, and the row of long, straight setae on the anterior clypeal margin rapidly discriminate it from the remainder of the complex. As noted above, the similarity of D. gryphon and D. chimera , in the characters of the head and general habitus, suggest that they may constitute a natural group.

Variation

All examined specimens are consistent in virtually all characters. However, the development of the subapical mandibular denticle ranges from an indistinct angle to a relatively distinct, small denticle. This variation may be due to the denticle being worn down with age.

Figures

Fig. 4. Maps showing the known distribution ranges of Afrotropical Discothyrea species.

Fig. 6. Diagnostic plate showing still images from surface volume renderings of the head in full-face view (the remainder of the body virtually removed). All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation.Specimen codes are given inTable 1.

Fig. 7. Diagnostic plate showing still images from surface volume renderings of the head in profile (the remainder of the body virtually removed).All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation. Specimen codes are given inTable 1.

Fig. 8. Diagnostic plate showing still images from surface volume renderings of the right mandible in dorsal view (the remainder of the body virtually removed).All Afrotropical species are shown,species names are embedded in each particular image for better comparison and orientation.Specimen codes are given inTable 1.

Fig. 9. Diagnostic plate showing still images from surface volume renderings of the mesosoma in profile (the remainder of the body virtually removed). All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation.Specimen codes are given inTable 1.

Fig. 10. Diagnostic plate showing still images from surface volume renderings of the body in dorsal view with focus on mesosoma.All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation. Specimen codes are given inTable 1.

Fig. 11. Diagnostic plate showing still images from surface volume renderings of the posterior propodeum in posterior view (the remainder of the body virtually removed). All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation. Specimen codes are given inTable 1.

Fig. 12. Diagnostic plate showing still images from surface volume renderings of the petiole and gaster in profile (the remainder of the body virtually removed).All Afrotropical species are shown, species names are embedded in each particular image for better comparison and orientation.Specimen codes are given inTable 1.

Fig. 14. Diagnostic plate showing differences in body pilosity. (A) D. mixta (CASENT0235473),(B) D. oculata (CASENT0235467),(C) D. aisnetu (CASENT0235475), (D) D.athene (CASENT0235476),(E) D.chimera (CASENT0235471),(F) D.damato (CASENT0247362),(G) D.dryad (CASENT0247371),(H) D.gaia (CASENT0247040), (I) D. gryphon (CASENT0247367), (J) D. hawkesi (CASENT0235470), (K) D. kalypso (CASENT0235468), (L) D. maia (CASENT0790541), (M) D. michelae (CASENT0235469), (N) D. patrizii (CASENT0235472), (O) D. penthos (CASENT0247383), (P) D. poweri (SAM-ENT-0011509), (Q) D. schulzei (CASENT0247370), (R) D. traegaordhi (CASENT0790122), (S) D. venus (CASENT0247017), (T) D. wakanda (CASENT0790326).With the exception of F, L, R,T, all other images are from https://www.antweb.org—photographers Michele Esposito and Will Ericson.

Fig. 15. Antennal anatomy showing flagellar fusion in Discothyrea. (A) D. mixta (CASENT0285473)—light microscopy, (B) D. traegaordhi (CASENT0790122) —light microscopy, (C) D. traegaordhi (CASENT0790122)—equivalent view to 15B but performed with surface volume rendering, (D) Zasphinctus sarowiwai Hita Garcia, 2017 (CASENT0764654)—sagittal section of surface volume rendering, (E) D. traegaordhi (CASENT0790122)—sagittal section of surface volume rendering, (F) D. mixta (CASENT0790542)—surface volume rendering showing each antennomere in different color, (G) D. mixta (CASENT0790542)—equivalent view to 15F but sagittal section, (H) D. dryad (CASENT0247374)—sagittal section of surface volume rendering showing each antennomere in different color, (I) D. gryphon (CASENT0790103),sagittal section of surface volume rendering showing each antennomere in different color.

Fig. 35. Stacked digital color images of D. gryphon sp. n. paratype (CASENT0247367—from https://www.antweb.org, photographerWill Ericson). (A) body in profile, (B) body in dorsal view, (C) head in full-face view.

Fig. 36. Still images from shaded surface display volume renderings of D. gryphon sp. n. holotype (CASENT0790103) showing virtually segmented body parts. (A) Body in dorsal view, (B) body in profile, (C) head in full-face view, (D) head in dorsal view, (E) head in anterodorsal view, (F) head in anterior view, (G) head in profile, (H) head in ventral view, (I) posterior propodeum in posterior view, (J) petiole in profile, (K) petiole and gaster in profile, (L) petiole in dorsal view, (M) petiole in anterior view, (N) petiole oblique anterior view, (O) gaster in dorsal view, (P) petiole in ventral view, (Q) abdominal sternite 3 in ventral view, (R) mesotibia and mesotarsus in anterior view.