Discothyrea maia 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 : 55-56

Discothyrea maia Hita Garcia & Lieberman sp. n.

( Figs. 4L , 6L , 7L , 8L , 9L , 10L , 11L , 12L , 13E , 14L , 41 ,

42 ; Supp Video S12 [online only])

Type Material

Holotype, pinned worker, ZIMBABWE, Chishawasha , [−17.883, 31.227], 1535 m, I.1981 (A. Watsham) ( BMNH: CASENT0790541 ).

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 (CASENT0790541) 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 12).

Diagnosis

The following character combination distinguishes D. maia from the remainder of the complex: abdominal sternite 3 not rectangular Model 12. 3D surface model of D. maia sp. n. holotype (CASENT0790541). An interactive version of this model is available in the HTML version of this article online and at https://sketchfab.com/3d-models/a26ae6a2819a4473a6b 83152e2e82dff.

in profile, ventral margin rounded; mesosoma somewhat slender but not especially gracile (LMI 53; DMI2 81), dorsally convex in profile; propodeum denticulate denticles well-developed, propodeal declivity strongly concave; erect pilosity absent from mesosoma and abdominal terga; eyes absent; frontal lamella with elliptical basal fenestra.

Worker Measurements and Indices (n = 1)

EL 0.00; HL 0.50; SL 0.29; PH 0.26; PW 0.29; PrH 0.29; DML 0.36; WL 0.49; HFL 0.32; PeL 0.07; PeW 0.20; PeH 0.25; LT3 0.28; LT4 0.27; OI 0; CI 78; SI 58; LMI 53; DMI 59; DMI2 81; ASI 98; HFI 65; DPeI 286; LPeI 357.

Worker Description

Head somewhat elongate (CI 78); posterior head margin straight to weakly concave; posterodorsal corners of head rounded; in frontal view, sides of head weakly conexl anterolateral corners of gena well-defined; eyes absent; frontal lamella low and lobate in profile, with elliptical basal fenestra; medial clypeus narrow, anteriomedially projecting, lateral clypeus very weakly convex apically, lateral clypeus broadly curving between antennal sockets and anterolateral corners of head, entire clypeal margin bearing very short curved setae. Antenna with moderately long scape (SI 58), scape moderately incrassate, gently bent; pedicel subcylindrical, scarcely longer than broad; true antennomere count nine; apparent antennomere count 8–9, flagellomeres basad apical club highly compressed, taken together slightly shorter than apical club. Ventral head with well-developed, sinuate preoccipital ridge, with very short, triangular anteromedial carina; medial region of hypostoma rounded-triangular, arms slightly narrowed, somewhat spatulate apicolaterally; palpal formula not examined. Mandible edentate except for small prebasal angle; basal angle squared; ectal face with carina running from prebasal angle to apex, confluent with masticatory margin for entire length except laterad prebasal angle.

Mesosoma slender, gently convex in profile, pronotum somewhat higher than than propodeum; in dorsal view mesosoma elongate (DMI 59; DMI2 81), pronotum slightly wider than propodeum; pronotal humeri rounded; posterior propodeal margin strongly concave; posterodorsal corners of propodeum denticulate, denticles well-developed, dorsoventrally flattened, weakly diverging posterolaterally; declivitous face of propodeum distinctly concave in profile and oblique posterior view; propodeal spiracle relatively large, circular, directed posterodorsally; propodeal lobes welldeveloped, lobate.

Legs moderately long (HFI 65) and very slender; mesotibia without apicoventral spur or seta; mesobasitarsus fairly long, slightly longer than tarsomeres II–IV taken together.

Petiolar node strongly attenuated dorsally, about 3.6 times higher than long (LPeI 357); in profile anterior face of node sloping posteroventrally; in dorsal view, petiole subrectangular, about 2.9 times wider than long (DPeI 286), sides slightly convex; in anterior view, petiolar outline pentagonal, edges well-defined, dorsolateral angles rounded; in oblique anterodorsal view, anterior face flat; subpetiolar process fairly long, lobate, apex rounded.

Abdominal segment 3 elongate-campaniform, anteriorly prolonged slightly over anterior sternal margin, widest posteriorly; sternite in profile somewhat truncate; AS 3 with well-defined median ridge broadening to indistinct lobe posteriorly, reaching prora anteriorly; prora carinulate, concave; AT3 approximately as long as AT4; successive abdominal segments short, telescopic, concealed.

Sculpture on head, petiolar node, and abdominal segment 3 foveolate-reticulate, foveolae larger on lateral head surfaces, replaced by very fine rugulae anteromedially around frontal lamella; ventral head surface punctate to punctulate, mostly smooth medially except for small punctures arond subgenal sulcus; frontal lamella and clypeus rough, granulose to weakly rugulose; mandible with very small punctulae; dorsal mesosoma densely punctate-reticulate; punctae on lateral mesosoma sparser, sculpture more predominantly rugulose to reticulate; declivitous face of propodeum finely reticulate, reticulum most prominent ventrally; petiolar sternite densely punctate; abdominal tergite 4 conspicuously smoother than AT3, with very, shallow punctulae, becoming more strongly punctate posteriorly.

Setation on head dilute, short appressed pubescence; scape with slightly longer but tightly appressed pubescence; mesosoma and AT3 with very short, dilute, fine appressed pubesence, mostly restricted to dorsal surfaces of mesosoma; AT4 with longer, more conspicuous pubescence; successive abdominal segments with relatively short decumbent to erect setae, longer on terminal segments; legs with relatively long but tightly appressed pubescence, similar to scape; ectal face of mandible with fairly long, distinctly spaced, curved subdecubent setae; masticatory margin of mandible with row of straight, stout setae.

Color uniformly dull yellowish, appendages slightly lighter and more clear.

Etymology

In Greek mythology, Maia was a nymph of the seven Pleiades, mainland-dwelling sisters to the insular Kalypso; the new species is named for its morphological affinity to D. kalypso . In addition, maia in Greek means ‘midwife’, which is considered appropriate for an eusocial insect with an all-female working caste. The species epithet is to be treated as an appositive noun.

Distribution and Biology

At present, known only from the type locality in Zimbabwe ( Fig. 4L ). Unfortunately, no ecological information is provided on the collection label, but it may originate from savanna woodland.

Comments

Discothyrea maia is morphologically distinct from all mainland species of the traegaordhi complex except D. michelae , but the latter species is easily distinguished based on its standing pilosity, squared third abdominal tergite, and bilobed petiolar node, as well as by the form of the medial clypeus which is broad and transverse in D. michelae and anteriorly prolonged in D. maia . Presently, the only other member of the complex known from Zimbabwe is D. gaia , but both are unlikely to be confused due to noticeable differences in body size, overall shape, and pilosity.

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. 13. Diagnostic plate showing still images from surface volume renderings of mesotibiae and mesotarsi with mesotibial apicoventral spur, if present, colorized in green. (A) D. gaia, (B) D. poweri, (C) D. traegaordhi, (D) D. dryad, (E) D. maia, (F) D. wakanda.

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. 41. Stacked digital color images of D. maia sp. n. holotype (CASENT0790541). (A) Body in profile, (B) body in dorsal view, (C) head in full-face view.

Fig. 42. Still images from shaded surface display volume renderings of D. maia sp. n. holotype (CASENT0790541) 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.