Discothyrea damato 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 : 37-40

Discothyrea damato Hita Garcia & Lieberman sp. n.

( Figs. 4F , 6F , 7F , 8F , 9F , 10F , 11F , 12F , 14F , 29 , 30 ; Supp Video S6 [online only])

Type Material

HOLOTYPE, pinned worker, UGANDA, Western, Kabarole, Kibale National Park, Kanyawara Biological Station , 0.56437, 30.36059, 1510 m, rainforest, ex leaf litter, collection code FHG01047, 6.–16.VIII.2012 (F. Hita Garcia) ( BMNH: CASENT0247362 ) . Paratypes, seven pinned workers with same data as holotype Model 6. 3D surface model of D. damato sp. n. holotype (CASENT0247362). An interactive version of this model is available in the HTML version of this article online and at https://sketchfab. com/3d-models/970757df7eaf41088198 af1daccbd09c.

except for collection codes FHG01020, FHG01024, and FHG01039 ( CASC: CASENT764586; HLMD: HLMD-Hym-2396; MCZC: MCZ-ENT00593558; KSMA: CASENT0247019; MHNG: CASENT0764587; SAMC: CASENT0764588; ZFMK: CASENT0247363).

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 (CASENT0247362) in addition to stacked digital color images illustrating head in full-face view, profile and dorsal views of the body. The data is 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 6).

Nontype Material

DEMOCRATIC REPUBLIC OF CONGO: Kivu, Lubero Territory, Rte. Kimbulu, ruis. Kitagoha , [−0.05311, 29.22183], 1760 m, tamisage de terreau, IV.1954 (R. P. M. J. Celis) ; KENYA: Western Province, Kakamega Forest, Bunyala Forest Fragment, 0.37889, 34.69917, 1448 m, primary forest, 1.VIII.2008 (G. Fischer) ; RWANDA: Gisovu , [−2.25, 29.34], ca. 2200 m, 18.IV.1973 (P. Werner); Kamiranzovu, [−2.49, 29.15], 1900 m, I.1976 (P. Werner); Kayove, [−1.88, 29.36], 2100 m, 12.VIII.1973 (P. Werner) .

Diagnosis

The following character combination distinguishes D. damato from the remainder of the complex: masticatory margin of mandible edentate; frontal lamella with conspicuous, large, elliptical basal fenestra; anterolateral corner of gena not denticulate/dentate; eyes absent to tiny (OI 0–4); in dorsal view mesosoma conspicuously thick, robust and stocky (DMI 59–66; DMI2 95–102); in profile mesosoma not extremely convex and propodeum angulate to dentate; mesotibia without apicoventral spur; AT4 around 1.2 times longer than AT3 (ASI 117–128); abdominal sternite 3 without any projecting lobe; anterior clypeal margin without conspicuous row of long, straight setae; dorsal surfaces of mesosoma, petiole, and gaster without standing pilosity.

Worker Measurements and Indices (n = 15)

EL 0.00–0.02; HL 0.45–0.53; HW 0.37–0.45; SL 0.24–0.29; PH 0.22–0.28; PW 0.28–0.33; DML 0.28–0.35; PrH 0.26–0.37; WL 0.43–0.56; HFL 0.25–0.32; PeL 0.06–0.09; PeW 0.17–0.21; PeH 0.17–0.23; LT3 0.25–0.35; LT4 0.31–0.43; OI 0–4; CI 79–85; SI 51–62; LMI 48–53; DMI 59–66; DMI2 95–102; ASI 117–128; HFI 54–61; DPeI 233–286; LPeI 243–314.

Worker Description

Head subrectangular, longer than broad (CI 79–85), posterior head margin flat to gently convex, with very weak impression medially; posterodorsal corners of head quite broadly rounded; in frontal view, sides of head weakly convex; eyes absent or extremely minute (OI 0–4), if present, tiny, pigmented spot situated about one-third of way between anterolateral corner of gena and posterior head margin, usually not visible in frontal view; frontal lamella roundedtriangular in profile; lamella with very conspicuous, large, elliptical basal fenestra; medial clypeus convex, lateral clypeus strongly curving between antennal sockets and anterolateral corners of head, sides of medial clypeus nearly parallel laterad antennal sockets, bearing very short curved setae. Antenna with scape of short to intermediate length (SI 51–62), scape clearly incrassate, gently bent; pedicel subcylindrical, broader than long; true antennomere count nine; apparent antennomere count eight to eleven; flagellomeres basad apical club highly compressed, taken together shorter than apical club. Ventral head with narrow, roughly V-shaped postoccipital ridge without anteromedian carina; median region of hypostoma triangular, arms narrowed and slightly spatulate apicolaterally; palpal formula not examined.

Mandible edentate except for small, sharp prebasal denticle; basal angle rounded; ectal face with longitudinal carina nearly confluent with masticatory margin for almost its entire length, leaving very narrow depressed masticatory strip including prebasal denticle.

Mesosoma in profile moderately high and relatively flat, pronotum significantly lower than propodeum, propodeum strongly angulate to dentate, posterolaterally conspicuously concave; in dorsal view mesosoma conspicuously thick, robust and stocky (DMI 59–66; DMI2 95–102), strongly narrowed posteriorly, pronotum much wider than propodeum; pronotal humeri rounded; posterior propodeal margin distinctly concave; propodeal spiracle directed posterolaterally; propodeal lobes well developed, lobate.

Legs short to moderately long (HFI 54–61) and slender; mesotibia without apicoventral spur or seta; mesobasitarsus relatively short, about as long as tarsomeres II–IV taken together.

Petiolar node moderately attenuated dorsally, about 2.4 to 3.1 times higher than long (LPeI 243–314); in profile, anterior face of node convex, apex peaked, posterior face sloping posteroventrally; in dorsal view, petiole subrectangular, sides diverging posteriorly, about 2.3 to 2.9 times as broad as long (DPeI 233–286); in anterior view, petiolar outline clearly pentagonal with somewhat rounded but well-defined angles, strongly peaked; in oblique anterior view, anterior face flat; in ventral view, roughly rectangular sides weakly diverging posteriorly; subpetiolar process comparatively long, lobate, apex rounded, and directed anteroventrally; petiolar spiracles large, elliptical to weakly reniform in ventral view.

Abdominal segment 3 campaniform, widest point just anterad end of segment; sternite more or less evenly convex in profile; AS 3 with weak medial carina posteriorly broadening into a swollen lobe at around the sternite’s midline; AS 3 without carinate prora, but still with anterior face distinctly depressed and anterior margin of ventral face arcuate in ventral view; AT4 hemidemispherical and around 1.2 to 1.3 times as long as AT3 (ASI 117–128); AS 4 welldeveloped and broad, overlapping most of the width of AS 3, anterior margin straight to weakly convex in ventral view; successive abdominal segments short, telescopic, often concealed, projecting strongly anteriorly.

Sculpture of mandible punctulate, moderately shiny; ventral head surface foveolate to punctulate; remainder of head, dorsal mesosoma, lateral petiole, and abdominal segment 3 conspicuously but shallowly foveolate-reticulate to weakly areolate, sculpture on lateral mesosoma less regular, reticulum becoming rugulose, area around propodeal spiracle smoother and shiny; declivitous face of propodeum predominantly finely reticulate-punctate; anterior and dorsal petiole relatively weakly sculptured, rugulose-reticulate to granulate; AT4 finely punctulate.

Setation generally very fine, dense, mostly appressed, very short pubescence; ectal face of mandible with moderately long, curved, subdecumbent to suberect setae; masticatory margin with row of short straight setae; abdominal segments 5 to 7 with moderately short standing setae.

Color usually uniformly orange brown to chestnut brown, with appendages of lighter color.

Etymology

The species name is a patronym dedicated to Anthony D’amato and his family in honor of his contributions to the conservation of life on earth and the discovery of biodiversity. The species epithet is to be treated as an appositive noun.

Distribution and Biology

The new species is only known from Kenya, Rwanda, and Uganda ( Fig. 4F ) where it occurs in forested areas at comparatively high elevations ranging from 1448 to 2200 m. Based on data from material sampled in Kenya and Uganda, D. damato lives in leaf litter.

Comments

Discothyrea damato is in its overall gestalt characterized by the lack of specialized characters compared with most other members of the complex. It is most smilar to D. dryad , D. schulzei , and D. wakanda but lacks the standing pilosity found in these species. Additionally, the sculpture of D. damato is notably shallower relative compared with that of D. schulzei . Another species close to D. damato is D. athene , but both differ mostly in eye size (OI 0–4 vs. 5–9) and abdominal proportions (ASI 117–128 vs. 85–103).

Variation

Discothyrea damato displays some apparent intraspecific geographic variation in general body size. The material from Kenya and Uganda is significantly smaller (HW 0.37–0.39; WL 0.43–0.45) than the specimens from Rwanda (HW 0.43–0.45; WL 0.53–0.56). Nevertheless, apart from body size there is no other observable intraspecific variation.

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. 29. Stacked digital color images of D. damato sp. n. holotype (CASENT0247362). (A) body in profile, (B) body in dorsal view, (C) head in full-face view.

Fig. 30. Still images from shaded surface display volume renderings of D. damato sp. n. holotype (CASENT0247362) 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.