Discothyrea traegaordhi

Discothyrea traegaordhi
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Proceratiinae
Tribe:	Proceratiini
Genus:	Discothyrea
Species group:	traegaordhi
Species:	D. traegaordhi
Binomial name
	Discothyrea traegaordhi; Santschi, 1914 Specimen labels
Synonyms
	Discothyrea hewitti Arnold, 1916;

At present, Discothyrea traegaordhi is only known from South Africa. It seems to be moderately distributed from the Eastern Cape to Kwa-Zulu Natal. Based on the limited data available, D. traegaordhi prefers forested habitats at low to medium elevations.

Identification

Hita-Garcia and Lieberman (2019) - The following character combination distinguishes D. traegaordhi from the remainder of the species complex: smaller species (WL 0.51–0.57); shorter antennal scapes (SI 50–55); apicoventral mesotibial spur present; relatively shorter legs (HFI 54–58); petiole relatively thinner (DPeI 235–289; LPeI 236–313); gastral terga without erect setae, only with appressed pubescence.

Discothyrea traegaordhi can be grouped with Discothyrea gaia and Discothyrea poweri since they all possess a conspicuously large apicoventral spur on the mesotibia and relatively large eyes (OI 7–10). Nevertheless, the separation of these three species is straightforward. Discothyrea traegaordhi has a considerably thinner petiole (DPeI 235–289; LPeI 236–313) and shorter antennal scapes (SI 50–55) than D. poweri (DPeI 135–173; LPeI 152–194; SI 61–68). In addition, the latter species is also much larger (WL 0.67–0.84 vs. WL 0.51–0.57) and has longer legs (HFI 61–69 vs. HFI 54–58). Discothyrea gaia possesses numerous erect setae, especially on AT3, and a generally thicker petiole (DPeI 192–255; LPeI 194–264), both distinguishing it clearly from D. traegaordhi. Otherwise, these two species are morphologically very close and could be sister species

There is some slight variation in the thickness of the petiole and the coarseness of the sculpture, but all well within species-specific boundaries.

Keys including this Species

Key to Afrotropical Discothyrea

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: -28.36° to -33.56667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Afrotropical Region: Mozambique, South Africa (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Castes

Worker


Worker. .	Owned by Museum of Comparative Zoology.

Discothyrea X-ray micro-CT scan 3D model of Discothyrea traegaordhi (worker) prepared by the Economo lab at OIST.

See on Sketchfab. See list of 3D images.

Queen


Paratype of Discothyrea hewitti. Queen. Specimen code sam-ent-0011508. Photographer April Noble, uploaded by California Academy of Sciences.	Owned by South African Museum.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

traegaordhi. Discothyrea traegaordhi Santschi, 1914e: 3 (w.) SOUTH AFRICA.
- Type-material: neotype worker (by designation of Hita Garcia, Lieberman, et al. 2019: 72).
- Type-locality: neotype South Africa: KwaZulu-Natal, Town Bush, nr Pietermaritzburg (-29.5616, 30.323), 900 m., 20.i.1977 (W.L. & D.E. Brown).
- [Note: data of original holotype: South Africa: Natal, Pietermaritzburg, 21.iii.1905 (I. Trägårdh), deposited in NHMB; specimen lost (Hita Garcia, Lieberman, et al. 2019: 75). It was earlier recorded as present by Baroni Urbani, 1973b: 131, who noted it had, “only 1 antenna”.]
- Type-depository: BMNH.
- Status as species: Wheeler, W.M. 1922a: 761; Arnold, 1926: 198; Smith, M.R. & Wing, 1955: 107; Brown, 1958g: 253, 340; Bolton, 1995b: 172; Hita Garcia, Lieberman, et al. 2019: 72 (redescription).
- Senior synonym of hewitti: Hita Garcia, Lieberman, et al. 2019: 72.
- Distribution: South Africa.
hewitti. Discothyrea hewitti Arnold, 1916: 160 (q.) SOUTH AFRICA.
- Type-material: 2 syntype queens.
- Type-locality: South Africa: Grahamstown (= Makhanda), iv.1915 (Hewitt).
- Type-depositories: AMGC, SAMC.
- Status as species: Wheeler, W.M. 1922a: 761; Smith, M.R. & Wing, 1955: 107; Brown, 1958g: 253; Bolton, 1995b: 171.
- Junior synonym of traegaordhi: Hita Garcia, Lieberman, et al. 2019: 72.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Type Material

Discothyrea traegaordhi: Neotype (designated by Hita-Garcia et al., 2019), worker, KwaZulu-Natal, Town Bush, near Pietermaritzburg, 900 m, South Africa, 29°33′42″S 30°19′23″W / 29.5616°S 30.323°W / -29.5616; -30.323, 20 January 1977, W.L. & D.E. Brown, CASENT0790122, The Natural History Museum; native forest.
Discothyrea hewitti: Syntype, 1 queen, Grahamstown, ca. 533 m, South Africa, 33°18′00″S 26°32′00″E / 33.3°S 26.53333°E / -33.3; 26.53333, April 1915, Hewitt, SAM-ENT-11508, South African Museum; see Hita-Garcia et al., 2019.
Discothyrea hewitti: Syntype, 1 queen, Grahamstown, ca. 533 m, South Africa, 33°18′00″S 26°32′00″E / 33.3°S 26.53333°E / -33.3; 26.53333, April 1915, Hewitt, Albany Museum, Grahamstown, South Africa; see Hita-Garcia et al., 2019.

Description

Worker

Hita-Garcia and Lieberman (2019) - (n = 10) EL 0.03–0.05; HL 0.47–0.52; HW 0.39–0.43; SL 0.24–0.28; PH 0.25–0.28; PW 0.24–0.31; DML 0.33–0.39; PrH 0.29–0.33; WL 0.51–0.57; HFL 0.28–0.32; PeL 0.07–0.09; PeW 0.19–0.23; LT3 0.28–0.35; LT4 0.34–0.43; OI 7–10; CI 82–84; SI 50–55; LMI 47–52; DMI 48–55; DMI2 67–76; ASI 113–124; HFI 54–58; DPeI 235–289; LPeI 236–313.

Head somewhat longer than broad (CI 82–84), posterior head margin straight to weakly convex, posterodorsal corners of head broadly rounded; sides of head in frontal view convex; eyes present, relatively large (OI 7–10), round, usually comprising five to eight ommatidia, placed about a third of the way between anterolateral corner of gena and posterior head margin; eyes visible in frontal view; frontal lamella fairly short and roughly triangular in profile, apex rounded to acute; lamella not translucent across its disc, lacking a distinct fenestra; medial clypeus convex, lateral clypeus curving shallowly between antennal sockets and anterolateral corners of head, bearing short, curved setae. Antenna with short to moderately long scape (SI 50–55), scape slightly expanded apically, gently bent; pedicel subglobose, approximately as long as broad to slightly broader than long; apparent antennomere count seven to nine, but eight in most cases, flagellomeres basad apical club highly compressed, taken together shorter than apical club. Ventral head with low, V-shaped preoccipital ridge with short, triangular anteromedial projection; median area of hypostoma broadly triangular, arms narrowed, similar in width across their length; palpal formula not examined. Mandible edentate except for long, square to crenulate prebasal angle; basal angle rounded to squared; ectal face with carina originating at basal angle, becoming confluent with masticatory margin at around apical one-third, leaving narrow depressed region including prebasal angle.

Mesosoma weakly convex, pronotum either slightly higher than propodeum or at about same height; in dorsal view, mesosoma conspicuously slender and elongate (DMI 48–55; DMI2 73–83), moderately narrowed posteriorly, pronotum somewhat wider than propodeum; pronotal humeri rounded; posterior propodeal margin straight to very slightly concave; posterodorsal corners of propodeum rounded, without denticles or strong angles; declivitous face of propodeum slightly concave in profile and oblique posterior view; propodeal spiracle distinct, directed posterolaterally; propodeal lobes short, rounded.

Legs short (HFI 54–58); mesotibia with distinct apicoventral spur; mesobasitarsus relatively short, subequal in length to tarsomeres II–IV taken together.

Petiolar node weakly attenuated dorsally, about 2.4 to 3.1 times higher than long (LPeI 236–313) in profile anterior face of node straight to weakly convex, apex peaked, petiolar dorsum straight or sloping down anteriorly, posterior face subvertical; in dorsal view, node approximately rectangular, about 2.3 to 2.9 times broader than long (DPeI 235–289), sides divergent posteriorly; in anterior view, petiolar outline broadly pentagonal to round, angles rounded; in oblique anterior view; anterior face flat; subpetiolar process variable in shape, moderately long, broadly lobate, subrectangular to rectangular.

Abdominal segment 3 campaniform, widest just anterad end of segment; tergite slightly anteriorly prolonged over petiole; sternite evenly curved to posteriorly bulging in profile; AS3 without median ridge, posterior lobe broad and indistinct; prora carinate, concave in ventral view; AT4 around 1.1 to 1.2 times longer than AT3 (ASI 105–124); AT4 evenly rounded hemidemispherical; AS4 with anterior lip overlapping about median two-third the width of AS3, anterior face convex in ventral view; successive abdominal segments short, telescopic, often concealed.

Sculpture of head, mesosoma, petiole, and abdominal segment 3 shallowly punctate-reticulate; mandibles moderately shining with piligerous punctulae; punctae on lateral mesosoma somewhat larger but sparser; absent or nearly so on declivitous face of propodeum, the disc of which more strongly shining than remainder of mesosoma; fine rugulae present on ventrolateral and declivitous surfaces of propodeum; AT4 with minute but distinct, very densely arranged piligerous punctae, clearly shinier than AT3.

Setation mostly consisting of appressed white pubescence, more or less evenly distributed over entire body, sometimes more diluted on head; abdominal segments five through seven with long, flexuous standing setae; appendages with well-developed, evenly distributed appressed pubescence; ectal face of mandible with abundant, curved, appressed to decumbent setae; with row of straight, stout setae on masticatory margin.

Color unicolorous luteous to matte orange brown to darker chestnut brown with lighter appendages.

Type Material

Hita-Garcia and Lieberman (2019) - The original holotype with the data SOUTH AFRICA, Natal, Pietermaritzburg, 21.III.1905 (Tragaordh) (NHMB: CASENT0915310) is presumably lost. The pin with the original label located in the collection of NHMB lacks a specimen. This was confirmed by us, as well as by the curatorial staff of NHMB. Since the original description does not provide sufficient diagnostic information to properly delineate this species and no type material exists, we consider it necessary to designate a neotype in order to clarify and stabilize the taxonomic and nomenclatorial status of D. traegaordhi. The chosen neotype is from the same area around Pietermaritzburg in Kwa-Zulu Natal as the original holotype representing a very close geographical approximation to the type location from the original publication.

See the beginning of this ("Nomenclature") section for detailed information about the specimen types. A cyber-type of the neotype is also available. This includes: volumetric raw data (in DICOM format), 3D rotation video, still images of surface volume rendering, a 3D surface (in PLY format) of the physical neotype (The Natural History Museum: CASENT0790122), stacked digital color images illustrating the head in full-face view, and both profile and dorsal views of the body. The data are deposited at Dryad and can be freely accessed as virtual representations of the type. There is also a Sketchfab 3D surface model of the holotype. It is shown above, in the Caste section, and at Sketchfab (see the link in the Caste Section).

References

Brown, W. L., Jr. 1958g. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118: 173-362 (page 340, see also)
Hita-Garcia, F., Lieberman, Z., Audisio, T.L., Liu, C., Economo, E.P. 2019. Revision of the highly specialized ant genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with x-ray microtomography and 3D cybertaxonomy. Insect Systematics and Diversity 3(6): 5; 1–84 (doi:10.1093/isd/ixz015).
Santschi, F. 1914e. Meddelanden från Göteborgs Musei Zoologiska Afdelning. 3. Fourmis du Natal et du Zoulouland récoltées par le Dr. I. Trägårdh. Göteb. K. Vetensk. Vitterh. Samh. Handl. 15: 1-44 (page 3, worker described)

References based on Global Ant Biodiversity Informatics

Arnold G. 1916. A monograph of the Formicidae of South Africa. Part II. Ponerinae, Dorylinae. Annals of the South African Museum. 14: 159-270.
Arnold G. 1926. A monograph of the Formicidae of South Africa. Appendix. Annals of the South African Museum. 23: 191-295.
Brown W. L., Jr. 1958. Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bulletin of the Museum of Comparative Zoology 118: 173-362.
Hita-Garcia F., Z. Lieberman, T. L. Audisio, C. Liu, and E. P. Economo. 2019. Revision of the highly specialized ant genus Discothyrea (Hymenoptera: Formicidae) in the Afrotropics with X-ray microtomography and 3D cybertaxonomy. Insect Systematics and Diversity 3(6): 5:1-84.
Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004