Discothyrea, Roger, 1863

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: 13-18

publication ID

http://doi.org/ 10.1093/isd/ixz015

persistent identifier

http://treatment.plazi.org/id/03D9AC4A-E559-FFAA-FCC4-F99DBEB0055D

treatment provided by

Plazi

scientific name

Discothyrea
status

 

Identification Key to Afrotropical Discothyrea  

Species (Workers)

1. Frontal carinae produced as a broad, elevated rhomboid plate, roof-like in profile ( Fig. 5A and B View Fig ); antennal scrobes present, deep, extending from antennal insertions to just anterad the eye ( Fig. 5E and F View Fig ); eye present, well-developed with multiple silvery globose ommatidia protruding from head (even when eye small) ( Fig. 6A and B View Fig ); AT3 much longer than AT4, around 1.9 to 2.2 times ( ASI <60) ( Fig. 2A View Fig ). [ D. oculata   -complex]...........2

- Frontal carinae reduced to thin medial lamella, broadly lobate to acutely triangular in profile ( Fig. 5E and F View Fig ); antennal scrobes absent ( Fig. 5E and F View Fig ); eye variable: either absent, a simple pigmented spot, or if with multiple ommatidia, if the latter then

eye small and ommatidia flattened, not protruding from head ( Fig. 6 View Fig C–T); AT3 never as long as above, usually AT3 equal in length or shorter than AT4, sometimes AT3 up to 1.2 times longer than AT4 ( ASI 85–168) ( Fig. 2B and C View Fig ). [ D. traegaordhi   - complex].................................................................................3

2. Eyes small (OI 5–9), situated laterally on gena ( Figs. 6A View Fig and 7A View Fig ); propodeum angulate to dentate, angles subtended and medially joined by narrow carinulae such that propodeum laterally and dorsally marginate ( Fig9A View Fig ); propodeal declivity with median carina but without costae or rugae ( Fig. 11A View Fig ). [ Angola, Cameroon, Central African Republic, Democratic Republic of Congo, Ghana, Ivory Coast, Kenya, Liberia, Mozambique, Tanzania, South Africa, Uganda]................................. D. mixta  

- Eyes large (OI 14–16), situated anterolaterally on gena ( Figs. 6B View Fig and 7B View Fig ); propodeum not angulate or dentate (though declivity concave), lacking carinulae and not marginate ( Fig. 9B View Fig ); propodeal declivity deeply costate to rugose. ( Fig. 11B View Fig ). [ Cameroon, Democratic Republic of Congo, Ghana, Guinea, Ivory Coast, Kenya, Mozambique, Nigeria, Tanzania, Zimbabwe]............................................................... D. oculata  

3. Mesotibia with conspicuous apicoventral spur ( Fig. 13 View Fig A–C).....4

- Mesotibia without a conspicuous apicoventral spur; either apically unarmed or with small, distinct seta inserted in apicoventral pit ( Fig. 13 View Fig D–F).......................................................................6

4. Dense layer of appressed pubescence with numerous short, but conspicuously standing setae present on abdominal terga ( Figs. 14H View Fig and 33A View Fig ); mandible without prebasal angle or denticle ( Fig. 8H View Fig ). [ Zimbabwe]............................................ D. gaia  

- Abdominal terga without any standing setae, only with appressed pubescence ( Fig. 14P and R View Fig ); mandible with small prebasal denticle ( Fig. 8P View Fig ) or prebasal irregularly shaped median carina ( Fig. 8R View Fig )...............................................................5

5. Generally larger species (WL 0.67–0.84); antennal scapes longer (SI 61–68); legs longer (HFI 61–69); petiole exceptionally thick (DPeI 135–173; LPeI 152–194) ( Figs. 50A, B View Fig , and 51L View Fig ); mandible with small, sharp prebasal denticle (8P); sculpture shallow overall, especially smooth on clypeus, propodeal declivity, petiole, and AT3 ( Figs. 6P View Fig , 9P View Fig , 10P View Fig , and 12P View Fig ). [ South Africa]....................................................................... D. poweri  

- Generally smaller species (WL 0.51–0.57); antennal scapes shorter (SI 50–55); legs shorter (HFI 54–58); petiole thinner (DPeI 235–289; LPeI 236–313) ( Figs. 54A, B View Fig , and 55L View Fig ); mandible with broad prebasal irregularly shaped median carina ( Fig. 8R View Fig ); sculpture coarser overall, especially on clypeus, propodeal declivity, petiole, and AT3 ( Figs. 6R View Fig , 9R View Fig , 10R View Fig , 12R View Fig ). [ South Africa] .................................................... D. traegaordhi  

6. Larger species (HW 0.57–0.61; WL 0.80–0.90); mesosoma high-rounded, profile extremely convex ( Fig. 9C View Fig ); propodeum rounded to weakly angulate; first mesotarsomere very elongated, about as long as remaining tarsomeres taken together ( Fig. 24R View Fig ). [ Tanzania]................................................ D. aisnetu  

- Smaller species (HW 0.30–0.49; WL 0.38–0.59); mesosomal profile usually ranging from almost flat to weakly moderately convex ( Fig. 9D, F, G View Fig , J–M, Q, and T); if mesosoma well rounded, then propodeum conspicuously dentate ( Fig. 9O and S View Fig ); first tarsomere variable in length but never as long as above, usually subequal to tarsomeres II–IV taken together ( Figs. 26R View Fig , 28R View Fig , 32R View Fig , 36R View Fig , 38R View Fig , 40R View Fig , and 57R View Fig ).......................................7

7. Masticatory margin of mandible with a prominent, welldeveloped preapical tooth, clearly larger than prebasal denticle or acute basal angle (8E, I); head very broad, subquadrate (CI 87–92), anterolateral corners of gena angulate to denticulate ( Fig. 6E and I View Fig ).........................................................................8

- Masticatory margin of mandible without preapical tooth, or if small preapical denticle or angle present, then not well-developed and not clearly larger than prebasal denticle or acute basal angle ( Fig. 8D, F, G View Fig , J–M, O, Q, S, T); head not as above: usually not as broad (CI 77–89), and anterolateral corner of gena not angulate ( Fig. 6D, F, G, J, L, M, O, Q, S, T View Fig ); if gena somewhat angulate, then head especially elongate (CI 78) ( Fig. 6K View Fig ).........................9

8. Dorsal surfaces and antennal scape without standing pilosity, with appressed or decumbent pubescence only ( Figs. 14E View Fig and 27A View Fig ); medial clypeus transverse in frontal view ( Fig. 6E View Fig ); eye larger (OI 6); preapical mandibular tooth exceptionally large, strongly curved; apical angle of mandible acute ( Fig. 8E View Fig ). [ Tanzania]................................................................ D. chimera  

- Standing pilosity present and abundant on all dorsal surfaces and antennal scape ( Figs. 14I View Fig and 35A View Fig ); medial clypeus emarginate in frontal view ( Fig. 6I View Fig ); eye absent or tiny (OI 0–4); preapical mandibular tooth smaller and not strongly curved; apical angle of mandible squared to notched ( Fig. 8I View Fig ). [ Rwanda, Tanzania]................................................................ D. gryphon  

9. AT4 conspicuously enlarged, bulbous, much larger and longer than AT3 ( ASI 158–183) ( Fig.12S View Fig ); posterior propodeum laterally and dorsally strongly concave; declivitous face of propodeum mostly smooth, ventral portion transversely substrigulate, clearly

differently sculptured than remainder of mesosoma. [ Angola, Cameroon, Ghana, Ivory Coast, Uganda] ..................... D. venus  

- Character combination never as above; AT4 equal in length to AT3, or if longer then ratio smaller ( ASI 100–142) ( Fig. 12D, F, G View Fig , J–M, O, Q, and T); posterior propodeum variably shaped; declivitous face of propodeum variable, but usually entire surface well-sculptured or entire surface smooth........................10

10. Mesosomal and abdominal dorsa with standing pilosity (sometimes best seen in silhouette or on AT 4 in dorsal view, but visible at low magnification) ( Fig. 14G, M, Q, T View Fig , 31A View Fig , 43A View Fig , 52A View Fig , and 58A View Fig )...............................................................................11

- Usually mesosomal and abdominal dorsa without standing pilosity, sometimes abdominal dorsa with short, standing pilosity, but then no standing pilosity on dorsum of mesosoma ( Figs. 14D, F View Fig , J–L, N, O, 25A, 29A, 37A, 39A, 46A, and 48A)..................14

11. Propodeum strongly dentate with deeply concave declivity ( Fig. 9M View Fig ); abdominal sternite 3 with strong median ridge anteriorly surpassing prora, appearing distinctly rectangular in profile ( Fig. 12M View Fig ); petiolar outline rectangular with pointed dorsolateral angles, anterior face of petiolar node strongly impressed, appearing bilobed in oblique anterior view ( Fig. 44M and N View Fig ). [ Tanzania].................................................. D. michelae  

- Propodeum denticulate to weakly dentate with only moderately concave declivity ( Fig. 9G, Q View Fig , and T); abdominal sternite 3 without a median ridge or if ridge present, not anteriorly surpassing prora, sternite not rectangular in pofile ( Fig. 12G, Q View Fig , and T); petiole pentagonal to hexagonal, never rectangular, anterior face of petiolar node flat to weakly impressed, never appearing bilobed in oblique anterior view ( Figs. 32M, N View Fig , 53M, N View Fig , and 59M, N View Fig )....................................................................12

12. Mesosoma comparatively elongate and slender (DMI2 87–91; LMI 45–49) ( Fig. 10G View Fig ); frontal lamella bladelike, apex angulate in profile. [ Kenya]................................................. D. dryad  

- Mesosoma comparatively robust and stocky (DMI2 93–100; LMI 49–57) ( Fig.10Q and T View Fig );frontal lamella disciform to lobate, apex rounded in profile.........................................................13

13. Smaller species (WL 0.47–0.56; HW 0.39–0.44) with eyes smaller or absent (OI 0–3) ( Fig. 7Q View Fig ) and shorter legs (HFI 55–60); sculpture similarly coarse overall, not notably reduced on petiole or abdominal sternite 3 ( Figs. 12Q View Fig and 59Q View Fig ). [ Rwanda, Uganda]. .................................................. D. schulzei  

- Larger species (WL 0.59–0.65; HW 0.50–0.52) with larger eyes (OI 4–7) ( Fig. 7T View Fig ) and longer legs (HFI 63–68); sculpture on petiole and abdominal segment 3 reduced ( Fig. 12T View Fig ), abdominal sternite 3 very smooth medially ( Fig. 59T View Fig ). [ Democratic Republic of Congo] ............................................... D. wakanda  

14. Surface sculpture very reduced, entire body quite smooth with only minute, shallow punctulation ( Fig. 9N View Fig ); propodeum not strongly angulate or denticulate ( Fig. 9N View Fig ) [ Kenya, Tanzania]..... ................................................................................. D. patrizii  

- Surface sculpture on head, mesosoma, and AT3 well-developed and coarse, predominantly punctate to foveolate-reticulate ( Fig. 9D, F View Fig , J–L, and O); propodeum angulate to strongly denticulate ( Fig. 9D, F View Fig , J–L, and O).............................................15

15. Mesosoma robust and stocky (DMI2 92–102; LMI 47–56) ( Fig. 10D, F View Fig , and O); head broader (CI 79–89) ( Fig. 6D, F View Fig , and O).........................................................................................16

- Mesoma more slender and elongate (DMI2 81–87; LMI 42–53) ( Fig. 10 View Fig J–L); head narrower and more elongate (CI 78–80) ( Fig. 6 View Fig J–L).............................................................................18

16. Propodeum dentate, teeth well-developed ( Fig. 9O View Fig ); lateral propodeum with smooth, unsculptured patch dorsad propodeal spiracle ( Fig. 9O View Fig ); abdominal sternite 3 with strongly developed, narrow median ridge, sternite squared in profile (12O); frontal lamella thick and platelike ( Fig. 6O View Fig ), in profile rhomboid with three clearly demarcated faces, lacking basal fenestra ( Fig. 7O View Fig ). [ Ivory Coast]............................................ D. penthos  

- Propodeum angulate but without differentiated teeth ( Fig. 9D and F View Fig ); lateral mesosoma similarly sculptured over entire surface, without distinct smooth patch on propodeum ( Fig. 9D and F View Fig ); abdominal sternite 3 without a median ridge or ridge broad and rounded, sternite sloping to round in profile (12D, F); frontal lamella narrow ( Fig. 6D and F View Fig ), not rhomboid in profile, usually with well-defined basal fenestra ( Fig. 7D and F View Fig ).............................................................................................17

17. Petiolar outline in anterior view strongly pentagonal with dorsal faces well-defined and very tall triangular peak ( Fig. 30M, N View Fig ); eye absent to small (OI 0–4) ( Fig. 7F View Fig ); AT4 longer than AT3 ( ASI 117–128) ( Fig. 12F View Fig ); petiole thicker, less strongly attenuated (DPeI 233–286; LPeI 243–314). [ Kenya, Rwanda, Uganda, Democratic Republic of Congo]............................... D. damato  

- Petiolar outline in anterior view weakly pentagonal, dorsal faces poorly defined and with low, rounded peak ( Fig. 26M, N View Fig ); eye present, relatively large (OI 5–9) ( Fig. 7D View Fig ); AT4 somewhat shorter than or subequal to AT3 ( ASI 85–103) ( Fig. 12D View Fig ); petiole thinner, more strongly attenuated (DPeI 300–500; LPeI 286–500). [ Kenya, Mozambique, Rwanda, Tanzania, Uganda].. .................................................................................. D. athene  

18. Anterolateral corners of gena rounded, not sharply angulate ( Fig. 6J View Fig ); abdominal sternite 3 without narrow median ridge, sternite sloping in profile with poorly-defined anterior face ( Fig. 12J View Fig ); petiolar outline in anterior view roughly hexagonal, dorsal face flat ( Fig. 38M and N View Fig ). [ Tanzania].......... D. hawkesi  

- Anterolateral corners of gena sharply angulate ( Fig. 6K and L View Fig ); abdominal sternite 3 with narrow median ridge, sternite truncate to squared in profile with clearly defined anterior face ( Fig. 12K and L View Fig ); petiolar outline in anterior view roughly pentagonal, dorsally peaked ( Figs. 40M, N View Fig , and 42M, N View Fig ).............19

19. Mesosomal profile more robust (LMI 53), dorsum convex, propodeal denticles larger, propodeal declivity more strongly concave ( Fig. 9L View Fig ); legs longer (HFI 65) and very slender, first mesotarsomere elongate, longer than tarsomeres II–IV taken together; antennal scape longer (SI 58). [ Zimbabwe]........ D. maia  

- Mesosomal profile more gracile (LMI 42), dorsum sloping posteriorly but not convex, propodeal denticles smaller, propodeal declivity more shallowly concave ( Fig. 9K View Fig ); legs shorter (HFI 51) and not exceptionally slender, first mesotarsomere short, about as long as tarsomeres II–IV taken together; antennal scape shorter (SI 51). [ Tanzania]............................... D. kalypso  

ASI

Ascension Conservation