Dinoponera snellingi, Lenhart & Dash & Mackay, 2013

Lenhart, Paul A., Dash, Shawn T. & Mackay, William P., 2013, A revision of the giant Amazonian ants of the genus Dinoponera (Hymenoptera, Formicidae), Journal of Hymenoptera Research 31, pp. 119-164 : 150-155

Dinoponera snellingi sp. n. Figs 4D, 4I, 4N , 5B , 7 , 9B , 10B , 11B , 13

Worker.

Unknown.

Male diagnosis.

Specimens of this species are distinct in several respects. The combination of a bicolored body and head possessing bulging compound eyes and ocelli ( Fig. 4D ) is unique to this species. More definitive is the shape of the aedeagus which possesses a large ventral lobe and finger-like serrated flange ( Fig. 11B ). The short broad digitus volsellaris with finely toothed basal lobe ( Fig. 10B ) is distinctive, as well as the paramere shape ( Fig. 9B ).

Description of the male.

Measurements (mm) (n=3) TBL: 16.14-17.09 (16.58); HL: 1.90-2.05 (1.98); HW: 2.36-2.51 (2.44); SL: 0.62-0.72 (0.65); EL: 1.23-1.38 (1.32); EW: 0.72-0.82 (0.79); WL: 5.54-6.05 (5.77); FWL: 13.33-13.63 (13.43); HWL: 9.93-10.46 (10.25); PL: 1.44-1.54 (1.49); PH: 1.13-1.23 (1.16); PW: 0.92-1.13 (1.04); GL: 6.66-7.18 (6.94); HFL: 4.20-4.92 (4.54). Integument: smooth and shining; head, mesosoma and petiole dark brown to black; gaster light brown. Head: Mandibles reduced, rounded, lacking teeth, rounded lobe on ventro-basal edge, high lateral ridge running along axis; palps elongated; labrum reduced, deeply emarginated on distal margin, covered with setae. Clypeus large, triangular, bulging medially, covered in appressed to subdecumbent setae; anterior tentorial pits large; frontal carinae reduced to slight ridge along antennal socket; antennal sockets close, located at posterior apex of clypeus. Antennae: black; funiculus covered in minute, dense, stiff subdecumbent setae ( Fig. 4I ); scape shorter than second funicular segment, 1st funicular segment reduced. Compound eyes large, along lateral side of head, deeply emarginated border medially. 3 ocelli at posterior margin of head, bulging beyond margin of head, depressed area between posterior ocelli. Entire head covered in short decumbent to erect setae ( Fig. 3 ). Mesosoma: covered in short suberect to decumbent white setae; pronotum triangular, exposed narrowly dorsally anterior to scutum; scutum large, bulging antero-dorsally, with 3 longitudinal carinae; small tegula over insertion of forewing; scutellum domed, with sparse erect setae, sides with vertical carina, dorsal surface smooth; basilar sclerite under hind wing reduced; fused mesopleuron, separated by furrow with mesosternite; metanotum exposed between scutellum and propodeum, reduced; mesoepimera, mesoepisternite and propodeum fused, rounded; coxa large, conical, covered in dense subdecumbent to decumbent setae. Wings: covered in dense minute setae, venation as shown in Fig. 5B . Legs: black, covered in minute subdecumbent to decumbent stiff setae; one well-developed, antennae cleaning, pectinate spur on the fore tibia; spine-like and less developed denticular comb on meso-thoracic tibia; spine and comb-like spur on hind tibia; tarsal claws bidentate. Petiole: narrow attachments at base to the propodeum and gaster; petiole humped dorso-posteriorly; subpetiolar process reduced, bulging slightly posteriorly. Gaster: large, cylindrical; covered in fine silvery suberect to subdecumbent setae; first gastric tergite broadly rounded; pygidium terminating in short, broad, triangular, spine ( Fig. 4N ); cerci short, as long as pygidial spine, covered in erect setae; tabular subgenital plate with posterior end rounded. Genitalia: ( Fig. 7 ) basal ring with thick dorso-anterior loop structures, reduced; parameres short, broad, rounded, large lobe on dorsal edge, emarginated ventro-basal edge ( Fig. 9B ); volsella with rounded cuspis volsellaris with raised rounded bumps on medial-ventral surface, digitus volsellaris with numerous small circular bumps on lateral distal face, tuft of setae on ventro-distal edge, lobe on basal ventral corner, covered in minute teeth ( Fig. 10B ); penis valve of aedeagus with long lateral arm of aedeagal apodeme at anterior border, ventral concavity under ridge at base of apodeme, dorsal edge broadly rounded, ventral tooth projecting into thin anteriorly folded flange with heavy serration, rounded notch at base, large triangular ventral lobe with finely serrated edge and vertical ridge running through middle of lobe, edge of lobe continuing into lateral apical fold with serrated edge ( Fig. 11B ).

Distribution.

Known only from type locality; Campo Grande, Brazil ( Fig. 13 ).

Discussion.

Dinoponera snellingi is a new species based on the suite of morphological characters presented in the diagnosis above. Most important are the shape of the aedeagus, volsella and parameres all of which we consider apomorphic characters. The type specimen males were unassociated with workers. Initially Dinoponera snellingi specimens were considered males of Dinoponera australis ; as workers of this species were collected at the same location and at the same date (see Dinoponera australis materials examined). Additionally the specimens shared the same character states of bicoloration and short pygidial spine that Kempf (1971) used to designate Dinoponera australis . However, the size of the compound eyes (compare Fig. 4D and 4E ), bulging ocelli at the posterior of the head (compare Fig. 4D and 4E ), short broad volsella with large tear drop-shaped basal lobe ( Fig. 10B ) and penis valve of the aedeagus with disto-lateral process, disto-ventral lobe and serrated flange on the ventral edge ( Fig. 11B ) provide strong evidence supporting that these male specimens represent a novel species.

We have compared male specimens of Dinoponera snellingi with those of Dinoponera australis collected in nest series and found they differ in the characters listed above. Campo Grande is within the range of Dinoponera mutica and there is a possibility that these specimens represent the currently unknown males of Dinoponera mutica . However, the males of Dinoponera snellingi are closest in character states to the male of Dinoponera australis , the worker caste of which differs greatly in many characters from the other known Dinoponera workers including Dinoponera mutica (see the Dinoponera australis discussion). Therefore we hypothesize that the male of Dinoponera mutica will most likely be similar to Dinoponera quadriceps or Dinoponera longipes , based on the similar worker morphology, and the unknown worker of Dinoponera snellingi will be similar to the worker of Dinoponera australis . Species groupings based on worker and male character states overlap; leaving Dinoponera australis with Dinoponera snellingi allied and separate from the other Dinoponera species. Until associated workers are discovered, we contend that it is better to describe these unique males rather than allow them to remain misidentified and unstudied or describe them as males of Dinoponera mutica with only anecdotal evidence as justification.

Etymology.

Namedin honor of the late Roy Snelling who made considerable contributions to the field and spirit of myrmecology.

Type series.

Holotype deposited in MZSP, BRAZIL, Mato Grosso do Sul, Campo Grande, 12 Oct 1989, W.P. Mackay #12404, 2 paratypes, same locality, 8 Oct 1989, #12359 collected at house light (deposited in the CWEM and MCZC).

Figures

Figure 3. Dinoponera longipes male. Head in full frontal view; body in lateral view with wings not shown.

Figure 4. Features of Dinoponera males. A-E Head, frontal view F-J Right scape, first and second funicular segments, frontal view K-O Pygidial spine, dorsal view A, F, K Dinoponera gigantea B, G, L Dinoponera quadriceps C, H, M Dinoponera longipes D, I, N Dinoponera snellingi E, J, O Dinoponera australis.

Figure 5. Wings of known males. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 7. Dinoponera snellingi male genitalia. A dorsal view B lateral view C ventral view.

Figure 9. Dinoponera rightbasiparamere / paramere of known males, lateral view. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 10. Dinoponera rightvolsella of known males, lateral view. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 11. Dinoponera rightpenis valves from the aedeagus of known males. A Dinoponera quadriceps B Dinoponera snellingi C Dinoponera gigantea D Dinoponera australis E Dinoponera longipes.

Figure 13. Distribution map of Dinoponera species. Symbols in black are records added by this study; open symbols are from literature sources (Kempf 1971, 1975, Araujo et al. 1990, Peeters et al. 1999, Monnin and Peeters 1999, Fourcassie and Oliviera 2002, Monnin et al. 2003, Mariano et al. 2004, Araujo and Rodriques 2006, Marques-Silva et al. 2006).