Patagonomyrmex odoratus, Johnson, Robert A. & Moreau, Corrie S., 2016

Johnson, Robert A. & Moreau, Corrie S., 2016, A new ant genus from southern Argentina and southern Chile, Patagonomyrmex (Hymenoptera: Formicidae), Zootaxa 4139 (1), pp. 1-31 : 22-27

Patagonomyrmex odoratus NEW COMBINATION

( Figures 9–11 )

Pogonomyrmex (Ephebomyrmex) odoratus Kusnezov, 1949: 302 , figs. 1, 2 (worker, queen, male). Syntypes examined: 6 workers, 3 alate queens [FML], 11 workers, 7 alate queens [LACM], 2 workers, 1 alate queen [MLPA], 12 workers, 4 alate queens, 2 males [USNM], ARGENTINA, Río Negro: Bariloche, Cerro Otto, #3554 (N. Kusnezov leg., 6 February 1949); #3553—same data as lectotype: 6 workers, 3 males [FML]. See also Kusnezov, 1960: fig. unnumbered, pg. unnumbered. USNM worker here designated LECTOTYPE [CASENT0914807].

Ephebomyrmex odoratus ( Kusnezov); Kusnezov, 1960 : 354, first combination in Ephebomyrmex .

Pogonomyrmex odoratus Kusnezov ; Snelling & Hunt, 1976: 75, fig. 25, revived combination in Pogonomyrmex .

Worker. Diagnosis. This species is uniquely characterized by the following combination of features: (1) longitudinal rugae on cephalic dorsum rarely continue to posterior margin, (2) interrugae on cephalic dorsum and dorsum of promesonotum mostly smooth and shining, (3) posterior surface of petiolar node smooth and shining, (4) inferior propodeal spines triangular, length and width similar, notably shorter than superior spines, and (5) head and mesosoma mostly concolorous amber-orange to brownish-orange, gaster usually darker orangish-black ( Figure 9 ).

Measurements. Lecotytpe (n = 4 + 9 paralectotypes). HL 1.27 (1.00–1.25); HW 1.11 (0.86–1.08); MOD 0.27 (0.24–0.29); OMD 0.18 (0.15–0.24); SL 0.91 (0.79–0.96); PNW 0.74 (0.62–0.73); HFL 1.12 (0.94–1.15); ML 1.52 (1.18–1.60); PW 0.30 (0.20–0.30); PPW 0.47 (0.39–0.45). Indices: SI 81.98 (79.63–96.00); CI 87.05 (82.46– 95.50); OI 24.32 (24.53–27.91); HFI 100.90 (91.43–110.64) (see also Kusnezov, 1949).

Redescription. Longitudinal rugae on cephalic dorsum prominent, widely-spaced, weakly wavy, beginning on frontal lobes but rarely extending to posterior margin; posterior margin flat in full-face view. Wavy to irregular, often discontinuous rugae arc from mandibular margins to frontal lobes and traverse longitudinally above and below eyes, usually terminating before reaching vertex; lateral rugae weaker than those on cephalic dorsum. Interrugae on cephalic dorsum smooth and shining; vertex and posterior margin of head weakly granulate-punctate, weakly shining to smooth and shining. Dorum of clypeus with several moderately coarse, subparallel, longitudinal rugae. Mandible with six teeth; mandibular dorsum strongly rugose. MOD ranging from 0.21–0.25x HL. In profile, eyes situated anterior to middle of head, OMD = 0.57–0.89x MOD. In full-face view, eyes protruding slightly beyond lateral margins of head. Antennal scapes long (SI = 79.63–96.00), surpassing vertex by less than length of second funicular segment; scapes weakly to moderately granulate-punctate, often with faint striae, weakly shining; basal flange moderately well-developed with carinate margin.

Mesosomal profile strongly convex; dorsum of promesonotum smooth and shining; longitudinal rugae on mesospleura and metapleura wavy to irregular, interrugae weakly to moderately granulate-punctate, weakly shining. Promesonotal suture absent to weakly impressed on occasional individuals. Superior propodeal spines long, narrowing to blunt tip, length rarely exceeding 0.6–0.7x the distance between their bases; inferior propodeal spines moderately well-developed, triangular, acuminate to bluntly tipped, length and width similar, distinctly shorter than superior spines. Propodeal spiracles weakly ovate to circular facing posterad. Legs weakly granulate to smooth, weakly shining to shining.

Peduncle of petiole about as long as petiolar node, anteroventral margin of peduncle of petiole with a small, acuminate spine. In profile, posterior surface of petiolar node weakly convex; petiolar node asymmetrical with anterior surface shorter than posterior surface, apex rounded to bluntly angulate. In dorsal view, petiolar node longer than wide, sides subparallel, narrowing to rounded to bluntly angulate anterior margin. Dorsum of postpetiole convex in profile; in dorsal view, widest near posterior margin, narrowing to anterior margin, maximum width and length similar; posterior surface and sides of petiolar node and dorsum and sides of postpetiole smooth and shining; first gastral tergum smooth and shining.

Erect, short to long, copperish-brown hairs abundant on head, one to few approach to slightly exceed MOD. Moderately abundant subdecumbent to decumbent hairs on antennal scapes; abundant decumbent to appressed hairs on funicular segments. Legs with moderately abundant subdecumbent to decumbent setae. Mesosoma with moderately dense, medium to long, erect setae, longest approaching MOD; petiolar node, postpetiole, gastral terga with moderately dense erect setae, mostly similar in length, longest notably shorter than MOD. Body other than gaster mostly concolorous amber-orange to brownish-red, medial portion of cephalic dorsum usually slightly darker than rest of head; gaster dark orangish-black to brownish-black ( Figure 9 ).

Queen. Diagnosis. This caste is diagnosed by: (1) caste-specific morphology of the mesosoma related to wingbearing and presence of ocelli on head, (2) mesoscutum and mesoscutellum smooth and shiny, (3) inferior propodeal spines triangular, much shorter than superior propodeal spines, and (4) body orangish-brown, gaster slightly darker ( Figure 10 ).

Measurements —(n = 9 + 3 paralectotypes). HL 1.21–1.26; HW 1.05–1.12; MOD 0.30–0.33; OMD 0.17– 0.24; SL 0.83–0.97; PNW 0.85–0.93; HFL 1.03–1.14; ML 1.52–1.77; PW 0.26–0.33; PPW 0.49–0.54. Indices: SI 79.05–89.81; CI 83.33–92.56; OI 27.52–30.28; HFI 96.26–106.67 (see also Kusnezov, 1949).

Male. Diagnosis. This caste is diagnosed by: (1) mesopleura, metapleura, pronotal sides and/or dorsum of propodeum with weak to strong rugae, (2) no hairs on ventral surface of head or those protruding from mandibles approach MOD, and (3) in profile, juncture between cephalic dorsum and posterior declivity (near posterior margin of ocelli) strongly angulate; posterior declivity strongly concave ( Figure 11 ).

Measurements —(n = 2 + 1 paralectotype). HL 1.08–1.22; HW 0.90–1.01; MOD 0.41–0.45; OMD 0.16–0.19; SL 0.28–0.33; HFL 0.98–1.17; ML 1.71–1.75; PW 0.23–0.27; PPW 0.38–0.42. Indices: SI 29.17–36.67; CI 82.79– 85.71; OI 43.75–45.56; HFI 102.08–123.33 (see also Kusnezov, 1949).

Additional material examined. ARGENTINA: Chubut: Laguna Verde, Feb 17, 1949 ( LACM). Neuquén: Lago Tromen, 1050 m, Jan 9, 1995 ( MCZ; PSWC; UCDC); Parque Nacional Lanín, Pucara, Jan 24, 1999 ( FML); Brazo Huemel Nahual Huapi Lago, 2840’, Jan 26, 2011 ( MCZ; RAJC). Río Negro: Bariloche, Jun 2, 1949 & Feb 6, 1949 ( LACM; MCZ; MLPA); Laguna Frías, 760 m, Nov 16, 1966 ( CASC); Isla Victoria Bariloche, Jan 15, 1972 ( MZUSP); Cerro Lopez, 1700 m, Jan 2005 ( RAJC). CHILE: La Araucanía: Parque Nacional Nahuelbuta, Dec 14, 1972 ( LACM). Metropolitan: La Reserva Nacional Río Clarillo, comuna Pirque (33o 41’S, 70o 34’W) (not examined, literature record from Solervicens et al., 1991). O’Higgins: Baños de Flaco, 1940 m (not examined, literature record from Ipinza-Regla, Covarrubias, & Guevara, 1983) ( Figure 5 C).

Etymology. In his description, Kusnezov did not give information regarding the naming of this species. However, Kunezov (1960) indicated that the name was derived from the odor emitted by the species.

Discussion. Patagonomyrmex odoratus co-occurs with Pa. angustus and Pa. laevigatus . Patagonomyrmex odoratus can be distinguished from Pa. angustus based on the following characters: (1) dorsum of promesonotum and posterior surface of petiolar node smooth and shining (both structures moderately granulate in Pa. angustus ), and (2) inferior propodeal spines triangular, shorter than superior propodeal spines (inferior propodeal spines elongate with length similar to that of superior propodeal spines in Pa. angustus ). In his key, Kusnezov (1951) separated Pa. odoratus from Pa. laevigatus based on the orangish-brown body with a slightly darker gaster in Pa. odoratus versus mostly concolorous blackish to black body in Pa. laevigatus . Kusnezov (1949, 1951) also indicated that the longitudinal rugae on the cephalic dorsum were less coarse in Pa. odoratus than in Pa. laevigatus , but I could not discern this difference. He also indicated the angle between the peduncle of the petiole and the anterior surface of the petiolar node was more rounded in Pa. laevigatus , and more angulate in Pa. odoratus . This character appeared to be very subtle and inconsistent, and thus was not a useful diagnostic trait. We did not find any morphological measurements that could be used to separate Pa. odoratus from its two congeners.

In his description of this species, Kusnezov (1951) listed six localities at which Pa. odoratus had been collected, but he did not designate a type locality. In their treatment of the ants of Chile, Snelling & Hunt (1975) chose Hua Hum as the type locality because it was the first of six localities listed by Kusnezov (1949). Our designation of a lectotype supercedes this act, and the type locality is now Cerro Otto, Río Negro Province, Argentina.

Figures

FIGURE 5. Geographic distribution of: (A) Patagonomyrmex angustus (Mayr), (B) Patagonomyrmex laevigatus (Santschi), and (C) Patagonomyrmex odoratus (Kusnezov); the larger filled black circle in each panel (when present) denotes the type locality.

FIGURE 9. Photograph of Patagonomyrmex odoratus (Kusnezov) lectotype worker: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (CASENT 0914807). Photos taken by Michele Esposito and www. antweb. com.

FIGURE 10. Photograph of Patagonomyrmex odoratus (Kusnezov) paralectotype alate queen: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (CASENT 0103396). Photos taken by April Nobile and www. antweb. com.

FIGURE 11. Photograph of Patagonomyrmex odoratus (Kusnezov) paralectotype male: (A) frontal view of head, (B) lateral view of body, (C) dorsal view of body (CASENT 0103405). Photos taken by April Nobile and www. antweb. com.