Pheidole dodo, FISCHER, G. & FISHER, B. L., 2013

FISCHER, G. & FISHER, B. L., 2013, A revision of Pheidole Westwood (Hymenoptera: Formicidae) in the islands of the Southwest Indian Ocean and designation of a neotype for the invasive Pheidole megacephala, Zootaxa 3683 (4), pp. 301-356 : 319-322

Pheidole dodo sp. n.

( Figs. 16A–F )

Holotype: (major worker), MAURITUS, Cocotte Mt. , 20.4413 S, 57.4728 E, 700 m, rainforest, sifted leaf litter, collection code BLF12091, 28.v.2005 (B.L. Fisher et al.) ( CASC: CASENT0060617 ).

Paratypes: (1 major & 6 minor workers) same data as holotype ( CASC: CASENT0060618 – CASENT0060624 ); (2 major & 12 minor workers) Cocotte Mt. , 20.4413 S, 57.4728 E, 700 m, rainforest, under moss, above ground, collection code BLF12092–BLF12094, 28.v.2005 (B.L. Fisher et al.) ( CASC: CASENT0059736 – CASENT0059749 ); (2 major & 5 minor workers) Cocotte Mt. , 20.4413 S, 57.4728 E, 700 m, rainforest, under moss, on rotten log, collection code BLF12105, 28.v.2005 (B.L. Fisher et al.) ( CASC: CASENT0059722 , CASENT0059724 – CASENT0059727 ); (3 major & 6 minor worker) Cocotte Mt. , 20.4413 S, 57.4728 E, 700 m, rainforest, ex rotten log, collection code BLF12103, BLF12111, 28.v.2005 (B.L. Fisher et al.) ( BMNH: CASENT0059717 ; CASC: CASENT0059699 – CASENT0059701 , CASENT0059716 , CASENT0059718 – CASENT0059721 ; MCZC: CASENT0059696 , MHNG: CASENT0059697 ; SAMC: CASENT0059698 ) .

Diagnosis: Relatively small species (WL major 0.70–0.87, WL minor 0.55–0.62) with relatively short scapes (SI major 48–52, SI minor 97–107) and legs (FI major 60–66, FI minor 100–107), longer standing hairs and shorter pilosity on mesosoma relatively rare. Major head anteriorly longitudinally rugose, posterior 1/3 to 1/5 of face smooth and shiny, hypostomal margin with conspicuous submedian teeth, median process wide, postpetiole in profile with small to very conspicuous triangular ventral process. Minor head longer than wide (CI 88–93), mandibles longitudinally striate, propodeal spines moderately long (PSLI 18–22), punctures in face and most of mesosoma weak to superficial, with smooth and shiny areas on posterior head dorsum, as well as on dorso- and lateropronotum, postpetiole on average as high as long (LPpI 91–115).

Description of major workers: Measurements (holotype): HW 0.98, HL 1.01, SL 0.47, MDL 0.54, EL 0.13, WL 0.81, PNH 0.37, PNW 0.50, MNH 0.56, PDH 0.29, PTL 0.35, PPL 0.16, PTH 0.23, PPH 0.22, PTW 0.16, PPW 0.26, PSL 0.15, MFL 0.63, MTL 0.47, CI 97, SI 48, MDI 55, EI 13, FI 64, PSLI 15, LPpI 74, DPpI 163, PpWI 163, PpLI 46, PpHI 96.

Measurements (n=6): HW 0.93–1.03 (0.96), HL 0.93–1.03 (0.97), SL 0.46–0.50 (0.48), MDL 0.48–0.57 (0.53), EL 0.12–0.14 (0.13), WL 0.70–0.87 (0.79), PNH 0.32–0.42 (0.37), PNW 0.45–0.53 (0.49), MNH 0.49–0.57 (0.54), PDH 0.22–0.30 (0.28), PTL 0.31–0.35 (0.33), PPL 0.15–0.17 (0.16), PTH 0.19–0.22 (0.21), PPH 0.19–0.21 (0.20), PTW 0.16–0.17 (0.17), PPW 0.23–0.26 (0.25), PSL 0.13–0.16 (0.15), MFL 0.59–0.64 (0.62), MTL 0.42– 0.46 (0.45), CI 97–101 (100), SI 48–52 (50), MDI 51–56 (55), EI 12–15 (13), FI 60–66 (64), PSLI 14–16 (15), LPpI 76–85 (81), DPpI 150–156 (154), PpWI 135–153 (148), PpLI 46–50 (48), PpHI 90–100 (95).

Head as long as wide (CI 97–101), sides in full-face view weakly convex and subparallel, posterior emargination moderately shallow. Mandibles smooth and shiny and of moderate length (MDI 51–56). Clypeus smooth with median carina short or absent and one or two pairs of lateral carinae. Frons and sides of head longitudinally rugose, interspaces smooth to superficially punctate at frons, punctate or weakly punctate at sides, in profile view rugae at the sides dorsal and ventral of eyes in some specimens, in others ending shortly after anterior half of the head and reaching further toward posterolateral corners. In full-face view, posterior 1/3 to 1/5 of face smooth and shiny. Frontal carinae very short or inconspicuous, antennal scrobe absent. Scapes relatively short (SI 48–52), pilosity decumbent. Submedian hypostomal teeth conspicuous, median process comparatively wide. Promesonotum in profile convex, promesonotal process only weakly produced, with sometimes shallowly convex, sometimes inconspicuous, transverse groove, posterior declivity low and steeply declining toward narrow, barely or not impressed metanotal groove, the latter with few superficially developed cross-ribs. Surface of promesonotum and lateropronotum mostly smooth to superficially punctate, sometimes with few short, superficial, transverse rugulae dorsolaterally, sometimes with stronger and longer rugulae anteriorly, remainder of mesosoma largely smooth to weakly punctate, with smooth and shiny area on katepisternum. Spines short, subtriangular in profile (PSLI 14–16). Metafemur relatively short (FI 60–66), metatibia on inner edge with decumbent pilosity, on outer edge with suberect to subdecumbent pilosity. Postpetiole in profile higher than long (LPpI 74–85), with small triangular ventral process, in dorsal view trapezoidally shaped and about 1.5 times wider than petiole (PpWI 135– 163). Dorsum of petiole and postpetiole smooth, remainder weakly punctate. Gaster smooth. Amount and length of standing hairs on body dorsum variable, usually with few long hairs and some shorter hairs in between, some of them with blunt or bifurcate apices. Fine, short pilosity slightly more abundant. Color orange to dark orange, gaster usually darker.

Description of minor workers: Measurements (n=11): HW 0.44–0.48 (0.46), HL 0.48–0.53 (0.51), SL 0.44– 0.48 (0.46), MDL 0.29–0.32 (0.30), EL 0.09–0.10 (0.10), WL 0.55–0.62 (0.59), PNH 0.21–0.24 (0.23), PNW 0.29–0.32 (0.30), MNH 0.29–0.41 (0.36), PDH 0.19–0.21 (0.20), PTL 0.19–0.24 (0.22), PPL 0.10–0.12 (0.11), PTH 0.12–0.13 (0.11), PPH 0.10–0.11 (0.10), PTW 0.08–0.10 (0.09), PPW 0.12–0.15 (0.13), PSL 0.08–0.10 (0.09), MFL 0.45–0.50 (0.47), MTL 0.32–0.36 (0.34), CI 88–93 (91), SI 97–107 (100), MDI 60–70 (65), EI 18–22 (21), FI 100–107 (102), PSLI 18–22 (19), LPpI 91–115 (102), DPpI 113–132 (120), PpWI 139–156 (146), PpLI 42–54 (49), PpHI 77–85 (81).

Head subrectangular, longer than wide (CI 88–93), sides convex, posterior head margin medially weakly concave, occipital carina almost invisible in full-face view. Mandibles relatively short (MDI 60–70), longitudinally striate. Clypeus smooth, with short, sometimes weakly developed, median carina, and lateral carinae inconspicuous. Face punctate to weakly punctate, punctures often overlain with faint longitudinal rugulae, posterior head margin in full-face and oblique dorsal view usually superficially sculptured to smooth. Scapes short (SI 97–107), when laid back surpassing posterior head margin by slightly less than length of ninth funicular segment, pilosity decumbent to subdecumbent. Promesonotal outline in profile convex, somewhat elongated, slightly rounded at posterior declivity. Metanotal groove narrow, barely impressed, with short, superficial crossribs. Promesonotum dorsally superficially punctate to smooth, lateropronotum medially with large smooth area, rest of mesosoma punctate to superficially punctate. Propodeal spines acute, elongate-triangular, moderately long, but shorter than distance between their bases (PSLI 18–22). Metafemur short (FI 100–107), metatibia with decumbent to subdecumbent pilosity. Postpetiole distinctly higher than long (LPpI 74–85), ventral process absent or inconspicuous, petiole and postpetiole dorsally smooth, remainder weakly punctate. Gaster smooth and shiny. Standing hairs relatively rare, stiff, and of medium length, with one longer pair on pronotum, several hairs branched subapically, shorter pilosity decumbent and slightly more abundant. Color dark brown, mandibles and appendages slightly lighter.

Discussion: Pheidole dodo is known from Mauritius only, where it was collected from the ground, inside rotten logs, under moss or from the leaf litter and in coastal scrub, closed vegetation, low closed forest, disturbed and undisturbed rainforest, in elevations between 1 and 760 m. The minors are most similar to those of P. braueri , differing from the latter by slightly smaller eyes (EI 18–22, mean 21, versus EI 22–24, mean 24) and decumbent to subdecumbent versus mostly suberect scape pilosity in P. braueri . The majors look like an odd hybrid of those of P. braueri , P. jonas , and P. decepticon , with the head in full-face view somewhat resembling that of P. decepticon , the mesosoma in profile similar to P. jonas and the postpetiole shape closest to P. braueri . This combination, however, makes this species unique and easily identifiable on the islands of the Malagasy region.

Etymology: The species is named after the iconic and extinct endemic bird of Mauritius – the Dodo, which has become somewhat symbolic for the accelerated number of human caused extinctions. The name is a noun in apposition and thus invariable.

Additional material examined: MAURITIUS: Bassin Blanc, 20.45 S, 57.466709 E, 500 m, disturbed rainforest, 06.v.1989 (P.S. Ward); Bassin Blanc, 20.4532 S, 57.4777 E, 480 m, rainforest, 29.v.2005 (B.L. Fisher et al.); Ile aux Aigrettes, 20.4188 S, 57.7305 E, 1 m, coastal scrub, 28.v.2005 (B.L. Fisher et al.); Le Pouce, 20.2 S, 57.5167 E, 700 m, low closed forest, 09.iv.1989 (P.S. Ward); Le Pouce Mt., Moka Range, 20.1985 S, 57.529 E, 750 m, closed vegetation, 25.v.2005 (B.L. Fisher et al.); Mgne. Cocotte, 20.4333 S, 57.4667 E, 760 m, disturbed rainforest, 06.v.1989 (P.S. Ward); Mt. Cocotte , 20.4414 S, 57.4722 E, 743 m, litter, 08.iv.2005 / 25.viii.2005 (L. Lach); Petite Rivière Noire Mt., 20.4088 S, 57.4077 E, 750 m, rainforest, 29.v.2005 (B.L. Fisher et al.) .

Figures

FIGURE 16 Pheidole dodo sp. n., full-face view (A), profile (B), and dorsal view (C) of paratype minor worker (CASENT0060619) and full-face view (D), profile (E), and dorsal view (F) of holotype major worker (CASENT0060617).