Myrmicaria aphidicola Calilung, 2000

Zettel, Herbert, Laciny, Alice, Balàka, Pia & General, David Emmanuel M., 2018, On the taxonomy of Myrmicaria Saunders, 1842 (Hymenoptera: Formicidae) in the Philippines, Raffles Bulletin of Zoology 66, pp. 610-623 : 611-615

Myrmicaria aphidicola Calilung, 2000

( Figs. 1–4 , 17 )

Myrmicaria aphidicola Calilung, 2000: 68 , fig. 2.

Non-type material examined. 14 workers (nest series) ( UPLB), Philippines, Mindanao Island, Davao City, Calinan Village, Malagos watershed area, coll. D.E.M. General, 04 July 2014 ; 16 workers ( CZW), Philippines, Mindanao Island, Bukidnon Province, Malaybalay, Kaamulan , 650 m a.s.l., 5–20 March ; 2 workers ( FMNH), Philippines, Mindanao Island, Davao Province, east slope Mt. McKinley , 3,000– 3,300 ft. a.s.l., coll. H. Hoogstraal, August – September 1946 .

Diagnosis (worker). In exact full-face view, eyes breaking outline of head. Scape relatively long, SI = 104–117. Anteroventral pronotal spines prominent. Sides of mesonotum weakly bulging; posterior surface with longitudinal rugae (except in small specimens). Medial carina of mesonotum not extended onto propodeum. Node of petiole moderately widened in dorsal aspect. Propodeal spines long, directed dorsocaudally, not continuing dorsal outline of propodeum. Peduncle of petiole long. Base of gaster tergite 1 with distinct striation. Specimens quite variable in size and sculptural details.

Description (worker). Measurements: min–max (n = 32): HW 1.24–1.76; HL 1.22–1.67; SL 1.41–1.83; SW 0.13–0.18; TL 5.22–7.21; Pmin 0.11–0.22; PW 0.29–0.49; PPW 0.34–0.52; SpD 0.22–0.42; PrL 0.67–0.99; FeL 1.83–2.45; ML 1.57–2.22; PnW 0.72–1.21; CI 98–109; SI 104–117; FeI 136–154.

Structures: Head ( Fig. 3 ) roundish to slightly transverse; dorsally usually with distinct reticulate rugae, but in some specimens with more prominent longitudinal rugae; laterally always with fine longitudinal rugae. Clypeus with median carina not reaching foremargin; sides with very variable longitudinal rugae, almost absent in small specimens. Mandible with sharp longitudinal rugae; apical margin with four teeth. Mesosoma with median carina on pronotum and mesonotum, posteriorly often not reaching hind margin. Pronotal dorsum usually with coarse reticulated rugae, but in few specimens with more pronounced longitudinal rugae; anteroventral teeth prominent. Mesonotum in addition to the median carina with scarce sculpture and a sharply elevated transverse carina; sides strongly, angularly elevated. Metanotal groove narrow and deep; in dorsolateral view lateral margin forming an acute angle. Sides of mesosoma with longitudinal rugae, usually reduced on sides of propodeum. Dorsum of propodeum with reduced sculpture, often with fractions of a transverse carina or of longitudinal carinae; area between bases of spines strongly concave in dorsal aspect. Propodeal spines long, directed upward in relation to anterior outline of propodeum, slightly to moderately diverging in dorsal aspect. Nodes of petiole and postpetiole rounded; peduncle of petiole long. Gaster with piliferous punctures and with fine but distinct striation at base of gaster tergite 1.

Setae abundant on trunk and appendages. Dorsal setiferation composed of two types of setae, short setae about half as long as long ones. On head dorsum, petiole and postpetiole all setae suberect. Short setae abundant on mesosoma sides, but sparse on its dorsum. On gaster, long setae suberect, short setae subdecumbent anteriorly, suberect posteriorly.

Colour (Bukidnon specimens): Trunk light to medium brown; head dorsally infuscated in few specimens, gaster variably infuscated. Antennae and legs light brown. Setae whitish.

Notes. Myrmicaria aphidicola was described from nine workers from the Mt. Apo area, Mindanao (North Cotabato Province, Kidapawan, Agco) ( Calilung, 2000). The name derives from the observed association with aphids ( Calilung, 2000). While Calilung (2000) compared M. aphidicola with M. brunnea Saunders, 1842 from India, the verbal description provides few useful characters to separate it from Philippine congeners. However, the drawings show a deep furrow behind the mesonotum, posterocaudally directed propodeal spines, and a long peduncle of the petiole.

We were not able to study types in the course of this study. However, one specimen (obviously a type, although not labelled as such) was loaned by the late Stefan Schödl (NHMW) in 2003, and at that time the first author had the chance to observe the characteristic basal striation of the gaster for a better interpretation of M. aphidicola . Unfortunately, this specimen was misplaced during the time of his severe illness and his untimely death in 2005.

Hitherto, M. aphidicola is the only described Philippine species with distinct basal striation on gaster tergite 1 ( Fig. 4 ). However, there are about three similar undescribed species ranging from southern Luzon to Leyte with the same character. Further diagnostic characters are the rather prominent anteroventral pronotal spines, a deep metanotal groove, length and direction of propodeal spines, and a long peduncle of the petiole.

RAFFLES BULLETIN OF ZOOLOGY 2018

All studied specimens from the Mt. Apo area are pale yellow, probably due to long storage in alcohol. Therefore, brown specimens from Bukidnon were used for the description of colour, which matches with the original description (compare Calilung, 2000). The Bukidnon specimens also differ from the other examined specimens by slightly larger size and longitudinal rather than reticulated rugae on the head.

Distribution. Myrmicaria aphidicola is recorded from a few localities in the central part of Mindanao. Recorded altitudes range between 630 (Kaamulan) and 1,300 m a.s.l. (Lake Agco).

Figures

Figs. 1–2. Non-type worker of Myrmicaria aphidicola from Bukidnon in lateral (1) and dorsal (2) view.

Figs. 3–4. Non-type worker of Myrmicaria aphidicola from Bukidnon: (3) head in full-face view; (4) postpetiole and base of gaster tergite 1 in dorsal view.

Figs. 17–20. Mesosoma in dorsal view: (17) Myrmicaria aphidicola from Bukidnon; (18) M. buenaventei new species (holotype); (19) M. chapmani new species (holotype); (20) M. transversa new species (holotype).