Pheidole leloi Eguchi & Bui

Katsuyuki Eguchi, Bui Tuan Viet, Emiko Oguri & Seiki Yamane, 2016, The first discovery of the “ Pheidole quadricuspis group ” in the Indo-Chinese Peninsula (Insecta: Hymenoptera: Formicidae: Myrmicinae), Revue suisse de Zoologie 123 (1), pp. 45-55 : 47-49

Pheidole leloi Eguchi & Bui , sp. n.

Figs 1-13

Type material examined: VNMN; holotype (major); Vietnam, Khanh Hoa, Hon Ba Nature Reserve, 12˚07’24”-38”N, 108˚58’24”-28”E, ca. 1030-1050 m alt.; K. Eguchi leg.; 16/iii/2013 [colony: Eg 16iii13-24]. ‒ VNMN, MCZC, MHNG, ACEG; paratypes; 8 majors, 9 minors, 1 queen from the same colony as holotype; Accession No. LC 020537 ; voucher specimen No. Ext20130410-1 (paratype) from the same colony as holotype ( ACEG).

Diagnosis: In the major, vertex as well as dorsal, lateral and ventrolateral faces of vertexal lobe strongly and coarsely reticulate; promesonotal dome with an inconspicuous transverse ridge on its posterior slope; pronotal spine almost straight; posterior slope and lateral face of the dome, mesopleuron and metapleuron irregularly rugoso-reticulate; propodeal spine somewhat digitiform, with blunt apex; ventral face of petiole with a conspicuous longitudinal carina; anterior half to two thirds of first gastral tergite finely rugoso-punctate. In the minor, posterior part of frons and vertex reticulate; mesosoma relatively densely covered with standing hairs; dorsal face of promesonotal dome weakly punctured, overlain with several rugae, and lateral face of the dome, mesopleuron, metapleuron and dorsal face of propodeum punctate; propodeal spine in lateral view elongate-triangular; petiolar node in lateral view acute at apex, and in posterior view widely and shallowly emarginate at apex.

Description

Major ( Figs 1-5 ): Body dark reddish brown with darker gaster, relatively densely covered with standing hairs ( Figs 1, 2, 4, 5 ). Head in full-face view subrectangular, with its posterior margin narrowly and shallowly emarginated medially, in lateral view relatively thick, faintly impressed on vertex; frons longitudinally rugoso-reticulate; vertex, and dorsal, lateral and ventrolateral faces of vertexal lobe strongly and coarsely reticulate; gena longitudinally rugose; frontal carina almost absent or present just as rugula(e); antennal scrobe absent; median portion of clypeus almost smooth or faintly rugose longitudinally, with a few longitudinal rugae laterally; median longitudinal carina of clypeus relatively distinct; hypostoma with a pair of stout submedian processes (“SM” in Fig. 3 ) but without median process; lateral processes of hypostoma present but tiny (“L” in Fig. 3 ); masticatory margin of mandible with apical and preapical teeth, and a tooth in front of basal angle; outer surface of mandible smooth except its base, scattering relatively long decumbent/appressed hairs; antenna with 3-segmented club; maximal diameter of eye longer than or almost as long as antennal segment X. Promesonotal dome with an inconspicuous transverse ridge on its posterior slope; pronotal spine long, slender, almost straight, with pointed apex; anterior slope of promesonotal dome largely smooth with several transverse rugae; posterior slope and lateral face of the dome, mesopleuron and metapleuron irregularly rugoso-reticulate; propodeum irregularly rugoso-reticulate dorsally, longitudinally rugose laterally, and transversely rugose posteriorly; propodeal spine somewhat digitiform, with blunt apex. Ventral surface of midcoxa and hindcoxa smooth. Petiole longer than postpetiole (excluding helcium); petiolar node in lateral view blunt at apex, in posterior view widely and shallowly emarginate at apex, in dorsal view laterally with a narrow flange; ventral face of petiole with a conspicuous longitudinal carina; postpetiole in dorsal view much broader than long, somewhat spindle-shaped; its anteroventral part forming a sharp transverse ridge. Anterior half to two thirds of first gastral tergite finely rugoso-punctate.

Holotype (major): HL, 2.36 mm; HW, 2.62 mm; SL, 1.22 mm; ML, 2.27 mm; PW, 1.18 mm; HFL 1.76 mm; PtL 0.58 mm; PtW 0.47 mm; PPtL 0.45 mm; PPtW 0.77 mm; CI, 111; SI, 46; MI, 193; HFI, 67; PtI1, 130; PtI2, 62. Paratype majors (n=8): HL, 2.39-2.49 mm, HW, 2.55-2.71 mm; SL, 1.18-1.24 mm; ML, 2.23-2.35 mm; PW, 1.16-1.20 mm; HFL, 1.74-1.80 mm; PtL, 0.61- 0.67 mm; PtW, 0.46-0.52 mm; PPtL, 0.45-0.49 mm; PPtW, 0.77-0.86 mm; CI, 107-110; SI, 45-47; MI, 188- 198; HFI, 65-68; PtI1, 128-145; PtI2, 60-63.

Minor ( Figs 6-9 ): Body dark reddish brown, relatively densely covered with standing hairs ( Figs 6, 8 , 9 ). Anteromedian part of frons largely smooth; posterior part of frons and vertex reticulate; area between antennal insertion and eye, and gena rugose; preoccipital carina conspicuous dorsally and laterally; median portion of clypeus slightly punctate, with a median longitudinal carina; masticatory margin of mandible with apical and preapical teeth followed by several small teeth; 1 or 2 small denticles between the preapical tooth and 3rd tooth; outer surface of mandible longitudinally rugose, scattered with long decumbent hairs; antenna with 3-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye shorter than antennal segment X. Promesonotal dome with a pair of spines that are long, slender and pointed apically; posterior slope of the dome with an inconspicuous transverse ridge; dorsal face of the dome weakly punctate, overlain with several rugae; lateral face of the dome, mesopleuron, metapleuron and dorsal face of propodeum punctate; propodeal spine in lateral view elongate-triangular. Petiole a little longer than postpetiole (excluding helcium); petiolar node in lateral view acute at apex, and in posterior view widely and shallowly emarginate at apex; ventral face of petiole without any process and longitudinal carina.

HL, 0.97-1.01 mm, HW, 0.89-0.93 mm; SL, 1.21- 1.27 mm; ML, 1.42-1.50 mm; PW, 0.61-0.65 mm; HFL, 1.36-1.43 mm; PtL, 0.31-0.34 mm; PtW, 0.14-0.16 mm; PPtL, 0.28-0.29 mm; PPtW, 0.31-0.34 mm; CI, 91-93; SI, 134-138; MI, 227-235; HFI, 152-155; PtI1, 111-119; PtI2, 45-49.

Queen ( Figs 10-13 ): Body dark reddish brown with dark- er gaster, relatively densely covered with standing hairs ( Figs 10 , 12, 13 ). Head in full-face view subtrapezoidal, with its posterior margin broadly and shallowly concave, in lateral view relatively thick, not impressed on vertex, with its posterior margin narrowly and shallowly emarginated medially; frons longitudinally rugoso-reticulate; vertex, and dorsal, lateral and ventrolateral faces of vertexal lobe strongly and coarsely reticulate; gena longitudinally rugose; frontal carina present just as rugula(e); antennal scrobe absent; median portion of clypeus faintly rugose longitudinally, with a few longitudinal rugae laterally; median longitudinal carina of clypeus relatively conspicuous; hypostoma with a pair of stout submedian processes but without median process; lateral processes of hypostoma present but tiny; masticatory margin of mandible with apical and preapical teeth, and a tooth in front of basal angle; outer surface of mandible smooth except its base, scattered with relatively long decumbent to appressed hairs; antenna with 3-segmented club; maximal diameter of eye longer than or almost as long as antennal segment X; median ocellus in full-face view located a little behind the level of the posterior margin of compound eye; maximum diameter of median ocellus a little longer than the distance between the median and lateral ocelli ( Fig. 11 ). Mesosoma fully segmented; pronotum almost smooth anteriorly and reticulate laterally; pronotal spine stout and straight, directing anterolaterad; mesoscutum longitudinally rugose medially and irregularly rugoso-reticulate laterally; parapsidal line weakly recognized; scuto-scutellar suture present as a deep and broad impression; mesoscutellum largely smooth dorsally; mesopleuron irregularly rugoso-reticulate, subdivid- ed into anepisternum and katepisternum; metapleuron irregularly rugoso-reticulate; propodeum longitudinally rugose laterally, and transversely rugose posteriorly; propodeal spine somewhat digitiform, with blunt apex. Ventral surface of midcoxa and hindcoxa smooth. Petiole longer than postpetiole (excluding helcium); petiolar node in lateral view blunt at apex, in posterior view widely and shallowly emarginate at apex, in dorsal view laterally with a narrow flange; ventral face of petiole with a conspicuous longitudinal carina; postpetiole in dorsal view much broader than long, somewhat spindle-shaped; its anteroventral part forming a sharp transverse ridge. Anterior three fifths of first gastral tergite finely rugoso-punctate.

HL, 2.10 mm, HW, 2.50 mm; SL, 1.21 mm; ML, 3.19 mm; MSW, 2.03 mm; HFL, 1.90 mm; PtL, 0.82 mm; PtW, 0.72 mm; PPtL, 0.60 mm; PPtW, 0.91 mm; CI, 119; SI, 48; MI, 157; HFI, 76; PtI1, 136; PtI2, 79.

Bionomics: The type series (a single colony) was collected from rotten wood on the forest floor of a relatively disturbed patch of an evergreen forest at an altitude of ca. 1,000 m.

SIMILAR SPECIES

Pheidole leloi can be morphologically well distinguished from P. quadricuspis and its named allies as follows (see also “Diagnosis” of P. leloi ).

Figures

Figs 1 - 5. Pheidole leloi sp. nov., major. (1) Head in full-face view. (2) Head in lateral view. (3) Hypostoma in ventral view: (SM) submedian processes; (L) lateral processes. (4) Mesosoma and waist in lateral view. (5) Body in dorsal view.

Figs 6 - 8. Pheidole leloi sp. nov., minor. (6) Head in full-face view. (7) Right antenna. (8) Mesosoma and waist in lateral view.

Figs 9 - 11. Pheidole leloi sp. nov. (9) Minor, mesosoma and waist in dorsal view. (10) Queen, head in full-face view. (11) Queen, ocelli.

Figs 12 - 13. Pheidole leloi sp. nov., queen. (12) Mesosoma and waist in lateral view. (13) Mesosoma and waist in dorsal view.