Oxyopomyrmex nigripes Santschi, 1907

Sebastian Salata & Lech Borowiec, 2015, A taxonomic revision of the genus Oxyopomyrmex André, 1881 (Hymenoptera: Formicidae), Zootaxa 4025 (1), pp. 1-66 : 34-40

Oxyopomyrmex nigripes Santschi, 1907 stat. nov.

( Figs. 34, 35, 36, 37, 38, 39, 40, 41, 42, 79)

Oxyopomyrmex santschii var. nigripes Santschi, 1907: 329 (w.q.m.)

Oxyopomyrmex sabulonis var. rugocciput Santschi, 1923: 326 (w.) syn. nov.

Oxyopomyrmex emeryi var. brunnescens Santschi, 1929: 147 (w.) syn. nov.

Type locality: Kairouan, Tunisia .

Type material. Oxyopomyrmex santschii var. nigripes : lectotype worker (present designation): O. Santschii | Forel | v. nigripes | Sants. | Kairounan | 1906 | (Santschi) || type || Sammlung | Dr. F. Santschi | Kairouan || ANTWEB | CASENT | 0 913249 ( NHMB) ; 4 paralectotype workers: the same data as lectotype.( NHBM) ; 3 paralectotype males: the same data as lectotype ( NHMB) .

Oxyopomyrmex sabulonis var. rugocciput : 1 worker— Oxyopomyrmex | sabulonis Sants | v. rugocciput Sants || Tunisie | El Batene | Dr. F. Santschi || Tunisie | Bathon | 6.III. 19 Dr. S. || type || Sammlung | Dr. F. Santschi | Kairounan || ANTWEB | CASENT | 0 913247 ( NHBM) .

Oxyopomyrmex emeryi var. brunnescens : 2 workers— Oxyopomyrmex | Emeryi Sants | brunnescens | Sants. | 7 SANTSCHI det. 1929 || type || T. Kairounan | Dr Normand || Sammlung | Dr. F. Santschi | Kairouan || ANTWEB | CASENT | 0 913241 ( NHBM) .

Other material examined. 1 gyne— O. Santschii | Forel | v. nigripes | Sants. | Kairounan X 0 6 | (Santschi) || Sammlung | Dr. F. Santschi | Kairouan || NHB-ONG ( NHBM) ; 1 gyne— O. Santschii | Forel | v. nigripes | Sants. | Kairounan X 0 6 | (Santschi) || Sammlung | Dr. F. Santschi | Kairouan ( NHBM) ; 8 workers— O. Santschii | Forel | v. nigripes | Sants. | Kairounan X 0 6 | (Santschi) || Sammlung | Dr. F. Santschi | Kairouan ( NHBM) .

Gyne. Redescription. Measurements (n= 2): HL: 0.743-0.782; HW: 0.737-0.771; SL: 0.447-0.475; EL: 0.246; EW: 0.156; ML: 1.194-1.255; MH: 0.748-0.77; PSL: 0.218-0.235; SDL: 0.168-0.19; PL: 0.413 - 0.413; PPL: 0.257- 0.302; PH: 0.302 - 0.302; PPH: 0.302-0.324; PNW: 0.57-0.592; TL: 0.559; TW: 0.134; PW: 0.235-0.241; PPW: 0.358-0.363; HI: 98.6-99.2; SI 1: 60.2-60.7; EI: 63.4; SI 2: 60.7-61.6; MI: 209.5 -212.0; SPI: 114.7-139.9; PI 1: 136.8 - 136.8; PI 2: 40.7-41.2; PPI 1: 79.3-100; PPI 2: 61.3-62.8; HTI 1: 72.5; HTI 2: 24.0.

Whole body dark brown, only mandibles partly pale brown, antennae brown, antennalscapes brown to pale brown at the apex, funiculus pale brown to yellowish brown. Mandibles brow to pale brown. Femora and tibiae pale brown and tarsi pale brown to yellowish brown ( Figs. 34, 35, 36).

Head quadrate, longer than wide, lateral surfaces below eyes straight, gently rounded on the posterior edges ( Fig. 36). Anterior margin of the clypeus softly convex. Eyes longitudinal, strongly narrowing downward, reaching anteroventral margin of head, 0.3 times as long as length of the head. Ocelli large. Scape short, 0.6 times as long as width of the head, at base 0.5 times as wide as in apex then gradually widened without preapical constriction. Funiculus short, 1.8 times as long as scape, first segment elongate, triangular, 2.4 times as long as wide on apex, 3.0 times as long as second segment, length ratio of segments 100: 33: 33: 33: 42: 50: 54: 75: 83: 167, apical segments 2.2 times as wide as basal segments ( Figs. 35, 36). Surface of the scape with very fine microsculpture, shiny, covered with long, dense, semierect setae.

Mesosoma 1.6 times as long as head, relatively high and robust, flat with rounded pronotal corners in profile. Scutum 0.9 times as wide as long, posterior margin regularly semicircular. Propodeum located considerably lower than mesosomal plate, propodeal spines short, triangular rising obliquely upwards, top of spine sharp directed downward or forward ( Fig. 35). Petiole sharply rounded with short peduncle, its anterior face concave, node sharply rounded on dorsal surface, posterior face slightly concave. Ventral margin of petiole straight without lobe. In dorsal view, petiole almost parallel sided before petiolar node, then gently widened. Postpetiole 0.8 times as long as wide in dorsal view, regularly widened from base to top, apical half with gently rounded sides ( Fig. 35).

Mandibles rounded with distinct longitudinally striation, shiny, inner margin with 7-8 teeth, the apical tooth massive and long. Clypeus with longitudinal striae, shiny. Frontal carinae short, extending to 1 / 3 length of eye; antennal fossa deeply impressed with striation, frontal lobes finely rugulose with thick longitudinal striae, shiny between rugosities. Frons shiny, all surface with thick longitudinal striae and finely rugulose. Area above eyes with striation and rugulose. Ventral surface of the head with striation and finely rugulose, gena shiny, with longitudinal striae ( Figs. 35, 36). Entire head bearing setae, posterior margin with sparse semierect to erect setae directed forward, lateral surfaces of the head with sparse appressed to semierect setae directed toward anterior margin, frontal area with dense, appressed to semierect setae placed transversely, directed at the center of the head, ventral surface of the head with a prominent psammophore and appressed to erect long setae. Sides of the pronotum and anepisternum shiny with sparse, distinct longitudinal striae, katepisternum shiny, smooth in central part side and apical edges with longitudinal striae, metanepisternum and metakatepisternum microreticulate with distinct longitudinal striae. Scutum smooth and shiny with a few longitudinal striae at the anterior part, posterior part shiny with sparse longitudinal striae. Scutellum smooth and shiny only outer surface with a few longitudinal striae. Metanotum punctate to rugose and dull ( Figs. 34, 35). Propodeum punctate with fine longitudinal and transverse striation in anterior half of lateral surfaces, with longitudinal striae in posterior half, shiny and smooth between them, area between propodeal spines shiny and micropunctate. Dorsal suface of propodeum rugulose to punctate, smooth and shiny between and below the spines. Dorsal suface of mesosoma on anterior half with sparse semierect to erect, long setae, anterior propodeum with a few long setae ( Figs. 34, 35). Base of petiole and postpetiole punctate on the entire surface, nodes of the petiole punctate on the top, punctate with longitudinal striae on lateral surfaces, postpetiole node punctate, sparse punctation to smooth on the top. Gaster shiny with sparse micropunctation, bearing dense, long, appressed to semierect setae.

Legs short, hind femora 0.4 times as long as mesosoma length, hind tibia 0.9 times as long as hind femora, hind tarsi 1.4 times as long as hind femora. Dorsal surface of femora with short, dense, appressed to semierect setae, inner margin with a row of dense, long, semierect setae, tibiae bearing long, appressed to semierect setae on the entire surface, inner margins with a row of semierect setae ( Fig. 35).

Male. Redescription. Measurements (n= 2): HL: 0.486-0.569; HW: 0.469-0.536; SL: 0.291-0.346; EL: 0.179; EW: 0.156; ML: 1.383-1.414; MH: 0.879-0.89; PSL: 0.193-0.201; SDL: 0.156-0.19; PL: 0.425-0.441; PPL: 0.24- 0.257; PH: 0.257 - 0.257; PPH: 0.263-0.302; PNW: 0.849 - 0.849; TL: 0.816-0.827; TW: 0.087-0.089; PW: 0.235- 0.246; PPW: 0.258-0.313; HI: 94.2-96.5; SI 1: 59.9-60.8; EI: 87.2; SI 2: 62.0- 64.6; MI: 162.9-166.6; SPI: 105.8- 123.7; PI 1: 165.4-171.6; PI 2: 27.7 -29.0; PPI 1: 79.5-97.7; PPI 2: 30.4-36.9; HTI 1: 152.2-176.3; HTI 2: 10.5-10.9.

Whole body uniformly brown. Antennal scapes pale brown to yellowish brown at the apex, funiculus first segment pale brown, segments 2-11 yellowish brown. Mandibles brown to yellowish brown. Femora and tibiae brown to pale brown, tarsi pale brown to yellowish brown ( Figs. 37, 38, 39).

Head oval, longer than wide, lateral surfaces below eyes straight, rounded on the posterior edges ( Fig. 39). Anterior margin of the clypeus straight. Eyes oval, 0.4 times as long as length of the head. Ocelli large. Antennal with 12 segments. Scape short, 0.6 times as long as width of the head, at base 0.8 times as wide as in apex, straight. Funiculus short, 2.4 times as long as scape, first segment elongate, triangular, 1.8 times as long as wide on apex, 1.7 times as long as second segment, length ratio of segments 100: 60: 55: 50: 50: 50: 60: 90: 90: 100: 175, apical segments 1.6 times as wide as basal segments ( Figs. 38, 39). Surface of the scape with very fine microsculpture, shiny, covered with short, dense, appressed to semierect setae.

Mesosoma 2.8 times as long as head, relatively high and robust, very feeble convex in profile with rounded pronotal corners. Scutum 1.1 times as wide as long, posterior margin regularly semicircular. Propodeum located considerably lower than mesosomal plate, propodeal spines lobe-like, short ( Fig. 38). Petiole rounded with long peduncle, its anterior face slightly concave, node sharply rounded with slightly cavity in the central part and two small nodules at the outer edges, posterior face strongly concave. Ventral margin of petiole straight without lobe. Postpetiole in profile regularly rounded. Postpetiole regularly widened from base to top in dorsal view, apical half with gently rounded sides ( Fig. 37, 38).

Mandibles elongate with longitudinally striation, shiny, inner margin with 4-5 teeth, the apical tooth massive and long. Clypeus rugulose but shiny. Frontal carinae curve outward to merge with the rugae surrounding antennal sockets, antennal fossa impressed, shiny and rugulose, frontal lobes rugulose with thin longitudinal striae, shiny between rugosities. Frons rugulose with longitudinal striae, area above eyes and ventral surface of the head rugulose with longitudinal or transverse striation, gena rugulose with longitudinal striae ( Fig. 39). Entire head bearing setae, posterior margin with dense, very long semierect to erect setae directed forward, lateral surfaces of the head with dense, long, semierect setae directed toward anterior margin, frontal area with dense, semierect to erect, long setae placed transversely, directed toward center of the head, ventral surface of the head with appressed to semierect long setae. Sides of the pronotum punctate to rugulose with a thin and fine longitudinal striae, anepisternum smooth and shiny with slight microstriation, katepisternum smooth to microreticulate with slight longitudinal microstriation, metanepisternum and metakatepisternum rugulose with longitudinal striae. Scutum rugulose with slight and thin longitudinal striae except three longitudinal stripes located at the centre and outer edges of the scutum which are smooth and shiny with sparse, very weak longitudinal striae. Central stripe wide, narrowing toward centre, reach only half of the length of the scutum. Scutellum with thin longitudinal striae ( Figs. 37, 38). Propodeum punctate with longitudinal striae on lateral surfaces, area between propodeal spines shiny and smooth. Dorsal suface of propodeum punctate with longitudinal striae, punctate to smooth and shiny between and below the spines. Dorsal suface of mesosoma with sparse, long, erect setae on anterior half, anterior propodeum without setae. Base of petiole and postpetiole on the entire surface punctate, nodes of the petiole punctate on lateral surfaces, dorsal surface of the petiole node punctate, back side with a few longitudinal striae, postpetiole node punctate, on the top punctate to micropunctate, shiny. Gaster shiny with microreticulation, bearing sparse, long, semierect to erect setae ( Figs. 37, 38).

Legs short, hind femora 0.7 times as long as mesosoma length, hind tibia 0.9 times as long as hind femora, hind tarsi 1.6 times as long as hind femora. Dorsal surface of femora with several, short, semierect setae, inner margin with a row of the sparse, semierect setae, tibiae bearing long, semierect setae on the entire surface, inner margins with a row of semierect setae ( Fig. 38).

Worker. Redescription. Measurements (n= 15): HL: 0.678 ± 0.023 (0.636-0.704); HW: 0.658 ± 0.02 (0.626- 0.693); SL: 0.452 ± 0.021 (0.413-0.48); EL: 0.231 ± 0.008 (0.223-0.246); EW: 0.122 ± 0.007 (0.112-0.134); ML: 0.785 ± 0.035 (0.743-0.849); PSL: 0.159 ± 0.004 (0.151-0.162); SDL: 0.116 ± 0.004 (0.112-0.123); PL: 0.303 ± 0.016 (0.274-0.324); PPL: 0.217 ± 0.014 (0.201-0.246); PH: 0.226 ± 0.013 (0.201-0.246); PPH: 0.226 ± 0.012 (0.212-0.246); PNW: 0.431 ± 0.015 (0.413-0.458); TL: 0.467 ± 0.02 (0.444-0.503); TW: 0.097 ± 0.007 (0.084- 0.103); PW: 0.184 ± 0.009 (0.168-0.201); PPW: 0.261 ± 0.01 (0.243-0.279); HI: 97.1 ± 1.4 (95.7-99.1); SI 1: 66.1 ± 1.4 (64.2-68.2); EI: 52.9 ± 3.6 (49.8-60.1); SI 2: 68.3 ± 1.3 (66.0-70.0); MI: 182.1 ± 2.0 (179.4-185.4); SPI: 136.2 ± 4.6 (126.8 -142.0); PI 1: 134.3 ± 6.7 (125.4-148.6); PI 2: 42.6 ± 1.6 (40.7-45.3); PPI 1: 96.1 ± 3.7 (90.2 -100.0); PPI 2: 60.5 ± 1.5 (57.6-62.2); HTI 1: 71.8 ± 2.0 (69.5-75.1); HTI 2: 20.7 ± 1.1 (18.9-22.1).

Head, thorax and abdomen from dark brown to brown. Antennal scapes pale brown, apex of the scapes and funiculus yellowish-brown. Femora pale brown, tibiae and tarsi yellowish brown ( Figs. 40, 41, 42).

Head rectangular, longer than wide lateral surfaces below eyes straight, slightly rounded on the posterior edges ( Fig. 42). Anterior margin of the clypeus smooth and straight. Eyes longitudinal, strongly narrowing downward, reaching anteroventral margin of head, 0.3 times as long as length of the head. Scape short, 0.7 times as long as width of the head, at base 0.6 times as wide as in apex, gradually widened, slightly bent downward. Funiculus short, 1.5 times as long as scape, first segment elongate, triangular, 1.8 times as long as wide on apex, 3.5 times as long as second segment, length ratio of segments 100: 29: 29: 29: 29: 33: 33: 67: 86: 143, apical segments 1.4 times as wide as basal segments ( Figs. 41, 42). Surface of the scape with very fine microsculpture, shiny, covered with short and appressed setae.

Promesonotum 1.1 times as long as wide, flat in profile. Promesonotal suture distinct, the border between dorsal and posterior surfaces of the promesonotum smoothly curved in profile view. Propodeum quadrate, 0.9 times as long as wide, propodeal spines very short, triangular, the upper edge parallel to the dorsal surface of propodeum, only peaks of spines gently raised ( Fig. 41). Petiole rounded with short peduncle, its anterior face straight, node sharply rounded on dorsal surface in profile. Posterior face straight. Ventral margin of petiole straight and smooth ( Fig. 41). Postpetiole regularly rounded in profile. Postpetiole 0.8 times as long as wide in dorsal view, regularly widened from base to top, apical half with gently rounded sides ( Figs. 40, 41).

Mandibles rounded, with outer and dorsal edges straight and smooth, inner margin with 7-8 teeth, the apical tooth massive and slightly longer then the rest of teeth. Clypeus on entire surface smooth and shiny. Frontal carinae short, extending to upper edge of the antennal fossa; antennal fossa deeply impressed, microreticulate, frontal lobes rugulose with thick longitudinal striae, shiny. Frons shiny, all surface with thick longitudinal striae and rugulose. Area above eyes shiny with thick longitudinal striae and slightly rugosity. Ventral surface of the head with distinct striation and rugulose, gena shiny with striation and rugosity ( Figs. 41, 42). Entire head bearing setae, posterior margin with sparse erect setae directed forward, lateral surfaces of the head with appressed to semierect setae directed toward anterior margin, frontal area with appressed to semierect setae placed transversely, directed to the center of the head, ventral surface of the head with a prominent psammophore and appressed to erect long setae. Pronotum dull, rugose with longitudinal striae, rounded in the edges, lateral surfaces punctate with distinct longitudinal striae. Dorsal suface of pronotum rugose with sparse longitudinal and vertical striation, lateral surfaces punctate with distinct longitudinal striae. Mesonotum with longitudinal striae on the top, lateral surfaces punctate with longitudinal striae, dorsal surface of propodeum punctate to smooth and shiny, punctate with longitudinal striae below spiracles ( Figs. 40, 41, 79). Dorsal suface of mesosoma with at least two setae on anterior half, mesonotum and anterior propodeum with a few setae. Base of petiole and postpetiole on the entire surface punctate, nodes punctate, punctate with fine longitudinal striae on the top, covered with several setae. Gaster shiny and smooth, bearing sparse, erect setae.

Legs short, hind femora 0.7 times as long as mesosoma length, hind tibia 0.8 times as long as hind femora, hind tarsi 1.5 times as long as hind femora. Dorsal surface of femora with short, sparse, appressed pubescence, inner margin with a row of the sparse, short, appressed pubescence, tibiae bearing long, semierect setae on the entire surface, inner margins with a row semierect setae ( Fig. 41).

Biological data. Santschi (1907) reported nests as occurring in clay soil and having round entrances surrounded by a crater, which sometimes, especially after rain, could become cylindrical.

Distribution. Tunisia.

Differential diagnosis. Gyne. Oxyopomyrmex nigripes belongs to a group of species with rugulose genae. In this group, it is clearly distinguished from O. oculatus by striae covering the entire gena, lack of oblique striae on the frons and presence of smooth and shiny sculpture on dorsal surface of postpetiolar node.

Male. Oxyopomyrmex nigripes is distinguished from O. oculatus by lacking punctation on the scutum and scutellum; from O. insularis by the presence of transverse striation on the dorsal surface of its head; from O. magnus , O. krueperi and O. saulcyi by the lack of rugosity or smooth sculpture on the scutellum and from O. emeryi by the presence of propodeal spines.

Worker. Oxyopomyrmex nigripes belongs to a group of species that has longitudinal striae covering the entire surface of the head. It is easy to distinguish from O. polybotesi , O. pygmalioni and O. negevensis by the lack of punctation on the dorsal surface of the pronotum, paler colouration and a flat promesonotum in dorsal profile view; from O. krueperi it is distinguished by the lack of a sharply curving border between dorsal and posterior surfaces of the promesonotum, the flat promesonotum (in profile view), the distinct striation and rugosity on the dorsal and lateral surfaces of the pronotum and the paler colouration; from O. laevibus it is distinguished by longitudinal striae on the posterior margin of the head, the flat promesonotum (in profile view), the paler colouration and the distinct rugosity and striation on the thorax. At first glance O. nigripes is very similar to O. saulcyi . Both of these species have pale colouration and the promesonotum is flat in profile view. Oxyopomyrmex nigripes differs from O. saulcyi by having a distinct striae covering the entire dorsal surface of the pronotum and by the lateral surfaces of the pronotum always bearing thick longitudinal striae and rugosity. In contrast, O. saulcyi has the dorsal surface of the pronotum distinctly rugulose and striae, if present, cover only part of it; the lateral surfaces of the pronotum are more rugulose with a thin and slightly striation. In addition to these features O. nigripes has a wider head: the HI: 97.1 ± 1.4 (95.7-99.1) vs. 92.8 ± 2.1 (87.5-96.5) and the propodeum and its scape are longer: SI 2: 68.3 ± 1.3 (66.0- 70.0) vs. 73.2 ± 1.7 (70.1-77.4).

Comments: Having examined of all type specimens of Oxyopomyrmex santschii var. nigripes Santschi, 1907 , Oxyopomyrmex sabulonis var. rugocciput Santschi, 1923 and Oxyopomyrmex emeryi var. brunnescens Santschi, 1929 significant differences between these taxa were not found. The sculpture of the head and thorax and the body colouration are very similar in all. Also, examination of measurements and indices did not reveal any significant differences. All these features enabled us to synonymize Oxyopomyrmex sabulonis var. rugocciput and Oxyopomyrmex emeryi var. brunnescens with Oxyopomyrmex nigripes .