Bothroponera ryderae

Known from Nimba in the Guinean mountains and Mokwa in Nigeria. Bothroponera ryderae lives in forest areas that are similar to the other Bothroponera species habitat.

Identification
Joma and Mackay (2017) - A member of the Bothroponera sulcata species complex. Bothroponera ryderae has a unique suite of characters including the form of the clypeus, differences in the mandibles, eyes, body sculpture, hairs and color. The anterior medial margin of the clypeus has a single medial raised area that forms a smooth, shiny, weakly narrowed longitudinal depression, or in some specimens, is formed into a flat narrowed longitudinal strip. The mandibles are smooth and shiny, and have about 7 teeth that alternate in size. The compound eyes are relatively large, but are less projecting in the holotype and the paratypes, and slightly more projecting in the other two examined specimens. The total length is 6.55 - 7.20 mm.

The head, pronotum, propodeum, petiole and postpetiole are roughly sculptured, foveolate without punctures. The head, pronotum, propodeum, petiole, postpetiole with the 4th to 7th abdominal segments, legs and antennae are slightly or moderately shiny.

The main distinguished character of the B. ryderae worker is that the head surface is lacking erect hairs, but the pronotum, propodeum, petiole, postpetiole and 4th to 7th tergites and sternites of the abdominal segments are covered with moderately long (0.15 - 0.25 mm) erect hairs. The erect hairs are denser and slightly longer (0.20 - 0.25 mm) on the petiole, postpetiole and the 4th to 7th abdominal segments than those on the mesosoma (0.15 mm). The dorsum of the pronotum, propodeum, petiole, postpetiole and the remainder of the gastral segments are covered with scattered long erect hairs. The hairs on petiole, postpetiole and the 4th to 7th abdominal segments are denser and longer than those on the propodeum and pronotum; pygidium is covered with longer (0.30 - 0.32 mm), denser erect hairs. The entire surface is covered with fine hairs (less than 0.01 mm).

The entire body is dark brownish except for the legs, clypeus, mandibles and antennae that are brown or light brown.

Bothroponera ryderae belongs to a group of species that have a nearly vertical posteropropodeum, including Bothroponera picardi, Bothroponera silvestrii, Bothroponera soror, Bothroponera ancilla, Bothroponera pilosuperficia. The B. ryderae worker is similar to B. silvestrii in that they both lack the erect hairs on the head (except for a few on the posterior margin). It is easy to separate B. ryderae from B. silvestrii or even from the other species of the B. sulcata complex by considering the body length, the form of posteropropodeum and propodeum, the eye size and the erect hairs on top of the head.

The total length of the B. ryderae is 6.55-7.20 mm, which is larger than that of B. silvestrii. The total length of B. silvestrii is 5.25-7.05 mm, which is the smallest length in the sulcata complex. The only species that is close in total length to B. ryderae is B. silvestrii; however, this measurement overlaps in the two species.

It is easy to exclude B. silvestrii because of the form of the posteropropodeum and propodeum. In B. ryderae and B. silvestrii, the posteropropodeum is semi-vertical and sloping strongly from the posterior edge of the dorsopropodeum to the insertion point of the petiole between the propodeal lobes. The posteropropodeum is slightly concave with granulated curved lateral edges similar to those of B. picardi, B. soror, B. ancilla, and B. pilosuperficia. In contrast, the posteropropodeum in B. silvestrii slopes gradually posteriorly and forms an obtuse angle with the dorsopropodeum. The posteropropodeum is flat with weak evidence of a depressed surface and the edges are almost straight forming a sharp edge with the lateropropodeum, resembling species such as Bothroponera crassa, Bothroponera kruegeri, Bothroponera ilgii and Bothroponera notaula.

The eye length is another significant variable that can be used to separate B. ryderae and B. silvestrii. Bothroponera ryderae has a larger eye (EW 0.20-0.25, EL 0.25-0.30) than does B. silvestrii (EW 0.10-0.25. EL 0.20-0.25).

Male The head of the B. ryderae male is nearly suborbiculate, excluding the mandibles and the mouthparts. The scape is twice as long (0.20 mm length) as the pedicel (0.10 mm), shorter and thicker than the second funicular segment (0.40 mm). The clypeus is convex with a small peak that points ventrally on the lower anterior medial margin. The ocelli are relatively small. The notauli are present on the dorsum of the scutum and connect posteriorly.

The dorsopropodeum is slightly concave and gradually slopes posteriorly to reach the insertion of the petiole. The mesosomal surface is rough while the petiole and postpetiole along with 4th to 7th abdominal segments are smooth and shiny.

Fine dense silver hairs cover the entire surface. The pronotum, scutum, scutellum, propodeum, petiole and postpetiole are covered with a few short erect hairs that are scattered on the dorsum, while the head lacks erect hairs.

The entire male is yellowish.

The male of B. ryderae can be compared with the other known males of B. crassa, B. ilgii, B. silvestrii, B. notaula, B. soror and B. kruegeri in the B. sulcata species complex. Two characters are very important in recognizing males in this complex, the ocellus width and the presence or absence of notauli. The maximum diameter of the median ocellus is small in B. ryderae (0.16 mm) similar to that in males of B. ilgii (0.17 mm), B. soror (0.10-0.15 mm) and B. silvestrii (0.12-0.13 mm). In contrast, the maximum diameter of the median ocellus is large in males of B. kruegeri (0.35), B. notaula and B. crassa (0.20-0.25 mm). The notauli are presenton dorsum of the scutum of B. ryderae similar to that of B. soror, B. notaula and B. silvestrii. The notauli are not present on dorsum of the scutum of B. crassa and B. ilgii. The notauli in B. kruegeri are not distinctive, but B. kruegeri can be recognized by the large size (10.25 mm) among the other B. sulcata species complex males. The total length of B. ryderae male is 6.45 mm, which is smaller than that of both B. kruegeri (10.25 mm) and B. soror (6.45-7.45 mm), but it is larger than that of B. silvestrii (4.70-5.10 mm). Bothroponera crassa has a total length of 6.00-8.80 mm and B. notaula has a total length of 5.60-7.90 mm, which overlaps in total length with B. ryderae, but they can be easily excluded since they both have similar posteropropodeum, in contrast, the posteropropodeum in B. crassa seems to form one surface that is slightly curved and extends from dorsopropodeum to the insertion point of the petiole. The total length of the B. ilgii male is not available (without gaster), but the B. ilgii male can be recognized byhaving a slightly larger eye (0.40 width, 0.70 length) than that of B. ryderae (0.35 width, 0.60 length). The notauli are present in B. ryderae, but they are absent in B. ilgii as mentioned above.

Distribution based on Regional Taxon Lists
Afrotropical Region: Guinea, Nigeria.

Nomenclature

 *  ryderae. Bothroponera ryderae Joma & Mackay, 2017: 35, figs. 25-28, plate 12, 13, map 9 (w.m.) GUINEA.

Worker
(n=9), HL 1.30 - 1.50, HW 1.20 - 1.25, ML 0.75 -0.85, EW 0.20 - 0.25, EL 0.25 - 0.30, SL 1.05 - 1.15, FL 1.80 - 1.90, WL 2.10 - 2.25, WPL 2.65 - 2.80, PL 0.50 - 0.60, PW 0.70 - 0.75, PH 0.90 - 1.00, CI 83.33 - 92.30, OI 20.83 - 24.00, Mandl 57.69 - 56.66, SI 87.5 - 92, Peti 125 - 140. Head subquadrate; compound eyes relatively large; malar space length 0.11 - 0.15 mm, area from upper edge of eye to the upper margin of posterior lobe 0.75 mm; pronotal humerus, lower margin of pronotum and basalar sclerite rounded.

Male
(n=1), HL 0.96, HW 0.60, ML 0.22, EW 0.35, EL 0.60, SL 0.20, FL 4.35, WL 2.15, WPL 2.75, PL 0.65, PW 0.46, PH 0.70, CI 62.5, OI 100, MandI 22.91, SI 33.33, PetI 70.76. Total length 6.45 mm; eyes large, cover most of sides of head, distance between eyes 0.65 mm; medial ocellus width 0.19 mm; pronotum rounded anteriorly, straight lower lateral margin; scutellum subtriangular and elevated in lateral view; metanotum narrowed, slightly raised between dorsopropodeum and scutellum; metaepisternum well developed and separated from lateropropodeum by propodeal suture; poorly developed sulcus separating metapleuron and infra katepisternum; basalar sclerite rounded; posteropropodeum slightly concave with slightly sharp posterior lateral edges; petiole narrow, width less than propodeal width (seen from above) and height near height of propodeum and postpetiole, with bluntly rounded apex, lacking teeth on ventral process; postpetiole rounded anteriorly; head, pronotum, scutum, scutellum, propodeum, petiole roughly sculptured and postpetiole with remainder of gastral segments smooth and shiny; fine short (less than 0.02 mm) dense hairs cover entire body; entire surface lacking longer erect hairs except on margins of posteropropodeum (0.15 mm) and very few erect hairs scattered on dorsum of petiole, postpetiole (0.15 mm); 4th ot 7th gastral segments covered with very few, moderately long erect hairs (0.15-0.20 mm) denser on last two segments than other segments; color mostly pale yellow.

Type Material
Guinea: Nimba (Guinee), TG- 1300 m, Lamotte 1942, B. ryderae (1 holotype worker, 5 paratypes workers, (Holotype and 2 paratypes MNHN, one paratype Iziko, one paratype, one paratype  ), Mt To, Foret [Fôret, 8°30'0" N; 9°0'0" W], ravine, B2-41, II 1942, Lamotte (lw, paratype, MNHN), Mont to Forêt Claire [mount to woodland], (1600 m), Camp 1, II. VI. 1942, M. Lamotte, Bothroponera lamottei F. Bernard, 1950, Museum Paris EY6715 (lw, paratype, MNHN), Lamotte et Roy, VII XII 51, 39 Pa (1 w, paratype, MNHN), M. Lamotte coll., 28-X-1956, prairie eu mout a urf vers la pierre Richard, # 130pa, B. ryderae (lw MNHN).

Etymology
This species is named in honor of Dr. Suzanne Ryder, curator of the Hymenoptera collection at the Natural History Museum, London, in recognition of her outstanding support in providing specimens for this revision.

References based on Global Ant Biodiversity Informatics

 * Joma A. M. A., and W. P. MacKay. 2017. Revision of the African ants of the Bothroponera sulcata species complex (Hymenoptera: Formicidae: Ponerinae). Transactions of the American Entomological Society, 143(1): 7-71.