Rimulotilla Brothers, 2015

Brothers, Denis J., 2015, Revision of the Rhopalomutillinae (Hymenoptera, Mutillidae): 1, generic review with descriptions of three new genera, Journal of Hymenoptera Research 46, pp. 1-24 : 5-6

Rimulotilla Brothers gen. n.

Figs 3-10 , 31-32 , 39-40

Type species.

Mutilla (Rhopalomutilla) tongaana Péringuey, 1909: 386, male

Diagnosis.

MALE. Head strongly transverse with vertex dorsally produced as an angle behind ocelli in anterior view; no genal carina; mandible bidentate; scutellum almost conical with strong transverse apical tubercle; S6 with posterior margin simple; S8 weakly and evenly convex, slightly elevated posteriorly with deep median notch in posterior margin; penis valves symmetrical, each almost triangular with many long setae along posterodorsal margin; paramere without any stronger setae. FEMALE. Head slightly longer than wide in anterodorsal view; mesosoma elongate with abrupt concave narrowing between metathoracic spiracle and propodeal spiracle, lateral margins of propodeum converging posteriad; disc of propodeum posteriorly with strong transverse median tubercle (scutellar scale) and small tooth at lateral angle; metasoma strongly elongate with T1 broad and long; pygidial plate broad and poorly defined, posterior margin deeply concave between strong apical teeth.

Description.

MALE. Body black (sometimes with mesosoma partly dark red), wings entirely infuscated (sometimes hyaline basally). Head: vertex more or less evenly rounded laterally but strongly elevated behind ocelli, posterodorsal margin of head in anterior view more or less straight on each side but forming a marked angle mesally; antennal scrobe above with diagonal transverse carina and secretory tubercle; clypeus with sculptured median area, inner marginal teeth stronger than lateral teeth; genal carina absent (sometimes an irregular slight vertical ridge present), postgena slightly convex; postmandibular carina present, strong to weak; pleurostomal carina forming a ridge from posterior mandibular articulation to margin of oral fossa much anterior to half its length; mandible apically bidentate, subapical tooth smaller than apical tooth, ventral basal lamella scarcely developed. Mesosoma: mesoscutum with anteroadmedian lines weakly developed; notaulus incomplete anteriorly; parapsidal line incomplete posteriorly or complete; tegula convex, densely punctate; scutellum strongly convex, tapering posteriorly, with very strong elevated transverse tubercle; metanotal dorsellum with sides irregular but more or less straight, sculpture variable; propodeum with disc and declivity abruptly differentiated; lateral face of pronotum not strongly tapered, anteroventral margin carinate and continuous with anteroventral tooth; mesepisternum with transverse depression well developed and extending diagonally from scrobe towards ventral extremity of pronotum; mesosternum without any distinct projections. Legs: pubescence denser on tibiae and tarsi; claws deeply cleft apical to broad lamellate base; fore tibia without any apical secretory structure or with a vertically elongate preapical groove/pore on inner (anterior) surface; mid and hind tibiae with few inconspicuous preapical dorsal spines, and fewer very inconspicuous lateral spines (seldom absent). Metasoma: T2 widest posterior to midlength; T2 and S2 without any traces of lateral felt lines; pygidium (T7) with apical margin convex, edges slightly recurved (seldom not); S1 with a median tooth near base; S6 with posterior margin entire, with sparse apical fringe; hypopygium (S8) weakly convex, forming a slightly elevated lamelliform plate with deep median apical notch overlying true posterior margin, without any separate ventrally-projecting lateral lobes. Genitalia: basal ring very short; paramere almost straight with fairly broad apex, densely and finely setose on outer surface, without any differentiated strong setae; penis valves symmetrical, short, triangular, with a row of long fairly strong setae along posterodorsal margin.

FEMALE. Head: slightly elongate in anterodorsal view; sides behind eyes evenly and weakly convex, produced far beyond eye, well differentiated from posterodorsal margin of head; posterodorsal margin convex, without any distinct oblique depression at each side; clypeus with median lamellate tubercle dorsally, a median tubercle above obtusely triangular ventral concavity, a tooth at each side of concavity; gena broad, genal carina weak or absent; postmandibular carina weak and long or strong and short, separated from postgenal carina; pleurostomal carina forming a ridge from posterior mandibular articulation to margin of oral fossa; mandible more or less straight and evenly tapering distally, apically unidentate; maxillary palp unsegmented, cylindrical; labial palp two- or unsegmented, cylindrical; antennal scape with or without a weak blunt tubercle posterolaterally, flattened anteromesal surface not delimited by any carinae; pedicel without any distinct tuft of fine setae. Mesosoma: elongate, very distinctly longer than wide; anterodorsal margin distinct with short anterior face; humeral angle blunt; lateral margin fairly even and smooth, anteriorly gently rounded and weakly convex, very abruptly and strongly converging and concave to base of propodeum then almost straight to posterolateral angle with short tooth; disc of propodeum posteriorly with small tubercles on each side of strong smooth tubercle (scutellar scale) slightly overhanging margin; posterior face of propodeum nearly vertical; lateral face of pronotum with anterior oblique carina absent or scarcely indicated, a straight carina running along anteroventral margin, ventral margin straight, anteroventral extremity blunt; mesepisternum weakly and evenly convex. Legs: fore leg with femur flattened below, tibia with prominent preapical oval to arcuate secretory pore on inner (anterior) surface, tibial calcar with blade finely pectinate on margin; mid and hind femora longitudinally concave below, each with a narrow elongate preapical lamella anteroventrally; mid and hind tibiae with preapical dorsal spines strong and fairly easy to distinguish, preapical lateral spines fairly weak and moderately difficult to distinguish. Metasoma: slender; T1 with anterior face meeting dorsal face at a rounded right angle, dorsal face long, broad and somewhat transverse, almost as wide as T2, sides weakly convex and weakly diverging from base; T2 <0.75 × length T3-T6, with broad deep basal depression weakly convex posteriorly, sides beyond basal depression diverging then weakly convex and scarcely converging posteriorly, no trace of felt-line patch, posterior margin weakly concave to straight; T3 with posterior margin straight; T5 without any lateral tuft of long setae; pygidium (T6) with pygidial plate broad, with an irregular lateral bounding ridge basally, apical margin forming a semicircular concavity between two strong acute teeth; S1 with a short simple median carina anterior to a broad flat triangular area elevated anteriorly and becoming somewhat depressed posteriorly; S2-S4 with simple posterior margins; S5 with posterior margin lobed (sometimes tuberculate) on each side, with a posterolateral cluster of denser setae (sometimes without); S6 with apex acute, sides carinate, no flattened strong setae.

Species included.

Rimulotilla basalis (Bischoff, 1920), male & female?, stat. n., comb. n.; Ri. conifera (Bischoff, 1920), male & female?, comb. n.; Ri. tongaana ( Péringuey, 1909), male & female, comb. n.; two undescribed species, one male only, the other male & female.

Distribution.

Central, eastern and southern Africa (Burundi, Democratic Republic of Congo, Kenya, Malawi, Mozambique, Namibia, South Africa, Tanzania, Zambia, Zimbabwe).

Etymology.

From the Latin noun rimula, a small cleft (referring to the form of S8), combined with - tilla, a common suffix derived from the genus Mutilla ; gender feminine.

Comments.

Phoretic copulation in this genus probably has a shorter duration than in the other genera of Rhopalomutillinae since there are few recorded copulating pairs in collections and the apical sterna of the males are less modified than in the other genera. The only species for which I have seen directly associated male and female specimens (and actually collected a mating pair myself) is Ri. tongaana , hence its designation as the type species. Other sex associations have mainly been based on collection of both sexes in malaise traps at similar times and places.

Figures

Figures 3 - 10. Rimulotilla gen. n. 3 - 6 Ri. tongaana (Peringuey) 3 - 4 male, dorsal & lateral views 5 - 6 female, lateral & dorsal views 7 - 10 Ri. conifera (Bischoff) 7 - 8 male, dorsal & lateral views 9 - 10 female, lateral & dorsal views. Scales = 1 mm.

Figures 31 - 38. Rhopalomutillinae, hypopygium (S 8): left = lateral view, anterior to left; centre = ventral view, anterior to left; right = posterior view. 31 - 32 Rimulotilla gen. n. 31 Ri. tongaana (Peringuey) 32 Ri. conifera (Bischoff) 33 - 34 Pherotilla gen. n. 33 P. mlanjeana (Bischoff) 34 P. oceanica (Mickel) 35 - 37 Rhopalomutilla Andre 35 Rh. clavicornis (Andre) 36 Rh. carinaticeps Bischoff 37 Rh. anguliceps Andre 38 Bischoffiella cristata (Bingham).

Figures 39 - 46. Rhopalomutillinae, male genitalia: upper = dorsal view; middle = left volsella, exterolateral view; bottom = sagittal view, penis valves and right paramere (right volsella not shown). 39 - 40 Rimulotilla gen. n. 39 Ri. tongaana (Peringuey) 40 Ri. conifera (Bischoff) 41 - 42 Pherotilla gen. n. 41 P. mlanjeana (Bischoff) 42 P. oceanica (Mickel) 43 - 45 Rhopalomutilla Andre 43 Rh. clavicornis (Andre) 44 Rh. carinaticeps Bischoff 45 Rh. anguliceps Andre 46 Bischoffiella cristata (Bingham).