Fortuynia rotunda, Marshall & Pugh, 2002

Marshall, David J. & Pugh, Philip J. A., 2002, Fortuynia (Acari: Oribatida: Ameronothroidea) from the marine littoral of southern Africa, Journal of Natural History 36 (2), pp. 173-183 : 176-178

Fortuynia rotunda sp. nov.

(®gures 3, 4)

Material. Three female specimens collected by D. J. Marshall, December 1997, from pneumatophores and stems of Avicennia mangroves, Bara reef, near Inhambane, Mozambique (23 ss 47 ¾S, 35ss22¾E). Holotype and two paratypes will be deposited in the Natural History Museum, London, UK.

Etymology. Speci®c name refers to the very rounded notogaster.

Idiosoma. Female 556±598 Mm long and 410±468 Mm wide. Brown; large and rounded.

Prodorsum. Surface smooth. Rostral setae smooth (69±73 Mm), lamellar setae smooth (30±44 Mm), interlamellar and exobothridial setae vestigial. Lamellar ridges absent. In dorsal aspect, bothridia partially shielded by notogastra l margin. Sensillus 14

at of by smooth, thin-walled, antero-laterally projecting and clavate. Dorsosejugal, notogastral and lateral as well as two prodorsal channels of van der Hammen’s organ present. Internal prodorsal channel (ci) short, not reaching vestiges of interlamellar setae, external prodorsal channel (ce) long, extending anteriorly across two-thirds of prodorsum, along a lateral contour.

14

at of by

Notogaster. Surface smooth. Colour brown with lighter areas anteriorly. Dorsosejugal suture complete and curved. Fourteen pairs of notogastral setae: the anterior c1, c2, da, la and lm long, other posterior notogastrals short. Separation of setae c1 greater than distance c1±c2. Setae c3 absent and vestiges not seen. Setal lengths (three individuals measured) as follows: c1 80, c2 40, la 75, lm 43, da 85. Lyri®ssures ia lateral to c2 and im between setae lm and lp. Lyri®ssures ih, ip and ips not seen. Glandular openings (gla) postero-lateral of im.

Venter. Surface smooth. Foveate plastron extends along the inner margin of coxisternum, from around acetabulum I to IV, medially along epimeral border III, and posteriorly on latero-ventral plate below notogaster. Epimeral setation typically 3-1-3-2. Epimeral setae mostly around 30 Mm long, except 1b (53±60 Mm). Coxisternum with conspicuous muscle sagillae. Sternal apodeme (medial epimeral border) disintegrates anteriorly. Transverse epimeral borders I and II (of both sides) contiguous on sternal apodeme. Genital and anal plates similar in shade to the ventral surface and epimeral plates. Genital plates trapezoid (101±105 Mm long and 70±74 Mm wide), typically bearing ®ve pairs of setae (17±20 Mm). One pair of aggenital setae. Anal plates large (134±137 Mm long and 64 Mm wide), conspicuously longer than genital plates, and each typically bearing two setae (around 20 Mm). Preanal organ large and dark. Adanal setae ad2, when present, level with lyri®ssure iad, ad3 long (30 Mm). Seta h long (66 Mm).

Legs. Femora and genua of all legs dark brown and ®nely pitted. Slight darkening of proximal and distal ends of tarsus and tibia, respectively. Lengths of femur, tibia, tarsus and claw of one individual as follows: leg I 160, 86, 55, 60; leg II 144, 74, 56, 60; leg III 90, 110, 60, 60; leg IV 150, 90, 58, 60. Tarsus III conspicuously longer and more slender and femur III remarkably shorter than these segments on other legs. Diagnostic setation of genua I and II: seta d smooth and longer than both lateral setae. Adaxial lateral l ¾, a short spine on genu I, but slightly longer on genu II. Abaxial lateral seta l ², long and barbed (®gure 4 B). Tarsi each with a single, large, open (as opposed to sharply hooked) claw, of similar length to tarsus.