Fortuynia rotunda Marshall & Pugh, 2002

Pfingstl, Tobias, Hiruta, Shimpei F., Hagino, Wataru & Shimano, Satoshi, 2021, Juvenile morphology of seven intertidal mite species (Acari, Oribatida, Ameronothroidea) from the East Asian region, International Journal of Acarology 47 (6), pp. 536-554 : 541-543

Fortuynia rotunda Marshall & Pugh, 2002

Larva

(N = 1): length 262 µm.

Prodorsum (7B). Interlamellar and exobothridial seta minute.

Gastronotic region ( Figure 7 (b)). Eleven pairs of smooth spiniform notogastral setae; c 1-3, da, dm, dp, la, lm, lp, h 1-2. Anterior notogastral setae (50–55 µm) three times longer than posterior notogastral setae (12–15 µm). Transversal ridge on centrodorsal plate passing posterior line of setae lm and dm medially incomplete.

Podosoma and venter. Epimeral setation 2-1-2. Claparède’s organ globular, nearly completely covered by epimeral cuticle. Aggenital, genital, adanal and anal setae not developed.

Legs. Setation and solenidia see Table 3.

Protonymph

(N = 1): length 350 µm.

Gastronotic region. Fifteen pairs of simple notogastral setae; c 1-3, da, dm, dp, la, lm, lp, h 1-3, p 1-3. Anterior notogastral setae (65–70 µm) approx. twice as long as posterior notogastral setae (25–30 µm).

Podosoma and venter ( Figure 7 (c)). Epimeral setation 3-1-2-1. One pair of short genital setae (11 µm). Adanal and anal setae not developed.

Legs. Setation and solenidia are shown in Table 3.

Deutonymph unknown

Tritonymph

(N = 1): length 544 µm.

Gastronotic region ( Figure 7 (d)). Fifteen pairs of notogastral setae (30–100 µm), no conspicuous difference to protonymph.

Podosoma and venter. Epimeral setation 3-1-3-2, seta 3 c added in this stage, close to trochanter III. Four pairs of genital setae. Three pairs of adanal setae. Two pairs of anal setae, fully developed in this stage.

Legs. Large porous areas on paraxial side of each femur. Porous areas on trochanters not traceable. Setation and solenidia see Table 3.

Remarks

When Marshall and Pugh (2002) described Fortuynia rotunda from African coasts, they gave short information on the legs, e.g. colour and length of segments, and only details about the setae of genu I and II (p. 179, Figure 4 (b)). Karasawa and Aoki (2005) provided a redescription of F. rotunda based on their specimens found on the Japanese Ryukyu islands but also gave very few information about the legs, e.g. lengths of segments, smoothness of claws. Accordingly, we present herein the setation and solenidia for the legs of this species for the first time in detail and although these formulas may be the same for all Japanese F. rotunda , they may differ in the African F. rotunda . Therefore, the development of leg setation given in the present paper is so far only valid for Japanese F. rotunda .

Fortuynia rotunda is characterized by its very rounded notogaster and the juveniles already show a similar body shape with the gastronotic region being considerably broad and rounded. However, this trait should not be considered diagnostic, neither for adults nor for juveniles because it is also present in all developmental stages of F. smiti ( Pfingstl 2015) . It is further assumable that other species with similarly rounded body shapes of adults, like Fortuynia maculata , show similar rounded larva and nymphs.

Figures

Figure 4. Fortuynia shibai protonymph, left legs antiaxial view. (a) Leg I. (b) Leg II. (c) Leg III. (d) Leg IV. Scale bar valid for all legs.

Figure 7. Japanese Fortuynia juveniles.(a) F. churaumi, deutonymph ventral view.(b) F.rotunda, larva dorsal view (slightly laterally rotated).(c) F. rotunda, protonymph ventral view (distal leg segments and gnathosoma omitted). (d) F. rotunda, tritonymph dorsal view.