Fortuynia longiseta, Pfingstl, Tobias, 2015

Pfingstl, Tobias, 2015, The intertidal Fortuyniidae (Acari: Oribatida): new species, morphological diversity, ecology and biogeography, Zootaxa 3957 (4), pp. 351-382 : 357-366

Fortuynia longiseta sp. nov.

Type material. Holotype: male, Maldives, Malé atoll, Island of Villingili; 8 Feb. 1983; calcareous algae growing on sandstone; coll. W. Fiala, leg. R. Schuster. Paratypes: 2 females, same locality as holotype. Deposition of holo- and paratypes: Naturhistorisches Museum Wien/NHM Vienna, Austria; holotype: collection Nr. NHMW 27.592; paratypes: NHMW 27.593.

Etymology. Specific name refers to the very long notogastral setae shown by this species.

Diagnosis. Mean length 458 µm, mean width 254 µm. Habitus typical for the genus Fortuynia . Notogaster slender and oval in shape. Sensilla short, clavate, bent inwards. Prodorsal canal ci absent. Notogastral setae very long, 15 pairs. Epimeral setation 3-1-3-2. Aggenital setae present (1 pair).

TABLE 2. Fortuynia longiseta sp. nov. Leg setation from larva to adult. First development of setae and their homologies indicated

by letters. () = pairs of setae, - = no change with regard to preceding stage.

Instars Trochanter Femur Genu Tibia Tarsus Chaetome Solenidia

I larva - d, bv´´(l), σ (l), v´, φ (pl), (pv), s, (a), (u), (p), (tc), (ft), ε ω 0-2-2-3- 16 1-1-1 Description of adult. Females (N=4), length: 459–465 µm (mean 462 µm), width: 249–265 µm (mean 258 µm); males (N=3), length: 446–459 µm (mean 453 µm), width: 240–255 µm (mean 250 µm).

Integument. Colour dark brown, nearly black. Cuticle strongly sclerotized, appears shiny under dissecting microscope.

Prodorsum. Cerotegument finely granular. Cuticle dark brown laterally, median interlamellar area lighter. Rostrum triangular in dorsal view, slightly projecting anteroventrally in lateral view. Rostrum demarcated from remainder of prodorsum by transverse ridge. Rostral (ro) and lamellar setae (le) simple, equally long (approx. 45 µm). Interlamellar setae (in) very short, thin, exobothridial setae (ex) minute, fine. Bothridia small cups, orifice circular, narrow. Sensilla short, smooth, clavate with rounded head bent inwards.

Gnathosoma. Pedipalps pentamerous 0-2-1-3-9 (including solenidion). Solenidion ω on tarsus erect, not associated with eupathidium acm. Large porose area on paraxial ventral side of femur. Chelicerae chelate, mobile digit with 3, fixed digit with 2 teeth, all teeth interlocking. Lateral porose area from middle of chelicerae to joint of digits. Seta cha and chb dorsally slightly pectinate, both of approximately same length. Genae well sclerotized, finely granular. Distal part of each rutellum developed as thin triangular slightly curved inward membrane with longitudinal incision. Setae a and m long, smooth. Mentum regular, finely granular, seta h simple, long.

Gastronotic region ( Fig. 7 A). Notogaster slender, oval in dorsal view. Cerotegument overall finely granular. Lenticulus more or less circular with irregular borders. Notogastral setae thin, very long (length 90–120 µm), 15 pairs: c1-3, da, dm, dp, la, lm, lp, h1-3, p1-3. Inconspicuous circular porose areas associated with bases of notogastral setae; 2 pairs of single pores arranged in 2 median rows, first pair posterior and laterad of setae da, second posterior and laterad of setae dm, all hardly discernible. Posterior of seta dp located 2 groups of 5 pores. Notogastral lyrifissures 5 pairs: ia close to anterior border of notogaster, next to seta c3, im posterior of seta lm, ih next to seta h3, ip laterad and anterior of seta p3, ips next to seta p2. Orifice of opisthonotal gland gla laterally close to seta lp.

Lateral aspect ( Fig. 7 C). Cerotegument finely granular, larger granules on pedotectum I and in acetabular regions. Pedotectum I round, small. Cuticular canals of van der Hammen’s organ typical for the genus, whereas canal ce very short, only reaching anterior border of bothridium.

Ventral region of idiosoma ( Fig. 7 B). Cerotegument finely granular in sternal region; larger, densely packed granules next to acetabula. Epimeral setation 3-1-3-2, all setae simple, short. Genital setae 5 pairs, aggenital setae 1 pair. Anal valves slightly triangular, 2 pairs of long anal setae (an1-2). Preanal organ triangular. Adanal setae (an1-3) 3 pairs, simple, long; in few cases asymmetrical variation with 2 setae unilaterally. Seta ad3 on level with anterior border of anal orifice, ad2 laterad, ad1 posterior of anal valves. Lyrifissure iad orientated longitudinally, flanking anal orifice.

Legs ( Fig. 8 ). Monodactylous. Long hook-like claws with slight dorsal serration. Cerotegument finely granular. Cuticle heterogeneous, trochanters dark, proximal third of femur I and II light remainder dark, femora III and IV dark, all genua dark, all tibiae light, proximal part of all tarsi slightly darker than distal part. No ventral carinae on femora. Large porose areas on paraxial side of femora I and II, paraxial porose areas on femora III, IV divided into dorsal and ventral part. Elliptic porose areas on dorsal paraxial aspect of trochanter III and IV. All tarsi with proximal lyrifissure. Dorsal seta d on all femora slightly thickened, dorsally serrate. Ventral setae of tibiae and tarsi long, ventrally serrate. Chaetome and solenidia see table 2.

Common features of juvenile stages. Apheredermous. Colour dark brown. Integument plicate and soft, except for centrodorsal plate. Prodorsum triangular, rostrum rounded, cerotegument overall finely granular. Rostral setae (ro) and lamellar setae (le) thin, equal in length. Minute interlamellar setae (in) and exobothridial setae (ex). Bothridia small cups, laterally opened. Sensilla short, smooth, clavate. On posterior border of prodorsum, adjacent to anterior border of hysterosoma, groups of small pores. Gnathosoma shows no differences from adult stage. Hysterosoma slightly convex in lateral view, oval in dorsal view. Centrodorsal plate finely granular, except for smooth median less sclerotized area resembling inverted Y. Large folds with granular surface, framing centrodorsal plate. Within certain lateral folds, series of pores aligned longitudinally, leading into tracheal tubes. Orifice of opisthonotal gland gla situated in posterior third of lateral folds. Ventral aspect showing specific pattern of ventral folds, typical for juveniles of this genus. Pores leading into tracheal tubes aligned along ventrosejugal furrow and furrows framing genital and anal orifice. Cerotegument finely granular, slightly larger granules present in furrows and acetabular regions. Legs monodactylous with large hook-like claws. Large porose areas on the same leg segments and position as in adults.

Larva ( Fig. 9 A, B). (N=2): length 191–222 µm (mean 207 µm).

Gastronotic region. Notogastral setae slightly serrate, very long, 11 pairs: c1-3, da, dm, dp, la, lm, lp, h1-2. Circular porose areas associated with bases of notogastral setae. Transversal ridge on centrodorsal plate passing posterior line of setae lm and dm.

Ventral region of idiosoma. Epimeral setation 2-1-2. Claparède’s organ globular, nearly completely covered by epimeral cuticle; no protective seta discernible. Aggenital, genital, adanal and anal setae not developed.

Legs. Chaetome and solenidia see table 2.

Protonymph ( Fig. 9 C, D). (N=1): length 286 µm.

Gastronotic region. Notogastral setae slightly serrate, very long, 15 pairs: c1-3, da, dm, dp, la, lm, lp, h1-3, p1-3.

Ventral region of idiosoma. Epimeral setation 3-1-2-1. Seta 1c and 4a added in this stage. Genital setae short, 1 pair. Adanal and anal setae not developed. Cupule ip anterior of anal opening.

Legs. Chaetome and solenidia see table 2.

Deutonymph ( Fig. 10 A, B). (N=2): length 335–353 µm (mean 344 µm).

Gastronotic region. Notogastral setae 15 pairs, same positions and shapes as in protonymph.

Ventral region of idiosoma. Epimeral setation 3-1-2-2, seta 4b added in this stage. Genital setae short, 2 pairs; aggenital setae 1 pair, adanal setae 3 pairs, ad1-3, flanking anal orifice anal setae vestigial, 2 pairs.

Legs. Chaetome and solenidia see table 2.

Tritonymph ( Fig. 10 C, D). (N=1): length 434 µm.

Gastronotic region. Notogastral setae 15 pairs, no difference from deutonymph.

Ventral region of idiosoma. Epimeral setation 3-1-3-2, seta 3c close to trochanter III. Genital setae 4 pairs, aggenital setae 1 pair, adanal setae 3 pairs, anal setae fully developed, 2 pairs.

Legs. Chaetome and solenidia see table 2.

Figures

FIGURE 7. Fortuynia longiseta sp. nov. adult. A) dorsal view. B) ventral view. C) lateral view.

FIGURE 8. F. longiseta sp. nov. adult left legs, antiaxial view. Dorsal porose areas on femur III and IV omitted due to slightly ventral perspective. A) leg I. B) leg II. C) leg III. D) leg IV.

FIGURE 9. F. longiseta sp. nov. A) larva, dorsal view. B) larva, ventral view. C) protonymph, dorsal view. D) protonymph, ventral view.

FIGURE 10. F. longiseta sp. nov. A) deutonymph, dorsal view. B) deutonymph, ventral view. C) tritonymph, dorsal view. D) tritonymph, ventral view.