Fortuynia maledivensis, Pfingstl, Tobias, 2015

Pfingstl, Tobias, 2015, The intertidal Fortuyniidae (Acari: Oribatida): new species, morphological diversity, ecology and biogeography, Zootaxa 3957 (4), pp. 351-382 : 353-357

Fortuynia maledivensis sp. nov.

Type material. Holotype: female, 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 27.590; paratypes: NHMW 27.591.

Etymology. The specific name refers to the collection locality, the Maldives.

Diagnosis. Average length 400 µm, mean width 225 µm. Habitus typical for genus Fortuynia . Notogaster slender, oval in shape. Sensilla short, clavate, bent inwards. Prodorsal canal ci absent. Notogastral setae 14 pairs, c3 absent. Epimeral setation 3-1-3-2. Aggenital setae absent.

Description of adult. Females (N=15), length: 384–422 µm (mean 400 µm), width: 209–255 µm (mean 225 µm); no males found.

Integument. Colour dark brown. Cuticle appears shiny under dissecting microscope.

Prodorsum. Cerotegument finely granular. Cuticle dark brown laterally, median interlamellar area lighter coloured. Rostrum triangular in dorsal view, slightly projecting anteroventrally in lateral view. Whole rostrum demarcated from remainder of prodorsum by transverse ridge. Rostral setae (ro) simple, long (approx. 30 µm), lamellar setae (le) thin, shorter (approx. 20 µm). Interlamellar setae (in) minute, short,exobothridial setae (ex) fine. Bothridia small cups, orifice 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 ( Fig. 1 A). Large porose area on paraxial ventral side of femur. Chelicerae chelate, movable digit with 3 small, blunt but distinct teeth, whereas from frontal view most distal teeth split into 2 symmetrical teeth; fixed digit with 2 teeth, all teeth interlocking. Large lateral porose area from middle of chelicerae to joint of digits. Setae cha, chb approximately the same length, both dorsally slightly pectinate. Genae well sclerotized, finely granular. Distal part of each rutellum developed as thin triangular slightly curved inward membrane ( Fig. 1 B) with longitudinal incision. Setae a and m long, smooth. Mentum regular, finely granular, seta h simple and long.

Gastronotic region ( Fig. 2 A). Notogaster slender and oval in dorsal view. Cerotegument finely granular. Lenticulus more or less rectangular with irregular borders. Notogastral setae 14 pairs, thin, simple (length 16–50 µm), c1-2, da, dm, dp, la, lm, lp, h1-3, p1-3; c3 absent. Inconspicuous circular porose areas associated with bases of notogastral setae. Three pairs of single pores arranged in 2 median rows, first pair posterior to setae da, second between setae dm and dp and third posterior to dp, all hardly discernible. Five pairs of notogastral lyrifissures present; ia next to anterior border of notogaster and seta c2, im posterior of seta lm, ih laterally, ip laterad and anterior of seta p3 and ips next to p2. Orifice of opisthonotal gland gla laterally and between seta lm and lp.

Lateral aspect ( Fig. 2 C). Cerotegument finely granular, larger granules on pedotectum I and in acetabular regions. Pedotectum I present, rounded but small. Cuticular canals of van der Hammen’s organ typical for genus, whereas ce very short, only reaching anterior border of bothridium and lateral canal with posterior internal enlargement close to bothridium.

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

Legs ( Fig. 3 ). Monodactylous. Long hook-like claws. 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. Femora without ventral carinae. Large porose areas on paraxial side of femora I and II, paraxial porose areas on femora III and IV divided into dorsal and ventral part. Circular porose areas on dorsal paraxial part of trochanters 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 1.

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) thin, long, lamellar setae (le) also thin but slightly shorter. Minute exobothridial (ex) and interlamellar setae (in). Bothridia small cup-like, laterally opened. Sensilla short, clavate. On posterior border of prodorsum groups of small pores; in dorsal view sometimes difficult to detect as they are covered by anterior folds of gastronotic region. Gnathosoma no obvious differences from adult stage. Hysterosoma oval in dorsal view, slightly convex in lateral view. Centrodorsal plate with faint reticulate pattern, except for median less sclerotized area resembling inverted Y. Large folds framing centrodorsal plate, showing fine granular surface. Within certain lateral folds series of pores aligned longitudinally, leading into tracheal tubes. Orifice of opisthonotal gland gla located 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 these folds. 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.

Protonymph ( Fig. 4). (N=6): length 228–277 µm (mean 260 µm)

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

Ventral region of idiosoma. Epimeral setation 3-1-2-1. One pair of short genital setae. Adanal and anal setae not developed.

Legs ( Fig. 5 ). Chaetome and solenidia see table 1.

Deutonymph ( Figs 6 A–B). (N=4): length 316–335 µm (mean 327 µm).

Gastronotic region. Fifteen pairs of notogastral setae, same positions and shapes as in protonymph.

Ventral region of idiosoma. Epimeral setation 3-1-2-2, seta 4b added in this stage. 2 pairs of short genital setae aligned in a longitudinal row. 3 pairs of adanal setae ad1-3 flanking anal orifice. Anal setae vestigial, 2 pairs.

Legs. Chaetome and solenidia see table 1.

Tritonymph ( Figs 6 C–D). (N=5): length 372–397 µm (mean 381 µm).

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

Ventral region of idiosoma. Epimeral setation 3-1-3-2, seta 3c added in this stage, close to trochanter III. Genital setae 4 pairs, adanal setae 3 pairs (ad1-3). Anal setae fully developed, 2 pairs..

Legs. Chaetome and solenidia see table 1.

Figures

FIGURE 1. Fortuynia maledivensis sp. nov. adult. A) right pedipalp, paraxial view. B) right rutellum, ventral view.

FIGURE 2. F. maledivensis sp. nov. adult. A) dorsal view. B) ventral view. C) lateral view.

FIGURE 3. F. maledivensis sp. nov. adult left legs antiaxial view. A) leg I. B) leg II. C) leg III. D) leg IV.

FIGURE 5. F. maledivensis sp. nov. protonymph left legs, antiaxial view. A) leg I. B) leg II. C) leg III. D) leg IV.

FIGURE 6. F. maledivensis sp. nov. A) deutonymph, dorsal view. B) deutonymph, ventral view. C) tritonymph, dorsal view. D) tritonymph, ventral view.