Thalassozetes barbara, 2013

Pfingstl, T., 2013, Thalassozetes Barbara N. Sp. (Acari, Oribatida), A New Intertidal Species From The Coast Of Barbados, Acarologia 53 (4), pp. 417-424 : 418-423

Thalassozetes barbara n. sp.

Type locality — Barbados, Bathsheba Beach , 13°12´50´´N, 59°31´18´´W, upper eulittoral zone, Bostrychia tenella and other algae growing on rocks, 29 August 2012 .

Type specimen — Holotype: male, preserved in pure ethanol, deposition: Naturhistorisches Museum Wien, collection nr. NHMW 21887 .

Paratypes — 2 males; Barbados, Enterprise Beach near Oistins, 13°03´36´´N, 59°32´20´´W, upper eulittoral zone, diverse algae growing on rocks, 25 August 2012; deposition: Senckenberg Museum für Naturkunde Görlitz, collection Nr. 12/48679 .

Diagnosis — Dark brown sclerotized mites. Mean length 274 µm, mean width 174 µm. Cuticle of notogaster showing specific obvious reticulate pattern. Lamellar ridges conspicuous and long. A pair of short longitudinal ridges on anterior part of notogaster. Fourteen pairs of very short and blunt notogastral setae. Median depression on epimeron I present. Three pairs of genital setae. Three pairs of adanal and two pairs of anal setae. Legs monodactylous with large claw. No porose areas on femora discernable. Leg setation (trochanter to tarsus, chaetome, solenidia):

Leg I 0-3-2-3-18, 1-2-2;

leg II 0-3-2-3-15, 1-1-1;

leg III 1-2-1-2-13, 1-1-0;

leg IV 1-2-1-3-12, 0-1-0.

Description — Adult: females (n=4), length: 274 – 286 µm (mean 279 µm), width: 184 – 186 µm (mean 185 µm); males (n=7), length: 259 – 278 µm (mean 272 µm), width: 160 – 179 µm (mean 168 µm).

Integument — Colour dark brown. Cuticle of notogaster with irregular circular depressions forming a reticulate pattern. Cerotegument thick and basically granular.

Prodorsum — Cerotegument slightly granular. Rostrum rounded in dorsal view, but slightly projecting anteroventrally in lateral view. Rostrum clearly demarcated from remainder of prodorsum by a transverse ridge. Rostral setae (ro) minute, hardly discernable. Lamellar setae (le) very short and blunt, interlamellar setae (in) exiguous. One pair of minute exobothridial setae (ex). Lamellar ridges conspicuous and long, surmounting lamellar setae anteriorly. Bothridia large and thick cuticular cups, laterally opened. Sensilla clavate and short (ca. 35 – 40 µm), proximal part completely smooth, distal head densely spinose. A lighter area between bothridia reaching from lamellar ridges to dorsosejugal suture.

Gnathosoma — Pedipalp pentamerous 0-2-1-3- 9 (including solenidion) ( Fig. 1A ). Solenidion ω on palptarsus erect, not associated with eupathidium acm. Chelicerae chelate, each digit with two teeth. A large porose area on proximodorsal part of fixed digit. Seta cha and chb robust, dorsally dentate, both approximately the same length. Trägårdh’s organ normal. Rutellum triangular, distal part developed as thin curved inward membrane, medially incised ( Fig. 1B ). Seta a and m long and dentate. Mentum regular, seta h long and smooth.

Notogaster — ( Figs. 2A, 2C and 3A ). Rounded in dorsal view, convex in lateral view. Dorsosejugal suture complete but medially weakly devel- oped. Median rectangular light spot adjacent to anterior border of notogaster. Cuticle in centre of notogaster with irregular small circular depressions forming an irregular reticulate overall pattern ( Fig. 4A ). This pattern fades into a uniform granulation in lateral areas of gastronotic region ( Fig. 4B ). A pair of concave and parallel ridges on anterior part of notogaster. Laterally of these ridges, elliptical cavities showing fine granular surface. Fourteen pairs of very short and blunt notogastral setae, c 1-2, da, dm, dp, la, lm, lp, h 1-3, p 1-3 (approximate length 2 – 5µm); c 3 absent. Porose areas or distinct pores absent. Five pairs of notogastral lyrifissures present; ia next to notogastral ridges and nearly parallel to anterior notogastral border; im obliquely, next to seta c 2; lyrifissure ih next to seta lp; ips anterior to seta p 3 and ip between setae p 2 and p 1. Orifice of opisthonotal gland (gla) posterior and close to lyrifissure im.

Lateral aspect — ( Fig. 2C ). Cerotegument generally finely granular, larger granules in areas surrounding acetabula. Pedotectum I small, pedotectum II absent. Lateral parts of sejugal furrow broad and deep, showing conspicuous granules. Next to lateral border of bothridium triangular protrusion orientated caudally. Lateral enantiophyse present, anterior projection triangular, well developed, posterior protrusion triangular and small. Discidium developed as strongly projecting triangular bulge between acetabula III and IV.

Ventral region of idiosoma — ( Figs. 2B , 3B ). Cuticle basically granular, larger granules and darker colouration next to acetabula, anterior and posterior of genital orifice and laterad of anal opening. Epimeral setation 1-0-1-1, seta 1b long reaching trochanter III, setae 3b and 4a short and thin. Internal borders of all epimera well visible, sternal apodemes II, sejugal and III well developed. A densely granulated median sternal cavity on epimeron I, lateral borders slightly concave. Three pairs of short and fine genital setae, arranged in longitudinal rows. Insertion of tendon β next to anterior corners of genital orifice. Aggenital setae absent. Anal valves triangular. Preanal organ triangular in ventral view. Two pairs of short anal setae, an 1-2, arranged in a longitudinal row. Three pairs of short and simple adanal setae, ad 1-2 flanking anal orifice, ad 3 posterior of anal valves. Lyrifissure iad slightly oblique and adjacent to anterior corners of anal opening.

Legs — ( Fig. 5 ). Monodactylous. Long hook-like claws with one small proximoventral tooth. Cuticle granular, larger granules and darker colouration on all trochanters, femora and genua. Femora with slightly projecting ventral carinae. Proximal lyrifissure present on all tarsi. No porose areas on femora discernible. Antiaxial lateral seta of genu robust and blunt. Ventral setae of tarsus dentate. Famulus ε developed as a short broad knob. Solenidia ’ 1 on tibia I long and orientated backwards at base.

Etymology — The species name refers to the name of my spouse Barbara, who always supported me and my interest in research. She has tolerated my passion for the little mites for many years and moreover she accompanied me on my research trip to the beautiful island of Barbados, where the new species was found. The name is given as noun in apposition.

Figures

FIGURE 1: Thalassozetes barbara mouthparts. A – right pedipalp antiaxial view; B – right rutellum ventral view.

FIGURE 2: Thalassozetes barbara adult. A – dorsal view; B – ventral view; C – lateral view.

FIGURE 3: Thalassozetes barbara adult micrographs layered from 5-10 sequentially focused images. A – dorsal view; B – ventral view.

FIGURE 4: Thalassozetes barbara adult micrographs. A – cuticular structures on gastronotic region; B – detailed view on cuticular gastronotic structures. Scale bars = 50 µm.

FIGURE 5: Thalassozetes barbara adult legs antiaxial view. A – left leg I; B – right leg II; C – left leg III; D – left leg IV.