Galumna natalensis Jacot, 1940

Ermilov, Sergey G. & Hugo-Coetzee, Elizabeth A., 2019, Redescriptions and species status of the South African mites Galumna lawrencei Jacot, 1940 and Galumna natalensis Jacot, 1940 (Acari, Oribatida, Galumnidae), with lectotype designation, Zootaxa 4568 (3), pp. 581-586 : 582-586

Galumna natalensis Jacot, 1940

( Figs 1B ; 2C, D ; 3 C, D )

Diagnosis. Body length: 1145; notogaster width: 929, measurements of length and width of two available specimens were not possible. Body color dark brown. Body surface densely microgranulate (visible under high magnification). Prodorsum with several short longitudinal striae laterobasally. Rostrum rounded. Lamellar and sublamellar lines thin, slightly divergent mediodistally, L directed to lateral sides of prodorsum, S curving backwards at ventral ends. Rostral and lamellar setae approximately similar in length, long, setiform, roughened. Interlamellar setae represented by alveoli. Bothridial setae long, setiform, smooth. Sejugal porose areas elongate oval, transversely oriented, located posterior to interlamellar setae. Dorsophragmata distinctly elongated. Dorsosejugal suture present, simple. With 10 pairs of setal alveoli and five pairs of porose areas, Aa elongate oval, transversely oriented, distanced from pteromorphal hinges, located between la and lm, slightly closer to lm, others (A1, A2a, A2b, A3) oval. Median pore represented by cluster of several small pores between A2a in males (unknown for females). Lyrifissures im located between Aa and A1. Opisthonotal gland openings located lateral to A1. Six pairs of epimeral setae observed. Epimeral, genital, aggenital, anal and adanal setae short, setiform, thin, roughened. Anterior edge of genital plates with two setae, but third pair located close to edge. Aggenital setae inserted closer to genital plates than to anal plates. Circumpedal carinae long, reaching epimere I. Adanal lyrifissures located close and slightly diagonal to anal plates. Adanal setae ad 1 and ad 2 posterior, ad 3 lateral to anal plates. Distance ad 1 – ad 2 shorter than ad 2 – ad 3. Presence or absence of postanal porose area not determined. Median claw of legs distinctly thicker than laterals, all slightly barbed on dorsal side. Famulus on tarsi I inserted slightly anterolateral to solenidion ω 1. Solenidion inserted in anterior part of tibiae IV.

Remarks. (1) Berlese’s original description ( Berlese 1916, pp. 55–56) of G. maxima (now Galumna inquirenda Subias, 2018 ; see above) was very brief (figures absent), and Jacot did not study the type material of this species personally, so the basis for his proposal of two subspecies seems weak. Mahunka & Mahunka-Papp (1995) reported that G. maxima was absent from Berlese’s collection, and considered it a “species non interpretabiles.”

Both of these taxa were collected from the general area of Pietermaritzburg, and it seems unlikely that they could maintain distinctness in sympatry, without reproductive isolation, i.e. without being separate species. Also, G. maxima lawrencei and G. maxima natalensis are morphologically distinct. They differ, e.g., in: the direction of lamellar lines; the morphology of bothridial setae, notogastral porose areas Aa, and the median pore in males; the length of circumpedal carinae; and the number of notogastral porose areas and epimeral setae. Despite its short description, G. maxima appears to differ from each South African species in morphological traits that are widely used in identification of galumnid mites at the species level: from G. lawrencei by its rounded notogastral porose areas Aa (versus distinctly elongate triangular) and much larger body size (1100 × 800 versus 680–747 × 514–547); from G. natalensis by the barbed bothridial setae (versus smooth), rounded notogastral porose areas Aa (versus distinctly elongate oval) and four pairs of notogastral porose areas (versus five pairs).

(2) Jacot (1940) described Galumna maxima lawrencei based on 10 specimens, but our investigation of the type material showed that one specimen is Pergalumna sp. (marked by us with red color on the slide and designated with letter “X” on Fig. 1A ). Thus, the cotype series is a mixture of two species, and a lectotype designation is warranted to ensure stability in zoological nomenclature, according to the International Code of Zoological Nomenclature (Article 74 and recommendation 74G). We hereby designate the lectotype of G. lawrencei as the specimen designated with an arrow on Fig. 1A , and indicated by a semi-oval black line on the cotype slide; all other nine specimens, including the Pergalumna sp., have the required designation of paralectotype.

Figures

FIGURE 1. Photograph of slides containing respective cotype series (all adults) of Galumna maxima lawrencei Jacot, 1940 (A) and Galumna maxima natalensis Jacot, 1940 (B). L—lectotype of G. m. lawrencei, X—specimen of Pergalumna sp.

FIGURE 2. Images of Galumna lawrencei Jacot, 1940 (A, B) and Galumna natalensis Jacot, 1940 (C, D), adults: A, C—dorsal view; B, D—ventral view.

FIGURE 3. Galumna lawrencei Jacot, 1940 (A, B) and Galumna natalensis Jacot, 1940 (C, D), adults: A, C (lamellar setae broken)—dorsal view; B, D (some genital, adanal and many epimeral setae broken)—ventral view, left half (legs not shown). Scale bar 100 µm (A, B), scale bar 200 µm (C, D).