Lagoenaxonopsalbia Pešić & Smit, 2018

Pešić, Vladimir, Smit, Harry & Mary, Nathalie, 2018, Fifth contribution to the knowledge of water mites (Acari: Hydrachnidia) from the Comoros: a checklist and description of one new genus and four new species, Zootaxa 4483 (2), pp. 331-348 : 339-340

Lagoenaxonopsalbia Pešić & Smit gen. nov.

Diagnosis. Characters of Axonopsalbia -like mites as given by Cook (1974): Dorsal and ventral shields fused posteriorly; lateroglandularia fused with dorsal shield; two pairs of glandular platelets located near the anterior margin of ventral shield, no glandularia in the dorsal furrow; tips of Cx-I not extending to frontal idiosoma margin; Cx-IV with two pairs of glandularia, one located immediately medial, the other posterior to IV-L-insertions; projections associated with openings of IV-L-insertions relatively long and bluntly pointed; three pairs of genital acetabula. Male: Posterior end of dorsal shield modified as illustrated in Fig. 6A , forming a well developed axeshaped cauda; excretory pore on a separate plate lying on the caudal portion of the dorsal shield, excretory pore plate more elevated in the centre, almost circular in lateral view, with paired groups of long setae flanking the excretory pore and paired glandularia associated with humps. Female: Excretory pore lying at extreme end of dorsal shield ( Fig. 7A ); acetabula-bearing plates and postgenital sclerite fused with the dorsal shield; a pair of glandularia near the anterior margins of the acetabula-bearing genital plates fused to the ventral shield ( Fig. 7B ).

Type species: Lagoenaxonopsalbia comorosensis sp. nov.

Remarks. The combination of a well developed flask-shaped idiosoma with a large, widened cauda, the genital field with the gonopore located in terminal position on the cauda, flanked by three pairs of acetabula, and the excretory pore plate elevated in the centre and almost circular in lateral view, lying on the caudal portion of the dorsal shield, will easily distinguish the male of the new genus.

The combination of relatively long projections associated with the openings of IV-L-insertions, the acetabulabearing plates fused with the postgenital sclerite and the presence of a pair of glandularia medially to the insertions of IV-L, makes the female of the new species most similar to Axonopsalbia K. Viets, 1913 and Pseudaxonopsalbia (Motasaxona) Cook, 1974 . The females of the latter two taxa can be distinguished from the new species in: 1) dorsal furrow with three pairs of small glandularia platelets, all restricted to the posterior half, and not fused to dorsal shield, 2) two pairs of glandularia typically fused to anterior margin of ventral shield, 3) genital field with 4 pairs of acetabula, and 4) the glandularia located near the anterior margins of the acetabula-bearing genital plates free, not fused with the ventral shield. The latter character state is also found in females of Villaxonopsalbia sudafricana Cook, 1999 , representative of a monotypic genus known from South Africa. Villaxonopsalbia females are unique among Axonopsalbia -like mites in the fusion of the excretory pore with the combined acetabular plates and postgenital sclerite ( Cook 1999).

Etymology. The new genus name is a combination of lagoena (Latin, = bottle, flask) and Axonopsalbia .

Figures

FIGURE 6. Lagoenaxonopsalbia comorosensis sp. nov., male holotype, Hajangoua stream, Mayotte: A = dorsal; B = ventral; C = cauda, ventral view; D = gnathosoma and palp; E = palp; F = I-L; G = IV-L; H = ejaculatory complex. Scale bars = 100 µm.

FIGURE 7. Lagoenaxonopsalbia comorosensis sp. nov., female (A–C, F from River Antanana, D–E from River Djalimou, Mayotte): A = dorsal shield; B = ventral; C = genital field; D = gnathosoma and palp; D = palp (P-1 lacking); E = palp; F = gential plate region. Scale bars = 100 µm.