Pseudoalliphis, Mašán, Peter & Halliday, Bruce, 2009

Mašán, Peter & Halliday, Bruce, 2009, Three new genera of the mite family Eviphididae (Acari: Mesostigmata), Zootaxa 2013, pp. 43-57 : 44-45

Pseudoalliphis gen. nov.

( Figs 1, 2 , 13, 14, 18, 23 )

Type species Alliphis sculpturatus Karg, 1963 .

Description (female). Dorsal idiosoma. Idiosoma dorso-ventrally flattened. Dorsal shield entire, suboval, completely covering dorsal idiosoma, posterior end overlapping slightly onto ventral idiosoma; anterior extension of the shield overlapping onto ventral surface beyond vertex, fused to anterior parts of peritrematal shields to form an arched structure bearing shortened setae j1 and z1. Dorsum with coarse punctate-reticulate sculpture, bearing 28 pairs of subequal setae. Vertical setae j1 thickened and pointed apically, z1 fine and pointed, j1 and z1 positioned on ventral extension of dorsal shield, conspicuously shorter than setae on dorsum.

Ve nt r al idiosoma. Sternal shield well sclerotised, bearing three pairs of setae and two pairs of pores; first pair of sternal pores small, slit-like, oriented at approximately 45° to longitudinal axis. Sternal shield and endopodal platelets II almost separated. Endopodal platelets III anteriorly connected with endopodals II. Metasternal platelets absent, metasternal setae st4 inserted on soft cuticle, adjacent metasternal pores inserted on microplatelets. Genital shield slightly constricted medially, with a pair of posterior genital setae; genital pores inserted on soft cuticle. Anal shield subtriangular. Presternal, exopodal and postgenital plates absent. Peritrematal shields well developed, widened. Metapodal platelets present.

Gnathosoma . Palptarsus without paired macroeupathidium, tarsal apotele two-tined. Movable digit of chelicerae bidentate. Tectum with elongated central projection and short, simple lateral prongs.

Legs. Setation of legs I-II-III-IV: coxae 2-2-2-1, trochanters 6-5-5-5, femora 13-11-6-6, genua 11-11-8-7, tibiae 11-10-7-7; tarsi II–IV with 18 setae.

Etymology. The genus name Pseudoalliphis refers to the similarity of the new genus to the related genus Alliphis .

Notes on the genus. The new genus is characterised by an exceptional combination of characters that occur in several eviphidid genera, including Crassicheles , Rafaphis and Halolaspis gen. nov. (endopodal platelets II and sternal shield separated), Alloseius gen. nov. (ventral position of dorsal shield setae j1 and z1; fusion of anterior sections of peritrematal shields and dorsal shield to form an arched ventral shield structure; coarse punctate-reticulate dorsal ornamentation), Rafaphis (ventral expansion of posterior dorsal shield), Canestriniphis , Cryptoseius , Scarabaspis and Halolaspis (absence of metasternal platelets). We consider the new genus Pseudoalliphis to represent a connecting link between unspecialised edaphic genera such as Rafaphis and Halolaspis through Alloseius towards the genera with phoretic species specialised for life in temporary and spatially limited habitats. The genus Pseudoalliphis is presently monotypic.

The genera Pseudoallphis and Alliphis may be distinguished from one another by a number of characters. In Pseudoalliphis , (1) the anterior sections of the peritrematal shields are extensively fused with each other and with the dorsal shield; (2) the fusion of the peritrematal shields with the expanded anterior margin of the dorsal shield forms an arch-shaped antero-ventral shield structure that embraces coxae I ( Fig. 2 ); (3) the dorsal shield is expanded ventrally around the vertex so that dorsal shield setae j1 and z1 setae are inserted on the ventral surface ( Fig. 2 ); (4) the endopodal plates between coxae II and III are almost free from the sternal shield; (5) the posterior margin of the dorsal shield is slightly expanded so that a narrow strip of the shield is visible ventrally; (6) the exopodal platelets are absent. In Alliphis , (1) the anterior sections of the peritrematal shields are not fused with each other, and are fused with the dorsal shield only in the anterolateral areas; (2) there is no arch-shaped antero-ventral shield structure around coxae I ( Fig. 4 ); (3) setae j1 and z1 are inserted in their normal positions at the anterior end of the dorsal shield ( Fig. 3 ); (4) endopodal platelets II are completely fused to the sternal shield; (5) the posterior margin of the dorsal shield is not expanded ventrally; (6) exopodal platelets are present ( Fig. 4 ). Also, the tectum of P. sculpturatus has smooth simple lateral prongs ( Fig. 18 ), quite different from those of a typical species of Alliphis , such as A. halleri ( Fig. 17 ).

Figures

FIGURES 1 – 2. Pseudoalliphis sculpturatus comb. nov., female. 1. Dorsal idiosoma; 2. Ventral idiosoma. Scale: 100 µm.

FIGURES 11 – 24. Morphological structures in Eviphididae, females. 11. Halolaspis hypedon, sternal shield; 12. H. hypedon, sternal shield, different specimen; 13. Pseudoalliphis sculpturatus, chelicera, lateral view of distal segment; 14. P. sculpturatus, chelicera, ventral view; 15. H. hypedon, chelicera; 16. H. hypedon, peritrematal shield; 17. Alliphis halleri, tectum; 18. P. sculpturatus, tectum; 19. Alloseius pratensis, cheliceral digits, lateral view (after Karg, 1965); 20. H. hypedon, tectum; 21. A. pratensis, hypostome (after Karg, 1965); 22. A. halleri, hypostome; 23. P. sculpturatus, hypostome (after Karg, 1963); 24. H. hypedon, hypostome. Scale bars: 50 µm (Figs 11, 12, 15, 16 and 24) and 25 µm (Figs 13, 14, 17, 18 and 20). Figs 19 and 21 – 23 not to scale.

FIGURES 3 – 4. Alliphis halleri, female. 3. Dorsal idiosoma; 4. Ventral idiosoma. Scale: 100 µm.