Unionicola (Majumderatax) grandiseta

Smit, Harry, 2017, New records of water mites from standing waters in Thailand, with the description of nine new species (Acari: Hydrachnidia), Zootaxa 4312 (1), pp. 69-91: 76-78

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Unionicola (Majumderatax) grandiseta

n. sp.

Unionicola (Majumderatax) grandiseta  n. sp.

( Fig. 5View FIGURE 5)

Material examined. Holotype female, Kon Chum Dam, Nakhon Ratchasima Province, Thailand, 14-ii-2011 ( RMNH)  ; one female, Huay Nam Kham Noi rivulet, Yasothon Province, Thailand, 15° 48.779ʹ N, 104° 09.415ʹ E, 10-ii-2011 ( RMNH)  .

Diagnosis. Second coxae laterally with two hook-like extensions, third coxae with one hook-like extension. Genital field with two pairs of plates, with two and three pairs of acetabula, respectively. Anterior plates with a stout seta each. P5 with two claws, P4 with a serrated hyaline margin. I-leg-5 distally with a large, pectinate seta. Setae of legs without grooved setae.

Description. Female: Idiosoma 640 (599) long and 559 (486) wide. Dorsum with a pair of elongated platelets, 76 long and 30 wide. Second coxae laterally with two hook-like extensions, third coxae laterally with one hooklike extension. Coxae with a reticulate pattern, fourth coxae with a short posterior apodeme. Genital field: with four plates, anterior plates with two acetabula, posterior plates with three acetabula arranged in a triangle; anterior plates each with a medial stout seta. Length of P1-5: 20, 148, 44, 170, 72. P2 medially with two short setae, P4 with a hyaline serrated ventral margin with a small seta and one more small seta located on ventral margin, P5 with two terminal claws. Length of I-leg-4–6: 112, 86, 94. First leg with many small setae, I-leg-5 distally with one large (>2/3 length I-Leg-5), pectinate seta. Length of IV-leg-4–6: 154, 186, 194 (to tip). IV-leg-4 and -5 with three stiff swimming setae.

Male: Unknown.

Etymology. Named for the large distal seta of I-leg-5.

Remarks. The new species is similar to U. crenipalpis Lundblad, 1969  , but differs (in brackets U. crenipalpis  ) in the presence of five pairs of acetabula (six pairs), the presence of one seta only on the anterior genital plate (two), a much larger serration of P4 (very small serration) and a large and complex distal, pectinate seta of I-leg-5 (a simple seta).


National Museum of Natural History, Naturalis