Cretachyzeria, Liu & Fan & Ren, 2025

Liu, Yu, Fan, Qing-Hai & Ren, Dong, 2025, A Cretaceous mite with ultra-long setae possibly reveals the early survival strategy of Chyzeriidae, Fossil Record 28 (2), pp. 241-248 : 241-248

Genus Cretachyzeria gen. nov.

Type species.

Cretachyzeria macroseta sp. nov.

Diagnosis.

Active postlarval form: Prodorsum bears dense and relatively short setae, narrowing anteriorly; crista metopica located in the middle region near leg I, sensillary area oval. Two pairs of eyes on the edge of prodorsum and positioned near the base of leg II. Hysterosoma with 2 pairs of large cylindrical protrusions at the level of leg III, bearing extremely long and dense setae that cover the entire posterior dorsum and extend far beyond the posterior edge of dorsum. Ventral surface with dense and relatively short setae; genital opening slit-like, located posterior to leg IV coxae, surrounded by a pair of sclerites (genital cover flaps). Palps slender and elongated, bearing dense setae; tibial claw well developed, smooth, the end curved into a knife shape; tarsus elongated, slender at base, then gradually widens, and the end circular. Legs long and slender, each tarsus with a pair of smooth claws.

Etymology.

The generic epithet Cretachyzeria is a combination of the prefix Cret-, referring to the Cretaceous period, and the modern genus name Chyzeria (the type genus of the family Chyzeriidae ).

Remarks.

The new genus Cretachyzeria gen. nov. is provisionally placed in Chyzeriidae based on its similarity to Parachyzeria Hirst (subfamily Pteridopinae ), particularly the presence of two pairs of prominent setiferous protrusions on the idionotum. It differs from Parachyzeria in several key features: it lacks the antero-medial protrusion characteristic of Parachyzeria ; the anterior margin of the prodorsum is nearly truncate rather than tapered; and the setae on the protrusions are significantly longer, extending well beyond the posterior margin of the idiosoma, whereas those of Parachyzeria do not.