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Table 1 Maturity scale for oviparous elasmobranch females adapted from Serra-Pereira et al. (2010)

From: The development of the oviducal gland in the Rajid thornback ray, Raja clavata

Stages Macroscopic Histological
Immature Ovaries small, whitish and homogeneous; undistinguishable ovarian follicles. Absent oviducal gland and thread-like narrow uterus Ovary with primordial (smaller than 0.3 mm) and primary follicles (0.3 to 1 mm) connected to the germinal epithelium and tunica albuginea. Uterus composed mainly by connective tissue, covered by simple columnar epithelium with some invaginations; some blood vessels present
Developing Ovaries enlarged with small follicles in different stages of development, sometimes restricted to the anterior part of the ovary. Developing oviducal gland. Enlarged uterus. Three subphases can be considered: Early developing: ovary with only white follicles with less than 2 mm, oviducal absent or beginning to form (whitish); Mid-developing, ovary with yellow follicles below 8 mm (commonly below 30 follicles), developing oviducal gland; Late developing: ovary with a great quantity of yellow follicles (commonly above 30) with diameter less than 15 mm, oviducal gland completely formed Ovary with primordial, primary, pre-vitellogenic and vitellogenic follicles (smaller than 15 mm). Oviducal gland can show only the beginning of gland tubules formation or be completely formed, with differentiation of the four secreting zones, depending on the advance in maturation. Beginning of secretions production in the oviducal gland and uterus. Uterus more invaginated and vascularized
Spawning capable Large ovaries with large yolked follicles that can reach around 40 mm in diameter. Oviducal gland and uterus fully developed Follicles in all stages can be observed in the ovary. Secretions present in the gland tubules of the oviducal gland. Uterus highly invaginated, showing longitudinal folds producing secretions to the lumen
Actively spawning Ovaries and oviducal gland similar to the spawning capable phase. Large yolked egg may be present in the oviducal gland. Egg capsule present in the uterus and attached or not to the oviducal gland. Capsules may be starting to be produced or be fully formed, hardened and dark; present in one or both uterus Follicles in all stages can be observed in the ovary. Post-ovulatory follicles can be present in the ovary. Oviducal gland tubules full of secretion materials. Secretions also present in the gland lumen. Uterus producing secretions to the lumen
  1. Both macroscopic and histological descriptions are presented