Ircinia cf. reteplana (Topsent, 1923)

Kelly, Joseph B. & Thacker, Robert W., 2021, New shallow water species of Caribbean Ircinia Nardo, 1833 (Porifera: Irciniidae), Zootaxa 5072 (4), pp. 301-323 : 316-317

Ircinia cf. reteplana (Topsent, 1923)

Figures 14 , 15 ; Tables 1 , 2 .

Representative specimens: USNM 1641981 (JK18x6; 24.6609, -81.4563; appx. 1.2 m depth; coll. J.B.K.; 5 July 2018) , USNM 1641982 (JK18x7; 24.6609, -81.4563; appx. 1.2 m depth; coll. J.B.K.; 5 July 2018) , USNM 1641984 (JK18x9; 24.6609, -81.4563; appx. 1.2 m depth; coll. J.B.K.; 5 July 2018) , USNM 1641985 (JK18x10; 24.6609, -81.4563; appx. 1.2 m depth; coll. J.B.K.; 5 July 2018), USNM 1641989 (JK18x14; 24.6609, -81.4563; appx. 1.2 m depth; coll. J.B.K.; 5 July 2018) .

Collection locality: Summerland Key, Florida.

External morphology. Ircinia with a flattened, branching morphology. Branches are usually not interconnecting ( Figure 14 ). Surface with 1–1.2 mm-high conules. Most oscula are around 0.5 cm in diameter and are found across the face of the branches, where they sit flush, as well as at the edges of the branches.

Interior morphology. Massive fascicular fibers are tightly bound, 90–250 µm wide, and heavily cored. Interconnecting fibers 20–80 um wide, moderately cored with spicules and sand ( Figure 15 ). Irciniid filaments 2–6 µm wide, terminating in spherical knobs measuring 9–15 µm in diameter. Cortex routinely incorporates sand and foreign spicule fragments.

Ecology. Specimens were collected from a Thalassia -dominated seagrass bed and co-occurred next to I. campana , sometimes within a meter of each other. Symbiotic metazoans in the sponge are mostly crustaceans and polychaetes.

Remarks. The body shape of I. reteplana Topsent, 1923 is distinct from those of the aforementioned Ircinia in that it is composed of flattened, interconnecting branches. Because the Floridian Ircinia growth form, called ‘Ramose’ in Kelly et al. (2021), often displays a flattened branching morphology, we designate this growth form as Ircinia cf. reteplana Topsent, 1923 , and maintain it as conferre due to the moderate degree of coring observed in secondary fibers, a characteristic that is absent from I. reteplana Topsent, 1923 . Additionally, the branches of I. cf. reteplana seldom interconnect, as is reported for I. reteplana Topsent, 1923 , and can also possess a rounded branching morphology. This growth form represents either a new species of Ircinia or it represents an extension of the documented range of I. reteplana to the Florida Keys. For reference, the range of I. reteplana encompasses the entirety of the Antilles and spans the Caribbean to the coast of Venezuela, and extends to the tip of the Yucutan Peninsula ( van Soest et al. 2021). The collections of I. strobilina , I. felix , and I. campana were made within the documented ranges of these species ( Table 1 ).

Figures

FIGURE 14. Ircinia cf. reteplana (Topsent, 1923). A: USNM 1641984, B: USNM 1641982, C: USNM 1641981, D: USNM 1641985, E: USNM 1641989.

FIGURE 15. Histological sections of Ircinia cf. reteplana USNM 1641982. A: Image showing moderately cored secondary fibers. A primary fiber terminates in a conule on the left of the image. B: Two primary fibers running in parallel, connected by a mesh of secondary fibers. A group of spicules is circled below the topmost primary fiber. Note the difference in the degree of coring of secondary fibers between A and B. Annotations follow Figure 3.