Hippopodina inarmata, Almeida & Larré & Vieira, 2021

Almeida, Ana C. S., Larré, Igor R. N. M. & Vieira, Leandro M., 2021, Ten new species of marine bryozoans (Gymnolaemata: Cheilostomatida) from Brazil, Zootaxa 5048 (4), pp. 511-537 : 531-533

Hippopodina inarmata n. sp.

( Fig. 11A–D )

urn:lsid:zoobank.org:act:278380A7-9184-4345-82C7-07F339D8D21B

Material examined. Holotype: UFBA 2003.1 , 13°45’ S, 38°50’ W, Baía de Camamu, Costa do Dendê , Bahia, Brazil, coll. by LAMEB-UFBA, 2004 . Paratypes: UFBA 2009.1 , 12º48’ S, 38º10’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 28 m, coll. by LAMEB-UFBA, 2000 ; UFBA 3553.4 , 12º47’ S, 38º06’ W, Camaçari, Costa dos Coqueiros, Bahia, Brazil, 26 m, coll. by LAMEB-UFBA, 2008 ; UFPE 916 , 4 º49’– 5º10’ S, 36º10’– 36º50’ W, Bacia Potiguar, Rio Grande do Norte, Brazil, coll. by Petrobras, 2009–2010 . Additional specimens: UFBA 262.1 , 13°45’ S, 38°50’ W, Baía de Camamu, Costa do Dendê , Bahia, Brazil, coll. by LAMEB-UFBA, 2004 ; UFBA 1339.3 , 13°53’ S, 39°59’ W, Camamu , Costa do Dendê, Bahia, Brazil, 18 m, coll. by LAMEB-UFBA, 2004 .

Diagnosis. Hippopodina with convex, evenly pseudoporous frontal shield, without a suboral umbo, primary orifice hoof-shaped with mediolateral condyles, low peristome with tubercles, no avicularia and ovicelled zooids with dimorphic orifice (broader than non-ovicelled zooids).

Type locality. Baía de Camamu, Bahia, Brazil .

Etymology. The specific epithet refers to the absence of avicularia, in contrast to the other species of this genus.

Description. Colony encrusting, uni- to multilaminar ( Fig. 10A ).

Autozooids subrectangular to subhexagonal (0.899–1.004– 1.196 mm long, n = 30, SD = 0.070 mm; 0.554– 0.666– 0.960 mm wide, n = 30, SD = 0.086 mm), separated by distinct grooves with raised walls. Frontal shield convex, nodular, and uniformly perforated by small pseudopores placed between the frontal nodules; secondary calcification can obscure frontal pseudopores; marginal pores tiny and scarcely distinguishable from the pseudopores. Primary orifice hoof-shaped, rounded distally and with concave proximal rim (0.211–0.223– 0.239 mm long, n = 30, SD = 0.008 mm; 0.206–0.225– 0.247 mm wide, n = 30, SD = 0.011 mm); condyles present, paired, mediolateral, subtriangular, and hooked downwards. Peristome as a tuberculate low rim around primary orifice ( Fig. 10B ).

Avicularia not observed (supposedly absent).

Ovicell hyperstomial to submerged in distal autozooids, globular (0.421–0.427– 0.432 mm long, n = 2, SD = 0.009 mm; 0.685–0.700– 0.715 mm wide, n = 2, SD = 0.021 mm); ooecium with same calcification as frontal wall; ovicelled zooids with a subcircular primary orifice with proximal margin slightly concave ( Fig. 10C, D ).

Remarks. Among the 12 living species of Hippopodina , H. inarmata n. sp. is more similar to Hippopodina ambita ( Hayward, 1974) from the Mediterranean Sea, as both have mediolateral condyles, contrasting with the other species that have proximolateral condyles. Hippopodina inarmata n. sp. differs from H. ambita , however, in having a low peristome with tuberculate calcification (forming lateral flaps in H. ambita ) and in the absence of avicularia (latero-oral in H. ambita ) ( Hayward 1974).

Two other congeners were already recorded from Brazil — Hippopodina feegeensis ( Busk, 1884) and Hippopodina pulcherrima ( Canu & Bassler, 1928b) ( Vieira et al. 2008, 2021). Differences among H. inarmata n. sp., H. feegeensis and H. pulcherrima are related to the proximal margin of the primary orifice (concave proximally in H. inarmata n. sp.; almost straight in H. feegeensis and H. pulcherrima ), and avicularia (not observed in H. inarmata n. sp.; typically paired in H. feegeensis and H. pulcherrima ) ( Canu & Bassler 1928b; Tilbrook 1999).

As H. inarmata n. sp., three other species— H. californica Osburn, 1952 , H. irregularis Osburn, 1940 and H. pectoralis Harmer, 1957 —also lack avicularia ( Harmer 1957; Osburn 1940, 1952). Hippopodina californica has proximolateral condyles, a peristome orifice with lateral flaps and a suboral umbo; H. irregularis also has proximal lateral condyles and the peristome is a low margin with smooth calcification; H. pectoralis has a transversely elliptical orifice, proximolateral condyles and a suboral umbo ( Harmer 1957; Osburn 1940, 1952). Thus, the combination of a fully pseudoporous frontal shield without a suboral umbo, a hoof-shaped primary orifice with mediolateral condyles, a peristome with tubercles and no avicularia distinguishes H. inarmata n. sp. from all congeners.

Distribution. Atlantic: Brazil (Bahia state). Hippopodina inarmata n. sp. encrusts corals and calcareous nodules; 18– 28 m.

Figures

FIGURE 10. A–C. Crepidacantha browni n. sp., UFBA 728.1, holotype. A. Autozooids. B. Detail of primary orifice. C. Ovicelled zooid. Scale bars: A. 200 µm; B, C. 100 µm.

FIGURE 11. A–D Hippopodina inarmata n. sp., UFBA 2003.1, holotype. A. Overview of an encrusting colony fragment. B. Detail of primary orifice. C. Autozooids and ovicelled zooid. D. Detail of ovicells. Scale bars: A, B, C. 500 µm; D. 200 µm.