Haliclona (Reniera) kahoe, Vicente & Rutkowski & Lavrov & Martineau & Timmers & Toonen, 2025

Vicente, Jan, Rutkowski, Emily, Lavrov, Dennis V., Martineau, Gabrielle, Timmers, Molly & Toonen, Robert J., 2025, Integrative taxonomy of introduced Haplosclerida and four new species from Hawaiʻi, Zootaxa 5566 (2), pp. 243-272 : 251-254

Haliclona (Reniera) kahoe sp. nov.

LSIDurn:lsid:zoobank.org:act: 10EF032A-6090-464A-BC51-12059BCD97A5

( Fig. 4–5 , Table 2 )

Haliclona sp. JV 1; Vicente et al., 2022b, Vicente et a l., 2022a: Sup. Fig. S7

Holotype and type locality. BPBM C1539 -ARMS on reef at Moku o Loʻe ( Coconut Island ), Pūpūkea, Kāne‘ohe Bay, Oʻahu (21.4335 °N, - 157.7863 °W); 0.3 m, coll. Jan Vicente, 2018-03-16 . Paratypes. BPBM C1570 , BPBM C1540 , BPBM C1538 - ARMS on reef at Moku o Loʻe (Coconut Island), Kāne‘ohe Bay , Oʻahu (21.4335 °N, - 157.7863 °W); 3 m, coll. Jan Vicente, 2017-11-21, 2018-03-16, 2018-06-11, respectively . BPBM C1553 , BPBM C1554 , BPBM C1552 , BPBM C1551 , and BPBM C1537 -ARMS in mesocosms at the Hawai‘i Institute of Marine Biology ( HIMB), Moku o Loʻe ( Coconut Island ), Kāne‘ohe Bay , Oʻahu (21.4334 °N, - 157.7868 °W); 0.3 m, coll. Jan Vicente, 2016-12-19, 2017-02-13, 2017-08-01, 2018-01-19, 2018-03-16, and 2018-06-11 respectively. Additional vouchers with metadata can be found in Table S1 .

Diagnosis. A soft, thin to thickly encrusting Haliclona (Reniera) displaying a variety of irregular, and regular cushion shaped growth morphologies with apical oscula that are mainly light brown in color. The skeleton is exclusively composed of oxeas (154–197 x 1– 9 µm) arranged mainly in unispicular, isotropic, isodictyal, reticulation throughout the choanosome and ectosome.

Description ( Fig. 4 ): Thin to thickly encrusting with erect regular to irregular oscular lobes. Individuals spread laterally measuring 1–4 cm in length, width of ≤ 1 cm and a thickness up to 0.5 cm. Oscula measure 1–3 mm in diameter and may rise 0.5 cm in height. Some colonies have multiple oscular lobes stemming from one base. The base is thinly encrusting, spreading laterally. Base’s surface is smooth, even, and occasionally irregular with few microscopic pores. In some specimens multiple, long, thin anastomosing branches project outward from the base. Oscula may spread laterally across branches. Superficial canals are slightly pronounced along the base of some individuals but are rarely present. Consistency is soft, delicate, compressible, and easily torn. Color in live specimens ranges from light brown, light purple to greyish yellow. A gradient from dull yellow to purple can be observed concurrently on the same individual.

Skeleton ( Fig. 5a–h ): Ectosome is ill defined in some specimens but when present, is composed of an isotropic unispicular, isodictyal reticulation of oxeas. Rectangular (80–120 µm in diameter) or quadrangular meshes (up to 150 µm in diameter) are composed of 5–10 oxeas which meet at the nodes with very little spongin. The lack of spongin gives the ectosome a translucent appearance. Choanosome in some specimens is less organized and consists of an isotropic to subisotropic reticulation forming meshes similar in size and shape to those found in the ectosome. Few discernable unispicular ascending primary tracts (spaced 100–150 µm apart) are visible in some individuals but are not connected by a regular frequency of secondary tracts ( Fig. 5b ). Spongin and small auxiliary oxeas is scattered sporadically throughout the choanosome.

Spicules ( Fig. 5 i-j); Table 2 ): Oxeas are straight or slightly curved with acerate tips measuring 154–162–197 x 1–4.5– 9 μm ( Fig. 5 i-j) Oxeas with both round and acerate ends are rare.

Taxonomic remarks. The delicate unispicular, isotropic to subisotropic reticulation of oxeas in both the choanosome and ectosome of Haliclona (Reniera) kahoe agrees with both H. ( Reniera ) ( Schmidt, 1862) and H. ( Halichoclona ) de Weerdt, 2002. Yet, the soft consistency, compressibility, and the lack of subectosomal or choanosomal spaces is more similar to those of H. ( Reniera ) than of H. ( Halichoclona ). The skeleton lacks a ladder-like morphology with primary lines connected irregularly (characteristic of H. (Rhizoniera) Griessinger 1971 or regularly (characteristic of H. ( Haliclona ) de Weerdt, 2002) by unispicular secondary lines. Skeleton reticulation is also not subhalichondroid with multispicular lines as defined for H. ( Gellius ) Gray 1867 nor does it tend to form rounded meshes in the ectosome by paucispicular lines as defined for H. (Soestella) de Weerdt, 2002. Although, H. ( Reniera ) is the most appropriate classification for this species, the ectosomal skeleton when present is not “very regular” nor does the presence of spongin conform to its definition. Spongin is not only present at the nodes of spicules that build the skeletal framework but is also abundant throughout the choanosome.

There are 23 Haliclona (unknown subgenera) spp., two Haliclona (Haliclona) spp., three Haliclona (Reniera) spp. and one Haliclona (Rhizoniera) spp. sharing a thin to thick, irregularly encrusting morphology, similar color patterns and spicule composition to H. (Reniera) kahoe ( Table S2 ). However, these species can be discarded as possible matches by 1. the presence of smaller oxeas (as in H. carteri Burton 1954 (40 x 8 μm), H. hydroida Tanita & Hoshino 1989 (120 –145 x 7–14 µm), H. innominata ( Kirkpatrick 1900) (108 x 2.5 µm), H. isodictyalis Bergquist 1961 (130 x 7 μm), H. macropora ( Thiele 1905) (118–125 × 4–5.2–8 μm), H. minima ( Lendenfeld 1887) (67 x 3 µm), H. nitens Desqueyroux-Faúndez 1990 (100–118 × 1.6–4 μm), H. offerospicula Hoshino 1981 (75–82–90 x 2–2.8–3 μm), H. rectangularis ( Ridley & Dendy 1886) (88 x 9 μm), H. reversa ( Kirk 1911) (100 x 5 μm), H. tenuis Hoshino, 1981 (83–100 x 5–8 μm), H. translucida Desqueyroux-Faúndez, 1990 (94–116 x 6–7 μm), H. venustina ( Bergquist, 1961) (100 x 4 μm), H. (Haliclona) tonggumiensis Kang et al., 2013 (60–110 x 1– 5 μm), H. (Reniera) cinerea ( Grant 1826) (76–113 x 5–10 μm), H. (Reniera) clathrata ( Dendy 1895) (107 x 6 μm), H. (Rhizoniera) e namela de Laubenfels 1930) 2. larger oxeas (as in H. densaspicula Hoshino, 1981 (187–250 x 3–15 μm), H. maxima Bergquist & Warne, 1980 (274–417 μm), H. (Haliclona) ieoensis Kim et al. 2017 (160–230 × 2.5–12.5 μm), 3. Firm or hard consistency (as in H. glabra Bergquist, 1961 , H. rapanui ( Desqueyroux-Faúndez, 1990) , H. sataensis Hoshino, 1981 ) and 4. Presence of multispicular tracts throughout the skeleton (as in H. madagascarensis Vacelet et al. 1976 , and H. tenacior Bergquist, 1961 ) Other clearly distinguishable characters setting H. (Reniera) kahoe apart from the remaining species are the absence of a conulose surface (characteristic of Haliclona lentus Hoshino, 1981 ), rough oxeas with an uneven surface (diagnostic of Haliclona scabritia Tanita & Hoshino, 1989 and the absence of a “very regular” continuous ectosome (as observed in Haliclona (Reniera) venusta ( Bowerbank 1875) . Of the H. ( Halichoclona ) spp., H. (Halichoclona) mokuoloea ( de Laubenfels, 1950) from Kāneʻohe Bay shares similar consistency and an isodictyal reticulation of oxeas within the skeletal framework. Nevertheless, H. (Halichoclona) mokuoloea is set apart by the yellow, reddish color, smaller oxeas (120–135 x 6 μm) and massive growth morphology.

Habitat and ecology. All specimens were common in confined cryptic environments of Autonomous Reef Monitoring Structures (ARMS). Specimens were collected from ARMS deployed on the patch reef slope adjacent to Moku o Loʻe (Coconut Island), and ARMS inside mesocosms supplied with unfiltered flow through seawater at the Hawai‘i Institute of Marine Biology (HIMB) in Moku o Loʻe (Coconut Island). Time series observations show quick growth and abundance of Haliclona (Reniera) kahoe throughout pioneering and climax stages of succession (Sup. Fig. S3 , Sup. Fig. S 7 in Vicente et al., 2022a).

Distribution. Moku o Loʻe (Coconut Island), Kāneʻohe Bay on the island of Oʻahu, Hawaiʻi.

Etymology. The given name is based on Lo‘e’s faithful brother Kahoe, who was a farmer that regularly provided crops he had grown to his brother Pahu. We use the feminine kahoe following the feminine gender of Haliclona and Article 31.2 of the International Code for Zoological Nomenclature (http://www.iczn.org/, accessed on October 16, 2023).

Figures

FIGURE 3. Skeletal architecture of Haliclona (Gellius) loe sp. nov. Perpendicular section through the ectosome and choanosome in a, holotype BPBM C1523; b, paratype BPBM C1549; c, paratype BPBM C1673; close up of the choanosome in d–e paratype BPBP C1534. Light microscopy images in f, oxeas of paratype BPBM 1533 SEM images in g, oxeas and h, sigmas of holotype BPBM C1523. Scale bars: a–b, 500 µm; c, 250 µm; d–e, 100 µm; f–g, 50 μm; h, 5 μm.

FIGURE 4. In situ growth variations of Haliclona (Reniera) kahoe sp. nov. a, holotype BPBM C1539; b, paratype BPBM C1538; c, paratype BPBM C1551; d, paratype BPBM C1537; e, paratype BPBM C1540; f, paratype BPBM C1570; g, paratype BPBM C1554; h, BPBM C1553; i, paratype BPBM C1552. Scale bars: a-f, 1 cm; g, 0.5 cm; h-i, 1 cm.

FIGURE 5. Skeletal architecture of Haliclona (Reniera) kahoe sp. nov. Perpendicular section through the ectosome and choanosome in a-b, holotype BPBM C1539; c-d, paratype BPBM C1537; e-f, paratype BPBM C1551. Tangential section of the ectosome in g-h, paratype BPBM C1537. Light microscopy images of i, first oxea from holotype, second oxea from BPBM C1538 and third from BPBM C1540. SEM images of oxeas from holotype j. Scale bars: a, c, e, f, 500 µm; b, d, g, 300 µm; h, 100 µm; i–j 50 μm.

FIGURE 7. In situ growth variations of Haliclona (Soestella) caerulea. a, specimen BPBM C1519; b, specimen BPBM-C1545 associated with Jania adhaerens and with embryos zoomed in subpanel within b; c–g, specimens BPBM C1638, BPBM C1520, BPBM C1544, BPBM C1543, and BPBM C1541 respectively. Scale bar: a–g, 1 cm; subpanel in b, 1 mm.