Integrative taxonomy of introduced Haplosclerida and four new species from Hawaiʻi Author Vicente, Jan Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Ma ̄ noa, Ka ̄ ne‘ohe, HI, 96744, USA. Author Rutkowski, Emily Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Ma ̄ noa, Ka ̄ ne‘ohe, HI, 96744, USA. Author Lavrov, Dennis V. Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 343 A Bessey, IA, 50011 - 1020, USA. Author Martineau, Gabrielle Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Ma ̄ noa, Ka ̄ ne‘ohe, HI, 96744, USA. Author Timmers, Molly Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Ma ̄ noa, Ka ̄ ne‘ohe, HI, 96744, USA. & Pristine Seas, National Geographic Society, Washington, DC 20036, USA. Author Toonen, Robert J. Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Ma ̄ noa, Ka ̄ ne‘ohe, HI, 96744, USA. text Zootaxa 2025 2025-01-08 5566 2 243 272 https://doi.org/10.11646/zootaxa.5566.2.2 journal article 10.11646/zootaxa.5566.2.2 1175-5326 14702682 85B55E49-BBC7-4321-8CC4-CBD49D29ED43 Haliclona ( Soestella ) caerulea ( Hechtel 1965 ) ( Table 4 ; Fig. 7–8 ) Synonyms and References Sigmadocia caerulea — Hechtel, 1965: 30 , Fig 5 , plate III; Zea, 1987: 69 , Fig 16. Sigmadocia coerulea (misspelling)- Van Soest, 1980: 21 , Fig 7 , Plate II Fig 4 Haliclona caerulea — Cruz-Barraza & Carballo, 2008: 750 , Figs 6 , 7D ; Hajdu, E., Peixinho, S. & Fernandez, 2011: 180; ( Bispo et al. 2016 ): 5, Table 2 Pérez et al ., 2017 : Fig 6 Haliclona ( Soestella ) caerulea , de Weerdt, 2000: 29 , Figs 3F , 16A-E; Bispo, 2019: 104 , Fig 35–37; Pons et al. , 2017: 42 , Fig 20; Vicente et al. , 2020: 111 , Fig 1 ; Vicente et al. , 2022b Table S4–S 5 ; Ugalde et al. , 2021: 37 , Fig 29 Haplosclerida sp. 11 -Vicente et al; 2022b: Table S4–S 5 ; Vicente et al ., 2022a : Suppl. Table S1–2 Haplosclerida sp. 12 -Vicente et al; 2022b: Fig 4 , Table S4–S 5 ; Vicente et al ., 2022a : Suppl. Table S1–2 Additional synonyms are listed in de Weerdt, 2000 Type locality. Rasta’s wreck, Jamaica ( 17°56′30″N , 76°50′0″W ). Material examined. BPBM C1519 -Mammal pens, Moku o Loʻe (Coconut Island), Kāneʻohe Bay, Oʻahu, ( 21.43243 °N , - 157.79078 °W ); 0.5 m , coll. Jan Vicente, 2017-05-29. BPBM C1541, BPBM C1543, BPBM C1544, BPBM C1542 ARMS on reef at Moku o Loʻe (Coconut Island), Kāne‘ohe Bay, Oʻahu ( 21.4335 °N , - 157.7863 °W ); 3 m , coll. Jan Vicente on 2018-03-16 , 2018-06-11 , 2018-06-11 , 2018-06-11 , 2018-06-11 respectively. BPBM C1638 — ARMS in mesocosms at the Hawai‘i Institute of Marine Biology ( HIMB ), Moku o Loʻe (Coconut Island), Kāneʻohe Bay, Oʻahu ( 21.4334 °N , - 157.7868 °W ); 0.3 m , coll. Jan Vicente, 2020 -08-13. BPBM C1520—Keʻehi harbor, Oʻahu ( 21.3208 °N , - 157.894 °W ); 2 m , coll. Jan Vicente, 2018-5-15. BPBM C1545—Sunken City, Kāne‘ohe Bay, Oʻahu, ( 21.4357 °N , - 157.7923 °W ); 2 m , coll. Jan Vicente, 2017-5-25. Jan Vicente, 2018-03-16. Description ( Fig. 7 ). Thickly encrusting, cushion shaped mounds. Consistency may vary from fragile, compressible, firm to hard and difficult to cut when associated with the coralline macroalgae Jania adhaerens . Surface is punctate and can vary from smooth to very rough in specimens associated with J. adhaerens . Oscula were not visible in recruits growing on ARMS but were visible as fused tubular projections in larger individuals measuring 2 to 8 mm in diameter and up to 1 cm in height. Color varies from different shades of light blue, turquoise, light purple (in specimens associated with J. adhaerens ), white or cream. White speckled blotchy pattern is visible on surface of some individuals. Embryos measuring 350–400 µm with developing oxeas were spotted deep in the choanosome of BPBM-C1545 ( Fig. 7b ). Skeleton ( Fig. 8a–h ). Ectosome in recruits growing on ARMS and associated specimen with J. adhaerens show unispicular, isodictyal, reticulation.In larger individuals the ectosome consists of dense, multispicular circular meshes (400–600 µm). The choanosome is disorganized in small recruits but can also form unispicular to paucispicular reticulation of circular meshes (100–150 µm) in larger individuals. Subectosomal and choanosomal spaces (200– 750 µm) are present in larger individuals. Sponging was scarcely present throughout the choanosome. Spicules ( Fig. 8i–j ; Table 4 ). Oxeas are straight and slightly bent mostly with hastate tips 93.5–175.5–210 x 1.2–6.5–11.5 µm ( Fig. 8i ). Sigmas are C-shaped, very abundant throughout the sponge tissue in a single size category 16.9–19.3–23.1 x 0.7–1.3–2 µm ( Fig. 8j ). 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. FIGURE 8. Skeletal architecture of Haliclona ( Soestella ) caerulea . a-b, specimen BPBM C1519; c-d, specimen BPBM-C1545 associated with Jania adhaerens and with embryos (indicated by white arrows); e-f, specimen BPBM C1543; g-h, specimen BPBM C1544. a, c, e, g, show tangential sections of the ectosome. b, d, f, h, show perpendicular sections through the ectosome and choanosome. SEM images of i, oxeas and j, sigmas of specimen BPBM C1519. Scale bars: a–b, 1 mm, c, 500 µm, d, 1 mm, e, 200 µm, f, 500 µm, g, 500 µm, h, 1 mm, i, 50 µm, j, 10 µm. TABLE 4. Spicule measurements of oxeas and sigmas for specimens of Haliclona ( Soestella ) caerulea . Measurements are expressed as minimum–mean (±1 standard deviation)–maximum. N=50 for oxeas and N=10 for sigmas. Measurements for the holotype were provided from Hechtel (1965)

Voucher	Oxeas Length (µm)	Width (µm)	Sigmas Length (µm) Width (µm)
BPBM C1519	104.2–(176±19.9) –196	1.9–(7.1±2.3)–9.3	16.9–(20±1.5)–22.1	1.2–(1.5±0.2)–2.0
BPBM C1520	135.6–(168.9±12.2)–189.0	2.7–(5.4±1.1)–7.7	17.2–(19.2±1.5)–22.0	0.7–(1.0±0.3)–1.6
BPBM C1545	131.2–(166.9±15.4)–198.9	2.2–(6.6±2.4)–10.9	15.1–(18.7±1.6)–20.2	1.0–(1.2±0.2)–1.4
BPBM C1543	144.0–(171.9±10.4)–194.2	3.4–(5.1±0.6)–6.0	15.2–(18.0±1.8)–21.3	0.9–(1.1±0.2)–1.5
BPBM C1541	128.0–(167.9±10.5)–185.7	1.8–(5.2±1.0)–6.5	17.0–(20.0±1.3)–22.0	0.9–(1.1±0.1)–1.4
BPBM C1544	93.5–(191.3±17.2)–209.7	1.2–(7.9±1.3)–9.2	16.2–(18.2±1.9)–22.6	0.7–(1.0±0.2)–1.2
BPBM C1542	126.0–(188.6±11.6)–206.0	1.7–(8.2±1.9)–11.5	18.5–(19.7±0.9)–21.0	0.8–(0.9±0.1)–1.1
BPBM C1638	125.2–(172.8±11.6)–194.8	1.8–(6.3±1.1)–8.1	17.2–(20.4±1.6)–23.1	1.0–(1.3±0.3)–1.9
MNRJ 22768*	136–154.9–176	4–6.6–9	14–16.9–20	None provided
YPM 5047 (h)	143–200	None provided	17–23	None provided

* Specimen from Northeastern Brazil corresponding to 28S sequence (acc. No. MZ366950) ( Bispo et al. , 2019 ). Habitat and Ecology. All specimens were collected on artificial structures including ARMS , pilings, and derelict nets. Long term monitoring of the cryptic sponge community using ARMS showed appearance of H . ( Soestella ) caerulea only on reef ARMS after 18 months (Sup. Fig. S 3 in Vicente et al. , 2022a ), suggesting that this species is present during climax stages of ecological succession. A predation study using native Hawaiian Tiger cowries ( Cypraea tigris ) revealed H . ( Soestella ) caerulea to be a preferred prey item which lacks chemical defenses against fish or mollusks ( Vicente et al. , 2020 ). Embryos present in specimen BPBM-C1545 associated with J. adhaerens supports viviparous reproduction in this species. Distribution. North and Southern Gulf of Mexico ( Mexico ) (Rützler, K.; van Soest, R. W. M.; Piantoni 2009; Ugalde et al. 2021 ), Caribbean ( Cuba , Jamaica ( Hechtel, 1965 ), Puerto Rico ( Van Soest, 1980 ), Martinique ( de Weerdt, 2000 ), Curaçao ( Van Soest, 1980 ), Venezuela (Díaz, H.; Bevilacqua, M.; Bone 1985), Colombia (David-Colón, J.D.; Marin-Casas 2020), Panama , Mexico ), Atlantic (Eastern Brazil ) ( Hajdu et al. , 2011 ), Eastern Indo-Pacific (Hawaiʻi) Pons et al. , 2017 ; Knapp et al. , 2015 ; Eldredge et al. , 2001 , Central Pacific (Palmyra) ( Knapp et al. 2011 ) Taxonomic remarks. Introduced in the last 20 years, this species has now been reported in lagoonal habitats of the main and Northwestern Hawaiian Islands ( Eldredge et al. , 2001 ). Previous descriptions of H . ( Soestella ) caerulea from Moku o Loʻe were made from sponges fouling on artificial floating docks ( Pons et al. , 2017 ) and from sponges growing on dead coral. Here the sponge is observed as a common species of the sponge cryptofauna inside ARMS and a potential invasive within the coral reef cryptobiota of Kāneʻohe Bay. Dimensions of oxeas and sigmas in Hawaiian specimens fit the size categories of the holotype and paratypes from the Caribbean (oxeas: 117–200 x 3–5 µm/sigmas: 13–28 µm) ( Hechtel, 1965 ). These are also similar to specimens previously collected in Hawaiʻi (oxeas:147–220 x 3.7–10 µm/sigmas:15–25 µm) ( Pons et al. , 2017 ). Morphological plasticity between cryptobenthic individuals, and those found on more exposed habitats includes variations in external color (white, blue, light brown and pink) and consistency (hard, soft, brittle) which were similarly observed by Bispo et al. , (2019) and in individuals associated with J. adhaerens by Enríquez et al. , (2009). Differences were also observed in the skeleton structure between small recruits having a confused choanosome and a unispicular ectosome with isodictyal reticulation, and larger individuals having paucispicular circular meshes.