First Solenogastres (Mollusca, Aplacophora) from Puerto Rico: descriptions of two new species and notes on their coral hosts Author Cobo, M. Carmen 0000-0002-8481-2086 Smithsonian Institution, National Museum of Natural History, Washington, DC, USA Author Breusing, Corinna 0000-0001-6845-0188 Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA Author Quattrini, Andrea M. 0000-0002-4247-3055 Smithsonian Institution, National Museum of Natural History, Washington, DC, USA Author Herrera, Santiago 0000-0001-7204-9434 Smithsonian Institution, National Museum of Natural History, Washington, DC, USA & Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA Author Strong, Ellen E. 0000-0001-7181-4114 Smithsonian Institution, National Museum of Natural History, Washington, DC, USA text ZooKeys 2025 2025-11-26 1261 115 140 journal article 313247 10.3897/zookeys.1261.164889 20f3c40d-b9c7-41d2-968e-9006cdc3a955 B0DE435D-8997-4F12-B664-05273C97A593

Table 2. Main distinguishing characters of Strophomenia species. Coral host identifications follow the names provided in the literature. The number of examined specimens (n) is indicated below each species name, based on the respective original description; + indicates present; - not available / known.

	S. lacazei (n = 3)	S. debilis (n = 1)	S. indica (n = 28)	S. ophidiana (n = 1)	S. regularis (n = 1)	S. scandens (n = 3)	S. boricua (n = 1)
Distribution	La Calle (Algeria)	Buton Strait (Indonesia)	Kei Islands, Java, Bay of Bima, W Salawati, Timor (Indonesia)	Honshu Islands (Japan)	Honshu Islands (Japan)	Bird Islands (Hawaii)	Puerto Rico
Depth (m)	Littoral	75–94	18–506	95–140	130–180	625–1035	389
Size (mm)	45 × 2–3	6 × 0.75	11–39 × 1–2.5	43 × 2.5	9 × 1	32–39 × 1.6–2.1	18 × 1–1.8
Habitus	Pale brown	Brown	Brown to yellow	Creamy white	?	?	Brown to orange
Pedal fold	1 triangular	3 triangular equal size	1 medial and two small lateral	?	1 small	1 medial and 2 small lateral	1 almost rectangular
Ventrolateral foregut glands	Fusion with foregut not observed. Only right side. Folded.	Fusion with foregut ventral as separated tubes. Folded.	Paired in all their extension.	Fusion with foregut ventral.	?	Fusion with foregut ventral single (ventral?). Then continue as 2 tubes.	Fusion with foregut dorsal and single. Two tubes, first only on the right side. Slightly folded.
Genital opening	Paired	Paired	Paired	Paired	Paired	Single (short)	Single
Radular sac	-	Rudimentary	-	-	?	-	Rudimentary
Dorsoterminal sensory organ	Not observed	-	+	+	+	+	+
Seminal receptacle	8	?	≥ 13	23	12	15–18	5
Coral host	’ Muricea’	’ Gorgonids’	’ Gorgonids’	‘ Acanthogorgia angustiflora ’	‘ Dendronephyta’	‘ Acanthogorgia armata ’	Villogorgia nigrescens
Reference	Pruvot 1899: figs 23–31	Nierstrasz 1902: pl. IV figs 114–117	Nierstrasz 1902: pl. II figs 101–112	Heath 1911: pls 1, 8, 9, 18	Heath 1911: pls 24, 26	Heath 1911: pls 6, 12, 13, 32, 37	This work