Cyerce bourbonica Yonow, 2012

Moreno, Karina, Medrano, Sabrina, Gosliner, Terrence M., Wilson, Nerida G., Krug, Patrick J. & Valdés, Ángel, 2025, Phylogenetic systematics of the genus Cyerce Bergh, 1870 (Mollusca: Heterobranchia: Sacoglossa: Caliphyllidae) from the Pacific and Indian oceans with descriptions of nine new species, Zoological Journal of the Linnean Society 204 (1) : -

Cyerce bourbonica Yonow, 2012

( Figs 9B, 10, 11A)

Cyerce sp. 1 Händeler and Wägele 2007: 249; Christa et al. 2014a: suppl. table 1.

Cyerce sp. 2 Wägele et al 2006: 49; Händeler and Wägele 2007: 249; Christa et al. 2014a: suppl. table 1.

Cyerce bourbonica Yonow 2012: 16–19 , pl. 14, pl. 15. Type locality: L’Étang Salé , Réunion, Indian Ocean.

Type material

Cyerce bourbonica — holotype at SMF (337104), L’Étang Salé , Réunion, 14 Dec 2009, 1 m depth, not examined .

Material examined

Hekili Point, Maui, Hawaiian Islands , USA, 1 Apr 2010, 1 m depth, leg. C. Pittman, 1 specimen 3 mm preserved length, dissected (isolate MM77 , CASIZ 182729 ). Village, Ka‘anapali, Maui, Hawaiian Islands , USA, 27 Nov 2008, 3–12 m depth, leg. C. Pittman, 1 specimen (isolate MM75 , CASIZ 180338 ). Ennubuj-Ennylabegan Reef, Ennubuj Isl. , Kwajalein Atoll, Marshall Islands, 12 Apr 2010, leg. S. Johnson, 2 specimens 3–4 mm preserved length, dissected (isolate MM78 A, CASIZ 185099 ). In front of Sheraton Nusa Indah, Bali, Indonesia, 25 Oct 2000, leg. T.M. Gosliner, 2 specimens (isolate MM71 , CASIZ 142130 ). Barracuda Point, Madang Province, Papua New Guinea, Nov–Dec 2012, 6 m depth, leg. T.M. Gosliner, 1 specimen (isolate MM83 , CASIZ 190808 ) .

Range

Widespread in the Indo-Pacific, from the Hawaiian Islands (present study) to the western Indian Ocean ( Yonow 2012).

Description

External morphology: Body colour light cream to pale green ( Fig. 9B). Head light cream to pale green, with white pustules throughout. Tentacles and rhinophores light cream with pale green irregular patching; white pustules with translucent halo at base scattered throughout; few bright yellow spots at tips; small black dots on rhinophores. Cerata lobate, inflated, translucent white to light cream, with pale green irregular patches; white pustules and specks scattered throughout, white specks concentrated below ceratal margin. Ceratal margin outlined with cream band and uniformly distributed bright yellow spots; few black dots sub-marginally on both sides of each ceras. Translucent (probably defensive) gland sacs embedded in tissue beneath cerata margin. Ceratal peduncle greyish, darker than rest of cerata. Foot colour light cream dorsally, with white pustules and bright yellow spots scattered throughout.

Internal morphology: Pharynx about 1 mm, buccal bulb and pharyngeal pouch similar in size. Radula with more than 7 teeth in a 3-mm preserved length specimen ( CASIZ 182729) ( Fig. 10A). Teeth somewhat narrow with blunt tips slightly curved downward ( Fig. 10B). Leading tooth about 100 µm in length, with two rows of ~13 blunt and rhomboidal denticles along either side; denticles distributed evenly across tooth. Size of denticles differ along tooth, smaller near base, larger distally. Penis with embedded penial stylet ( Fig. 11A), penial stylet cylindrical, hollow with oval opening.

Ecology

Associated with the green algae Halimeda spp. Typically found beneath rocks.

Remarks

Cyerce bourbonica Yonow, 2012 was described from several specimens collected from La Réunion and illustrated alive. The original description referenced morphological traits, including semi-translucent beige to green ‘angular’ cerata, minute papillae on surface of cerata, and ceratal margin pigmented with orange and sub-marginal black spots, all observed in our specimens. Yonow (2012) also described basal dark globular patches inside the cerata that were observed in our preserved specimens. The radular teeth described by Yonow (2012) are slightly curved, slender, closely resembling those from our specimens. Although not mentioned in the description, images of the radula in Yonow (2012: fig. 3C, D) show teeth possessing square-shaped denticles similar to those observed in our specimens. Yonow (2012) described the penis as lacking a stylet, whereas our specimens had a deeply embedded stylet, potentially explaining whyYonow (2012) was unable to view a stylet in her specimens.

In phylogenetic analyses, C. bourbonica formed a clade with three new species: C. trowbridgeae sp. nov., C. blackburnae sp. nov., and C. tutela sp. nov. ( Fig. 1A). All these species shared traits, including a small pharyngeal pouch approximately the same size as the buccal bulb, and yellow spots along the ceratal margin. However, C. bourbonica differs from C. blackburnae sp. nov. in having smaller and wider radular teeth with less denticles. The radular teeth of C. bourbonica are much shorter and wider than the teeth of C. tutela sp. nov., and the teeth of C. bourbonica have blunt denticles, whereas sharp triangular denticles are present on the teeth of C. tutela sp. nov. Morphological differences between C. bourbonica and its sister species C. trowbridgeae sp. nov. are described below under the remarks of C. trowbridgeae sp. nov.