Cyerce blackburnae, Moreno & Medrano & Gosliner & Wilson & Krug & Valdés, 2025

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 blackburnae sp.nov.

( Figs 9C, 11C, 13)

LSID: zoobank.org:act: FED3A156-B1AB-406E-A36E-04CCE 0BD361A.

Cyerce sp. 2 Nakano 2018: 118.

Cyerce sp. 3 Christa et al. 2014a: suppl. table 1.

Cyerce sp. 2 Krug et al. 2015: 989, 991.

Type material Holotype: Barracuda Point , Madang, Papua New Guinea, 8 Dec 2012, 6–9 m depth, leg. J. Goodheart, 20 mm preserved length (isolate MM92 , CASIZ 191605 ).

Other material examined

Cement Mixer Reef , WNW of Rasch Pass, in line with Ruo Island, Madang Papua New Guinea, 3–6 m depth, 1 specimen 15 mm preserved length, 11 Jan 1988, leg. T. Gosliner ( CASIZ 070412 ) . Anemone Reef , East of Ruo Island, Madang, Papua New Guinea, 15 Feb 1988, 1 specimen 18 mm preserved, leg. T. Gosliner ( CASIZ 070408 ) . Guam, Aug 2009, 1 specimen 7 mm preserved length, dissected (isolate 09 Gua 01, LACM 186691 ) ; Aug 2009, 1 specimen 7 mm preserved length (isolate 09 Gua 10, LACM 186693 ) . Tirso dive site, north of Three P. Reef, Romblon Island, Philippines, 3 Apr 2017, leg. F. Imhof, 1 specimen 7 mm preserved length, dissected (isolate KM26 , CASIZ 222039 ) . Paliton Wall , Siquijor Island, Viasayas, Philippines, 4 Apr 2016, 1 specimen (isolate KM29 , CASIZ 217329 ) . Rempi , Madang, Papua New Guinea, 19 Nov 2012, 6 m depth, leg. J. Goodheart, 1 specimen 4 mm preserved length (isolate MM86 , CASIZ 191324 ) .

Range

Western Pacific Ocean ( Christa et al. 2014a, Nakano 2018; present study).

Description

External morphology: Body colour cream white to greyish ( Fig. 9C). Head cream white with reticulated dark brown striations; dark brown spots outlining head margin. Rhinophores long, translucent white, with two rows of reticulated dark brown striations throughout; few light yellowish-cream patches present, concentrated near rhinophoral tips. Cerata bulbous, oblong; colour ranges from beige to translucent white, with reticulated dark brown striations; small white papillose structures scattered throughout cerata. Elevated circular clusters scattered throughout cerata; cluster colour varies from whitish to tan to bright yellow; few clusters outlined by circular brown band. Whitish-fuchsia patch and several minute white specks beneath ceratal margin, located on both sides of cerata. Ceratal margin wavy, outlined with pale yellow spots. Foot colour cream white dorsally, with few brown dots scattered throughout; margin outlined by pale yellow band.

Living specimens also exhibited a distinctive swimming behaviour when disturbed, contracting the cerata on alternating sides of the body to create a rowing effect that propelled the animal through the water.

Internal morphology: Radula with 10 teeth in a 7-mm preserved length specimen ( CASIZ 222039) and 12 teeth in a 7 mm long specimen (isolate 09Gua01, LACM 186691), the latter with 7 teeth on descending limb (two broken, including tip of leading tooth), 5 teeth on ascending limb ( Fig. 13A). Teeth narrow, elongate, about 400 µm long, with blunt tips. Two rows of ~27 denticles along either side of tooth. Denticles rhombus shaped, distributed evenly along teeth ( Fig. 13B, D). Ascus with about 11 used teeth ( Fig. 13C). Penis with penial stylet at opening. Penial stylet elongated, curved, cylindrical with slanted oval opening, distinct small hook ( Fig. 11C).

Ecology

Specimens were collected on, and fed upon, Udotea geppiorum Yamada, 1930 in Guam.

Etymology

This species is named in honour of Christine Blackburn, friend and colleague of PK, for her lifetime of work on ocean science and climate policy, including the development of marine protected areas during her time as Assistant Secretary for Conservation and Management at the National Oceanic and Atmospheric Administration; and for letting many trips be taken over by the collection of sea slugs.

Reproduction

Development of specimens in Guam was planktotrophic. Egg masses lacked extra-capsular yolk. One clutch had a mean egg diameter of 52.9 µm ± 1.8 SE (N = 17), while mean egg diameter for a second clutch was 55.6 µm ± 1.8 SE (N = 25). Mean larval shell width measured across the aperture was 134.3 µm ± 3.0 SE (N = 25) for one clutch.

Remarks

All methods of species delimitation analysis distinguished Cyerce blackburnae sp. nov. from the superficially similar Cyerce tutela sp. nov., which were sister taxa in phylogenetic analyses ( Fig. 1A). Cyerce blackburnae sp. nov. and C. tutela sp. nov. share morphological traits, such as bright yellowwhite pustules scattered across cerata and outlining the ceratal margin. Both species have long and straight teeth with recurved rhomboidal denticles. The penial stylet is also long and curved in both species, with a distinct small hook at the tip of the stylet. The species are differentiated by rhinophores that are much more elongated in C. blackburnae sp. nov., and translucent white to beige cerata with reticulated brown spots in C. blackburnae sp. nov. not observed in C. tutela sp. nov. The cerata of C. tutela sp. nov. have a distinct infra-marginal banding pattern of black, fuchsia, and orange that is not observed in specimens of C. blackburnae sp. nov., which have a single fuchsia infra-marginal band on the cerata.

Cyerce blackburnae sp. nov. and C. trowbridgeae sp. nov. both have the reticulated brown striations across the cerata and yellow spots outlining the ceratal margin. However, the cerata in C. trowbridgeae sp. nov. are much darker and lack the fuchsia infra-marginal band that is present in C. blackburnae sp. nov. Cyerce blackburnae sp. nov. is morphologically distinct from all other species of Cyerce , as the only species that has translucent white cerata with reticulated dark brown striations, elevated white pustules and circular clusters, an infra-marginal band of fuchsia, and white overlaying white specks.