Cyerce nicholasi, Moreno & Rico & Middlebrooks & Medrano & Valdés & Krug, 2024

Moreno, Karina, Rico, Diane M., Middlebrooks, Michael, Medrano, Sabrina, Valdés, Ángel A. & Krug, Patrick J., 2024, A cryptic radiation of Caribbean sea slugs revealed by integrative analysis: Cyerce ‘ antillensis’ (Sacoglossa: Caliphyllidae) is six distinct species, Zoological Journal of the Linnean Society 200 (4), pp. 940-979 : 961-964

publication ID

https://doi.org/ 10.1093/zoolinnean/zlad111

publication LSID

lsid:zoobank.org:pub:E8CC81A3-E625-4C48-B783-29AA9BFC83C3C

DOI

https://doi.org/10.5281/zenodo.11267563

persistent identifier

https://treatment.plazi.org/id/03C287FB-FFAF-FFC6-F869-4041FC3D2332

treatment provided by

Plazi

scientific name

Cyerce nicholasi
status

sp. nov.

Cyerce nicholasi View in CoL sp.nov.

( Figs 1–5 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 , 8A View Figure 8 , 12 View Figure 12 , 13 View Figure 13 )

ZooBank registration: lsid:zoobank.org:act: DA9D52FA-9103- 4430-8B46-C66C1F7D1F86

Cyerce antillensis View in CoL – Clark and Defreese 1987: 259–279; Clark 1994: 906; Krug et al. 2015: 989–991; Goodheart et al. 2016: 23–25.

Type material

Holotype: Little San Salvador , Bahamas, Caribbean Sea, July 2007, 4 mm preserved length, ( LACM 3842 View Materials ; isolate 07 LSS02 ).

Additional material examined

Bimini, Caribbean Sea , July 2010, one specimen preserved, isolate 10Bim03 .

Range

Bahamas, Dominica, Panama (present study).

Description

External morphology: Body colour pale yellow–green; notum flecked with minute burgundy or brown specks ( Fig. 12 View Figure 12 ). Head white to pale green, flecked with burgundy or brown speckles. Small burgundy patch between eyes, extending as thin line up to the base of each rhinophore, giving appearance of arched eyebrows. Rhinophores and tentacles smooth, translucent, frosted with white patches and brown specks.

Pericardium round, heavily papillose; brown to burgundy ground colour, with white papillae ( Fig. 12B, C View Figure 12 ). Anal papilla white, anterior and to the right of pericardium. Dorsal vessels capped in grey when first extending from the pericardial sac; paired posterior vessels running length of notum to base of pointed tail, with short side branches emerging to connect to cerata along body margin ( Fig. 12B, C View Figure 12 ). Lateral vessels not clearly visible. Cerata flat, narrow, elongated; translucent, with large white patches scattered across surface.Small burgundy or brown oval-shaped patch at base of ceras; larger, brown oval patch surrounded by fine yellow ring located near tip of ceras ( Fig. 12A–C View Figure 12 ). Ceratal margin extending into crenulate white rim of rounded, finger-like protrusions. On some specimens, outer face of cerata covered in tan to brown patches and with long brown streaks ( Fig. 12D View Figure 12 ).

Internal morphology: One specimen (4 mm body length) with 15 radular teeth, 8 on the ascending limb and 7 on the descending limb, and ≥ 17 pre-radular teeth in the ascus ( LACM 3842 View Materials , isolate 07 LSS02 ); leading tooth was 145 μm long. Second specimen (2 mm body length) with 13 teeth, 4 on the ascending limb and 9 on the descending limb, and a dense jumble of pre-radular teeth in the ascus (isolate 10 BIM03 View Materials ); leading tooth with damaged tip, next tooth on ascending limb was 115 μm long ( Fig. 13A–C View Figure 13 ). Teeth of moderate depth, slightly angled down towards blunt tip. Cutting edge with row of 10 rectangular denticles distributed evenly along either side of tooth, each 3 μm wide ( Fig. 13B View Figure 13 ) .

Penis with long, curved stylet with oval opening ( Fig. 8A View Figure 8 ). Stylet measuring 175 μm long and 7 μm wide at opening (isolate 10 BIM 03).

Ecology

Specimens were collected on Pe. dumetosus in Sweetings Cay and Great Stirrup Cay, Bahamas and in Bocas del Toro, Panama. Slugs fed on Pe. dumetosus in the laboratory. Both specimens from Bimini, Bahamas were collected from R. phoenix , an alga closely related to Penicillus , which is also occasionally used as a host by the Penicillus -specialist E. papillosa ( Krug et al. 2016) . The lone specimen from San Salvador, Bahamas was collected from H. goreaui beneath a shaded coral overhang.

Reproduction

Data were obtained for one clutch laid by a specimen collected from Penicillus in Sweetings Cay, Bahamas in 2004. The egg mass lacked extracapsular yolk and had one embryo per capsule. The mean ± SEM larval shell width across the aperture was 308.3 ± 4.3 μm (N = 7) for one clutch, in the size range for lecithotrophic species in Sacoglossa ( Krug et al. 2015). Larvae had the morphological characteristics of lecithotrophy, including an enlarged propodium, eyespots and crawling behaviour upon hatching, although no spontaneous metamorphosis was observed.

Etymology

Named in honour of Nicholas, the pet boa constrictor of P.J.K., who waited patiently for his return from many field trips over 34 years. The bifid rhinophores of Cyerce are reminiscent of Nick’s forked tongue, and boas radiated in the Caribbean, as did this lineage of Cyerce , making a fitting namesake for a lifelong companion.

Remarks

Cyerce nicholasi View in CoL has probably been widely confused with C. antillensis Engel, 1927 View in CoL given the many reports of C. antillensis View in CoL - like specimens feeding on Penicillus View in CoL . Both species share a wide range spanning the Bahamas, Dominica and Panama; however, no specimens of C. nicholasi View in CoL have yet been sampled in Florida, where C. antillensis View in CoL and at least two other complex members occur. Algal host use easily distinguished the two common species: C. nicholasi View in CoL feeds primarily on Pe. dumetosus and the related alga R. phoenix , whereas C. antillensis View in CoL specializes on H. opuntia . However, given that multiple species in the C. antillensis View in CoL complex feed on Penicillus View in CoL and Rhipocephalus View in CoL , host use is not a diagnostic character for C. nicholasi View in CoL .

Limited developmental data also suggest that C. nicholasi View in CoL can be distinguished from C.antillensis View in CoL and some other complex members by larval type. Larval shell size for Sweetings Cay specimens of C. nicholasi View in CoL indicates lecithotrophic development, whereas C. antillensis View in CoL and C. piercei View in CoL were both planktotrophic and also overlap with C. nicholasi View in CoL in the Bahamas. Development mode may thus be a potentially useful character for differentiating the species where they are sympatric; however, given that poecilogony occurs in Caribbean sacoglossans, larval type can be unreliable for identifying a species without intensive population-level sampling ( Krug 2009, Ellingson and Krug 2016). The high degree of population genetic structure in C. nicholasi View in CoL (lecithotrophic) is consistent with the predicted reduction in dispersal potential conferred by short-lived lecithotrophic larvae, in comparison to the lack of structure in C. antillensis View in CoL (planktotrophic).

Externally, the shape and appearance of cerata and the body colour distinguish C. nicholasi from C. antillensis , while the penial stylet is entirely different in shape and size. Radular tooth morphology is also notably different. In C. nicholasi , teeth are much shallower, more pointed yet blunt at the very tip, and have square, flat-edged denticles; in comparison, in C. antillensis the teeth are rhomboid, deeper, taper to a point and have backcurving pointed denticles.

Distinguishing C. nicholasi from the remaining four species in the C. antillensis complex is more challenging, although all were genetically distinct. The long, curved penial stylet of C. nicholasi was the most diagnostic character, clearly different from the short, straight stylet of C. ellingsonorum , the short, curved stylet of C. piercei or the wide, curved stylet of C. willetteorum . Radular morphology also differentiates C. nicholasi (straight tooth, blunt tip, small square denticles) from C. piercei and C. browneveorum (angled tooth, tapered tip, denticles angled outwards), C. ellingsonorum (more teeth, large square denticles) and C. willetteorum (irregularly angled and shaped denticles) ( Table 5 View Table 5 ).

BIM

Belarus National Academy of Sciences

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Order

Sacoglossa

Family

Hermaeidae

Genus

Cyerce

Loc

Cyerce nicholasi

Moreno, Karina, Rico, Diane M., Middlebrooks, Michael, Medrano, Sabrina, Valdés, Ángel A. & Krug, Patrick J. 2024
2024
Loc

Cyerce antillensis

Goodheart JA & Ellingson RA & Vital XG 2016: 23
Krug PJ & Vendetti JE & Ellingson RA 2015: 989
Clark KB 1994: 906
Clark KB & DeFreese D 1987: 259
1987
GBIF Dataset (for parent article) Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF