l~ccords of the \:Ycstcm A/lstrallal/ I'vl/lsC/l1l1 Supplement No 69 111~117 (2006)

A redescription of Facelina stearnsi Cockerell, 1901 (Nudibranchia:Aeolidacea: Facelinidae) with a reassignment of its generic placement

Jamie M. Chan and Terrence M. Gosliner

Department of Invertebrate Zoology and Geology, California Academy of Sciences875 lloward Street, San Francisco, California 94103, USA

Abstract - Facelina steamsi Cockerell, 1901 is known from Santa Cruz (Nelson1986) to La Jolla, California (Behrens 1991). Several preserved specimens areexamined and compared with the original description and other species inthe genus AlIstraeolis Burn, 1962. The coloration, reproductive and radularmorphology are described in detail for the first time using SEM, compoundmicroscopy and photographs of live specimens. Observation of several newmorphological and anatomical characters suggests a reassignment of Facelinastcamsi to the genus AlIstraeolis Burn, 1962.

INTRODUCTION

According to Miller (1974) the Facelinidae isdivided into subfamilies based on the cera talarrangement. Genera are further divided on thebasis of penial morphology. Cockerell (1901)described Facelina stearnsi from a specimen collectedin San Pedro, California. Cockerell's descriptionconsisted of observations of the external andradular morphology. No details were given for anyof the internal organ anatomy. There were no platesor drawings in the original description. The typematerial has not been located in any Americanmuseum and a neotype is here designated.Additional records of this species have beenpublished by Eliot (1907), O'Donoghue (1926),Steinberg (1961), Marcus and Marcus (1967), andNelson (1986) but only two publications,O'Donoghue (1927) and McDonald (1983), includedline drawings of radular teeth and one jaw part.The present study examines several specimens ofFacelina stearnsi and compares them to previousdescriptions.

MATERIAL AND METHODS

Material was obtained from the Department ofInvertebrate Zoology and Geology, CaliforniaAcademy of Sciences, San Francisco (CASIZ). Thespecimens were dissected by ventral or dorsalincision. Their internal features were examined anddrawn under a dissecting microscope with a cameralucida. Systematically important soft parts werecritical point dried for SEM. Special attention waspaid to the morphology of the reproductive system,digestive system and central nervous system. Thepenial hooks and jaw plates were prepared forexamination by SEM. Radulae were extracted andexamined using SEM or compound microscopy.

Features of living animals were recorded fromphotographs or notes of collectors.

Austraeolis stearnsi (Cockerell, 1901)

Facelina stearnsi Cockerell, 1901: 86. Behrens, 1991:97Fig. 206.

Phidiana stearnsi McDonald, 1983: 203-204 figure111.

AlIstraeolis stearnsi (Cockerell) comb. novo

Material examinedNeotype: CASIZ 171165, one specimen 2 cm in

length. CASIZ 89095 fifteen preserved specimens,three dissected, Morro Bay, San Luis ObispoCounty, California, United States of America, 12 mdepth, 17 July 1993, Mike Behrens, lengths 2.5 cm, 3cm, 2cm (preserved dissected specimens).

DistributionThis species is known from Santa Cruz (Nelson,

1986) to La Jolla, California (Behrens, 1991).

EtymologyThis species was named after Or. Robert Edward

Carter Stearns.

External MorphologyThe body is elongate and slender, with a trailing

posterior end of the foot (Figure 1). The anteriormargin of the foot and tentaculiform foot cornersare bilabiate and slightly notched. Body color canrange from translucent clear to a pink or purplecast. The moderately long cerata are cylindrical andtaper distally. The tightly grouped cerata arearranged in eight arches on each side of the body

112

Figure 1 Photograph of living specimen of Austraeolisstearnsi (CockerelJ, 1901) photo by T. Gosliner.

(Figure 2A). The largest arch is the most anterior oneach side and consists of 28-30 cerata. The cerataare translucent from the base terminating with abroad band of orange/vermillion to yellow andtipped with white. The rhinophores are annulateand have 1D-15 annulae each. The upper half of therhinophores transition from yellow to orange/vermillion, with a white tip. Both the oral tentaclesand the tentacular anterior foot corners have anorange mid-region and an opaque white tip. Thelong tapering oral tentacles also have a white orcream line that runs along the dorsal side and thenacross the head to the base of the rhinophores. Theline is often orange/yellow toward the base of therhinophore. There are irregular spots of orange/vermillion behind the rhinophores and betweeneach group of cerata. A white to orange line runsdorsally from the posterior cerata cluster to the tipof the foot. The anus is located ventral and withinthe second cluster of cerata. The genital aperture is

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J.M. Chan, T.M. Gosliner

located below the anterior limb of the first ceratalarch.

AnatomyThe radula formula is 24-25xO.1.0 (Figure 3A) for

three examined specimens. The rachidian toothconsists of a single large incurved hook-like toothflanked by 4-6 smaller denticles on each side(Figure 3A, 3B). The jaws have a tan-brown hue tothem (Figure 2B, 3C). There is a thickened tooth­like projection at the anterior corner of each jaw.There are 18-20 denticles on the masticatory edgeof each jaw. Some of the larger denticles havedistinct papillae on the top (Figure 3D).

The ampulla is long and curved (Figure 2C). Theampulla bifurcates to the oviduct and the vasdeferens. The oviduct is one quarter the length ofampulla and leads to a large spherical receptaculumseminis. The receptaculum seminis connects to thefemale gland mass via a thin duct half the size ofthe oviduct. The female gland mass is composed ofa large mucous gland, a small albumen gland and aconvoluted membrane gland. The vas deferens isthick, twice diameter and half the length of theampulla. The vas deferens curves into a fibrouspenial sheath. The penis is armed with a ring of 20spines (Figure 20, 3E, 3F). The spines are papillatein shape.

DiscussionCockerell (1901) described the radula of Facelina

stearnsi as being very similar to Hermissendacrassicornis (Eschscholtz, 1831), but Facelinastearnsi can be distinguished from H. crassicornisby the absence of minute denticles lining the ventralside of the primary cusp of the rachidian tooth. Therachidian tooth of H. crassicornis is more concavethan Facelina stearnsi. Cockerell made noobservation of the jaws or reproductive system.

Eliot (1907) described a Facelina sp. from apreserved specimen collected in Dunedin Harbour,

ew Zealand. Eliot described the Facelina sp. ashaving a similar radula and jaw morphology toFacelina stearnsi. The ceratal arrangement of thisspecies was not described. 0 observation was madeof the reproductive system other than the presenceof penial armature. Data were not collected about thecolor and appearance of the specimen in its livingstate. The reported range of Facelina stearnsi is fromSanta Cruz to La Jolla, California (Bemens, 1991). Itis unlikely that Eliot's Facelina sp. is Facelina stearnsibased on the collection locality and thebiogeographical distinctions of California and NewZealand marine biotas.

O'Donoghue (1927) described a preservedspecimen of Facelina stearnsi from Laguna Beach,California. The external morphology and raduladescribed agree with the description by Cockerel!.O'Donoghue observed that the jaw had a

A

a 9

B

c

2 arr"an,geml:nt. abbreviatIOns:bar lmm;

114 J.M. Chan, T.M. Gosliner

Figure 3 Scanning Electron Micrographs of Allstraeolis steamsi (Cockerell, 1901) (CASIZ 89095). A, Radula, scale bar =100Jlm; B, Radula close up, scale bar = 20Jlm; C, Jaw, scale bar = lOOJlm; D, Jaw close up, scale bar = lOJlm; E,Penis and detail of penial papillae, scale bar =20Jlm, Insert scale bar =3Jlm; F, Detail of penial papillae, scalebar = lOJlm.

Based on Miller's diagnosis and original genericdescriptions the penis of Face/ina steamsi is mostsimilar to the Favorininae genera Amanda (Macnae1954) and Austraeolis Bum 1962 (Table 1). Amandaarmata is described as having a penis with a sub­apical circle of tiny hooks. The rhinophores areannulate with 3-4 incomplete rings compared to10-15 annulae in Facelina steamsi. The radula isuniserate with denticles and the jaw is denticulate.The description of the reproductive system of A.armata, the type species, indicates penial spines that

are very incurved and terminate in a fine point. Thepenial spines of Face/ina steamsi are shorter andmore papillate in shape. Other differences includedramatically different color pattern and moresparsely arranged cerata in Face/ina armata.

The genus Shinanoeolis Baba, 1965 is described ashaving a more similar penial shape and armature toFace/ina steamsi. Based on the original typedescription Cllthona emllrai (Baba 1937) forShil1anoeolis the external features and radula do notagree with the current description of Facelina

A comparison of the anatomical characteristics of Amanda armata Macnae, 1954, Austraeolis ornata Angas, 1864, and Austraeolis stearnsi (Cockerell, 1901).Table 1

Specie/Genus Amanda armata Austraeolis benthicola Austraeolis catina Austraeolis ornata

(Macnae, 1954 ) (Burn, 1966) (Marcus & Marcus, 1964) (Angas, 1864)

Rhinophores Annulate Annulate with Annulate and have up Annulate

Rhinophores 5 annulae each to 12 annulae each Rhinophores

Jaw 16 dentides on the Ovate jaw, with 30 conical, knobbed dentides 20 dentides on the

masticatory edge 30 irregularly on the masticatory masticatory edge

of each jaw rounded dentides edge of each jaw of each jaw

Austraeolis westeralis(Burn, 1966)

Annulate with 12or more annulae each

Subovate jaw with20 large conicaldentides on thelower edge of

each jaw and numeroussmall serrrations above18-20 dentides on the

masticatory edgeof each jaw

Facelina stearnsi(Present study)

Annulate and have10-15 annulae each

:;.::lt1lp..t1ltIln...

>8'-00

::lo.....~'"~"0::ll:l

'"~l:l

~'""0(')on

?r~....\Do....

Radula

Penis

16-17xO.1.0Radula uniserate withprominent cusp and

strong lateral dentides

sub-apical cirdeof tiny hooks

28xO.1.0Long slender teeth

with a large taperingcusp and 2-3

dentides each side

conical and short, tipwith a shallow rim

on one side that formsa lip from which the vas

deferens opens

23xO.1.0The cusp of the

tooth is prominent,flanked by 4-6

slightly curved dentides

cynlindrical andcurved upward. Endsin a disc whose edge

is beset with 10broad warts, each

bearing a tiny spine. Twofurther warts on the surfaceof the disc also with spines.

20-22xO.1.0Prominent central

cusp with 4-5lateral dentides

finger-like andcurved forward,

transversely demarkedby muscular ridges;glans beset with a

cirdet of six minutefleshy filaments,

without any traceof chitonous orspicular hooks

23xO.1.0A tapering cusp with4-5 dentides each side

Similar to Austraeolisornata but is

shorter and broader

24-25xO.1.0Singlelargeincurved

hook-like toothflanked by 4-6

smaller dentideson each side

armed with a ring of 20spines. The spines are

papillate in shape

........(Jl

116

stearnsi. Distinctive differences such as smoothrhinophores, color pattern and a rachidian toothbearing numerous small indistinct denticles suggestits synonymy with Hermissenda crassicornis(Eschscholtz, 1831).

The penis, radula, and jaw structure of Facelinastearnsi agree most closely with species in the genusAustraeolis Bum 1962. Austraeolis is described ashaving a conical penis with a fleshy lobe(sometimes papillate) or short fleshy processes orwarts, a rachidian with 4-5 lateral denticles on eachside, and a denticulate jaw. There are five describedspecies of Austraeolis; A. ornata Bum, 1962, A. fuciaBum, 1962, A. benthicola, Bum 1966, A. westeralis,Bum, 1966 and A. catina Marcus and Marcus, 1967.Austraeolis ornata, A. fucia, A. benthicola and A.westeralis are known from Australia. Austraeoliscatina is found in the Caribbean.

Bum made observations of the external, internal,radular and penial morphology of A. ornata. Thepenis is described as ' ..... .finger-like and curvedforward, transversely demarked by muscularridges; glans beset with a circlet of six minute fleshyfilaments, without any trace of chitonous or spicularhooks.' This is in contrast to the more than 20 spinespresent in Facelina stearnsi. The radula formula is20-22xO.1.0. The jaw has a denticulate masticatoryborder. The body color can range in color from apale translucent yellow to an intense bright orange.There are usually white patches and spots on thebody often bluish or iridescent. The rhinophoreshave some prominent folds or ridges and areusually tipped with white rather than the welldeveloped annulae found in Facelina stearnsi. Thedigestive gland within the cerata ranges in colorfrom a pale yellow to a dark brown. (Rudman,2000).

Austraeolis fucia is described from a singlespecimen collected in Queenscliff, Australia.Observations were made of the external andradular morphology. There are no illustrations ofthe internal anatomy. The radula formula is19xO.1.0. Burn noted that the morphology ofAustraeolis fucia is distinct from A. ornata by 'havingfewer annulae on the rhinophores'. The body coloris creamy-white, the cerata are transparent, with theinner digestive gland a creamy-white color. In 1966,Bum noted that Austraeolis fucia is most likely aspecimen of Facelina hartleyi Bum, 1962.

Austraeolis benthicola is described from a singlespecimen collected in New South Wales. Austraeolisbenthicola has a conical and short penis, at its tip is ashallow rim on one side that forms a lip from whichthe vas deferens opens. The radula formula is28xO.1.0. Austraeolis benthicola is unique from allother Austraeolis species in having wide footmargins, ovate jaws, slender radular teeth and anapical rim of the penis. It is the first deep-wateraeolid recorded from Australia.

J.M. Chan, T.M. Gosliner

Austraeolis westralis is described from sevenspecimens collected in Western Australia.Austraeolis westralis has an internal and externalanatomy similar to A. ornata. Austraeolis westralisdiffers from A. ornata in possessing a narrowercoiled prostatic vas deferens, larger outer vasdeferens, shorter, broader penis with numerousdenticle-like fleshy serrations at the tip and a moreelongate spermatheca. Due to the lack of knowledgeon opisthobranch fauna in southern Australia, Bumconsiders that Austraeolis westralis might be anextreme form of A. ornata.

Austraeolis catina is described from twopreserved species. Observations were made of theexternal and radular morphology. Austraeoliscatina differs from the other species by the absenceof cuticular hooks on the six filaments of the penis,9 rhinophoral rings, 20 denticles on themasticatory border of the jaw and a radularformula of 20-22xO.1.0. Body color is described as'transparent greyish .. with brown marks on sideof head and middle of rhinophores' and withwhite speckling on skin, concentrated in someparts such as middle of head and tentacles'.Facelina stearnsi can be distinguished from otherspecies of Austraeolis by its external and penialmorphology.

Based on this study, the following characteristicsappear to be consistent for all Facelina stearnsispecimens:1. Oral tentacles have a white or cream line that

runs along the dorsal side and then across thehead to the base of the rhinophores. The line isoften orange/yellow toward the base of therhinophore.

2. Irregular spots of orange/vermillion behind therhinophores and between each group of cerata.

3. Cerata arranged in eight arches3. Anus is located ventral and anterior to the

second cluster of cerata.4. The genital aperture is located below the anterior

limb of the first ceratal arch.5. The penis is armed with a ring of papillate

spines.In conclusion, we suggest that Facelina stearnsi is

more properly placed in the genus Austraeolis dueto the arrangement of cerata and its penialarmature. A thorough study of the Facelinidae isnecessary to establish phylogenetic relationshipsand determine monophyletic clades.

ACKNOWLEDGEMENTS

This research was supported by the CaliforniaAcademy of Sciences, the NSF PEET grant #0329054and a UNITAS Student Travel Grant that permittedthe senior author to attend the World Congress ofMalacology in Perth, Australia July, 2004.

Redescription of Facelilla stearnsi Cockerell, 1901

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