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Ruthenica, 2010, vol. 20, No. 2: 117-139, Published December 24, 2010.

©Ruthenica, 2010 http://www.ruthenica.com

Evolution of carnivorous gastropods of the family Costellariidae (Neogastropoda) in the framework of molecular phylogeny
FEDOSOV A.E.1*, KANTOR Yu.I.2*
A.N.Severtzov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninski prospect 33, Moscow 119071, RUSSIA; 1fedosovalexander@gmail.com, 2kantor@malaco-sevin.msk.ru
ABSTRACT. On the basis of the molecular sequences of 12S r-RNA gene of 16 species of Costellariidae the phylogenetic hypothesis is proposed. The anatomy of the foregut and radula of 15 species of the family was studied. The anterior foregut is the most rich in phylogenetically informative characters in Costellariidae and Neogastropoda in general. 6 types of anatomy of the mid-oesophagus have been recognized. They differ in the anatomy of the gland of Leiblein and in the presence/absence and state of development of the glandular tube, formed by stripping off and closure of the glandular folds of mid-oesophagus. On the basis of molecular phylogeny it was demonstrated that the most basal underived type of anterior foregut was found in still unnamed species of the family. It is characterized by unmodified gland of Leiblein opening directly into glandular mid-oesophagus. It is proved that the process of the formation of the glandular tube and transformation of the gland of Leiblein into muscular organ occurred in Costellariidae independently from other lineages of Neogastropoda. The functional morphology of the digestive system is discussed. The most probable source of toxins in costellariids is despite expectations not the gland of Leiblein, but accessory or primary salivary glands.

The family Costellariidae MacDonald, 1860 (= Vexillidae Thiele, 1929) is a large family of tropical Neogastropods, encompassing about 320 Recent species [Robin, Martin, 2004]. The group is relatively well defined conchologically, and is characterized by elongated fusiform shell with strong columellar folds and with normally well developed axial ribs ("costae"), that gave the name to the family. Being popular group among shell collectors, the family attains significant interest from conchological point of view. The latest most comprehensive guide to the family (as well as to the family Mitridae) was published in 2004 [Robin, Martin, 2004], there is a WEB cite dedicated exclusively to "Mitroidea",
* Authors contributed equally to this work.

including Costellariidae (http://mitroidea.eurasiashells.net/). The Philippine representatives of the family have been treated in Poppe [2008]. The family is often erroneously considered as closely related to Mitridae (and included in the same superfamily Mitroidea or Mitracea), although Ponder [1972] convincingly demonstrated the great disparity in anatomy between two families. The family remains poorly studied in terms of anatomy and ecology and just a few contributions have been published [Azuma, 1965; Ponder, 1972; Maes, Raeihle, 1975]. An interesting peculiarity of Costellariidae is the mode of feeding and diet, although very few observations have been published. According to Maes and Raeihle [1975], Mitromica foveata (Sowerby, 1874) [as Thala floridana (Dall, 1883)] feeds on a number of gastropod species, killing the prey with the toxic secretion, which is acting through the undamaged integuments of the prey. Feeding of an unidentified species of Vexillum on a gastropod has been observed by YuK in New Guinea. Finally, Morton and Miller [1968] recorded feeding of Austromitra rubiginosa (Hutton, 1873) on various species of tunicate, both solitary and compound. Nevertheless, Taylor et al. [1980] marked only Gastropoda as a prey item in the diet of Costellariidae. Taxonomy of the family is in the state of flux. The following genera and subgenera are usually recognized within Costellariidae: Costellaria Swainson, 1840 Mitromica S. S. Berry, 1958 Nodicostellaria Petuch, 1987 Pusia Swainson, 1840 Thala H. et H. Adams, 1853 Thaluta Rosenberg et Callomon, 2003 Tosapusia Azuma, 1965 Vexillum RЖding, 1798 Visaya Poppe, Guillot de Suduiraut et Tagaro, 2006 Zierliana Gray, 1847 Except few species (attributed to genera Thaluta, Zierliana and Visaya) the generic position of species


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FIG. 1. Shells of studied specimens of the family Costellariidae. A -- Vexillum plicarium, 42 mm; B -- V. rugosum, 37 mm; C -- V. vulpecula, 43.2 mm; D -- V. albofulvum, 57.5 mm; E -- V. subdivisum, 22.7 mm; F -- V. modestum, 17.4 mm; G -- V. echinatum, 23.1 mm; H -- Costellariidae gen. sp., 32.5 mm; I -- V. militare, 13.3 mm; J -- V. virgo, 14.0 mm; K -- Vexillum costatum, 44.0 mm.


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FIG. 2. Shells of studied specimens of the family Costellariidae A -- Vexillum tusum, 12.0 mm; B -- V. noduliferum, 7.3 mm; C -- V. aureolatum, 8.1 mm; D -- V. interruptum, 5.5 mm; E -- V. diutenerum, 6.6 mm; F -- Pusia salisburyi, 9.0 mm; G -- Pusia rubra, 5.0 mm. FIG. 2. Costellariidae A -- Vexillum tusum, 12,0 ; B -- V. noduliferum, 7,3 ; C -- V. aureolatum, 8,1 ; D -- V. interruptum, 5,5 ; E -- V. diutenerum, 6,6 ; F -- Pusia salisburyi, 9,0 ; G -- Pusia rubra, 5,0 .

as well as the status of some taxa of the genus group is often arbitrarily changed. This occurs mostly due to lack of morphological data not to mention the absence of the available molecular data. The purpose of the current publication is to examine the foregut anatomy (the most variable in Neogastropoda) of a number of species and on the basis of the molecular sequences to reconstruct the phylogeny of some selected species of Costellariidae. This will allow to trace the the major tendencies of the morphological transformations of the foregut.

Materials and methods
Specimens examined Material for the studies was collected during several fieldworks in Philippines (AF) and Vietnam (YK) by SCUBA diving as well as from commercial sources -- fishermen and from "lumun-lumun" collecting nets [Seronay et al., 2010], and in Madagascar (YK) by dredging (Figs. 1, 2). Specimens were relaxed in isotonic solution of MgCl2 and tissue clip (usually the part of the foot) was taken and preserved

. 1. Costellariidae. A -- Vexillum plicarium, 42 ; B -- V. rugosum, 37 ; C -- V. vulpecula, 43,2 ; D -- V. albofulvum, 57,5 ; E -- V. subdivisum, 22,7 ; F -- V. modestum, 17,4 ; G -- V. echinatum, 23,1 ; H -- Costellariidae gen. sp., 32,5 ; I -- V. militare, 13,3 ; J -- V. virgo, 14,0 ; K -- Vexillum costatum, 44,0 .


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Table 1. Examined material and outgroups used in the phylogenetic analysis.
Generic and specific identification Vexillum plicarium Vexillum rugosum Vexillum vulpecula (dark form) Vexillum albofulvum Vexillum modestum Vexillum militare Vexillum echinatum Vexillum virgo Vexillum subdivisum Vexillum costatum Vexillum tusum Vexillum nodiliferum Vexillum aureolatum Vexillum interruptum Vexillum diutenerum Pusia salisburyi Pusia rubra Costellariidae gen. sp. Outgroups Cancellaria cancellata Harpa sp. Mitra lens Trophon plicatus Oliverio M., Modica M.V., 2010 Holford M., Puillandre N., Terryn Y., Cruaud C., Olivera B. Bouchet P., 2009 Oliverio M., Modica M.V., 2010 Barco A., Claremont M., Reid D.G., Houart R., Bouchet P.,Williams S.T., Cruaud C., Couloux A. Oliverio M., 2010 Oliverio M., Modica M.V., 2010 FM999074 EU685491 FM999079 FN677370 Sampling location (or authors for outgroup's sequences) Olango Is, Philippines Olango Is, Philippines Nucnucan Is, Philippines Nucnucan Is, Philippines Marinduque Is, Philippines Balicasag Is, Philippines Olango Is, Philippines Marinduque Is, Philippines Dam Bay, Che Is, Vietnam Hansa Bay, New Guinea Punta Engania, Mactan Island, Philippines Punta Engania, Mactan Island, Philippines Punta Engania, Mactan Island, Philippines Punta Engania, Mactan Island, Philippines Olango Is, Philippines Balicasag Island, Philippines Punta Engania, Mactan Island, Philippines Madagascar, Mozambique Channel, 15°34'S, 45°43'E, 396 m 12S sequence GB accessing N HQ665033 HQ665032 HQ665035 HQ665034 HQ665038 HQ665044 HQ665040 HQ665042 HQ665036 -- HQ665045 HQ665037 HQ665039 HQ665046 HQ665043 HQ665041 -- HQ665047; HQ665048

Latiromitra sp.

FM999085

in 96% ethanol. The body with the shell was preserved in 75% ethanol for anatomical studies. In the case of minute species entire body of some specimens was preserved in 96% ethanol. In laboratory the preserved bodies were dissected for anatomical studies. The radula was cut out of the body and cleaned in diluted solution of bleach (NaOCl), rinsed in distilled water and mounted on clear glass slides, that were glued to the SEM stubs. The radulae were photographed on the TesSCAN TS5130 scanning electron microscope in the A.N.Severtzov Institute of Ecology and Evolution. DNA extraction, amplification and sequencing DNA was extracted from the peace of foot preserved in 96% ethanol, using the Gentra Puregene Tissue (QIAGEN) extraction kit. A fragment of 545 bp of mitochondrian 12S rRNA gene has been amplified using the standard primers [Oliverio, Mariottini, 2001].

Fw: 12SI -- 5' TCG CAG CAG YCG CGG TTA Rw: 12SIII -- 5' AGA GYG RCG GGC GAT GTG T All PCR reactions were set up in the 25ul tubes with the Advanced Tag-polymerase (5-prime). The PCR thermal profile was set up as follows: initial denaturation -- 3 min at 95°, 35 cycles of denaturation (30 sec at 95°), annealing (45 sec at 55°) and extension (45 sec at 68°) with the final elongation phase (5 min at 68°). The PCR products were purified with QIAGEN gel extraction kit. All genes were sequenced in both directions. The GenBank accession numbers of the sequences are summarized in Table 1. Phylogenetic analysis A set of additional 12S sequences of the close families members [Oliverio, Modica, 2010] has been accessed in Genbank (see Table 1). The 12S sequences have been automatically aligned using Clustal


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W2 algorithm available online (http://www.ebi.ac.uk/Tools/msa/clustalw2/), the result of alignment has been inspected by eye and, if needed, manually modified in BioEdit, version 7.0.5.3. The best fitting model of nucleotide substitution has been calculated via Modeltest 7.3 [Posada, Crandall, 2001]. All phylogenetic reconstructions were performed with the Bayesian analysis with the following parameters: two Marcov chains of 3,000,000 generations with the sampling frequency of one tree each 100 generations were run in 8 parallel analyses [Huelsenbeck et al., 2001]. When the log-likelihood scores got stable, a set of strict consensus trees has been constructed, the different proportion from 0 to 20% of trees has been omitted while the consensus tree construction. Abbreviations used in the text and figure captions: af -- additional flap of the penis; AL -- aperture length; aoe -- anterior oesophagus; asg -- accessory salivary gland; bm -- buccal mass; bt -- buccal tube; cbcw -- cut wall of the buccal cavity; cpw -- cut proboscis wall; TW -- central tooth width; dgL -- duct of gland of Leiblein; gL -- gland of Leiblein; gmo -- glandular mid-oesophagus; gpoe -- glandular posterior oesophagus; gt -- glandular tube; nr -- nerve ring; od -- odontophore; odr -- odontophore retractor; ord -- opening to the radular diverticulum; pggL -- poorly glandular gland of Leiblein; poe -- posterior oesophagus; pr -- proboscis; prr -- proboscis retractors; prw -- proboscis wall; rad -- radular membrane; RL -- radular membrane length; rnh -- rhynchodaeum; RW -- radular membrane width; sd -- salivary duct; sg -- salivary gland; SL -- shell length; vd -- vas deferens; vL -- valve of Leiblein.

to the Costellariidae outer taxon, with the PP value of 0.96. Oppositely the family Mitridae, (represented here by Mitra lens) traditionally supposed to be closely related to Costellariidae, appeared far distanced from the costellariid clade. Well supported clade 2 generally corresponds to the genus Vexillum in broad sense and includes 14 of studied species with the type species of the genus, Vexillum plicarium (Linnaeus, 1758). Three costellariid, not included into the clade 2, form two distinct lineages, which represent genus Pusia (P. salisburyi) and one more, likely still undescribed genus, members of which in contrast to all others costellariids studied, inhabit bathyal depths of South African area.

Morphology of the foregut Costellariidae gen. sp.
(Fig. 1H, 4, 5 A-B) Material examined: Madagascar, Mozambique Channel, 15°34'S, 45°43'E, 396 m, F/V Miriky CP 3266, MNHN IM-2009-7427, two specimens dissected, one specimen sequenced (SL 32.5 mm, AL 10.5 mm). Anterior foregut (Fig. 4). Proboscis in contracted state short, comprising ca. 2 mm (0.19 AL, 0.06 SL), cylindrical, slightly tapering. Rhynchodaeum rather thick and muscular. Proboscis occupies about 1/ of rhynchodaeum length. Paired very powerful 2 retractors attached symmetrically to anteriormost ventral part of rhynchodaeum and columellar muscle. Very thin, extremely convoluted buccal tube leads from mouth opening to muscular buccal cavity. Thick walled radular diverticulum branches off buccal cavity and contains deeply retracted odontophore. Loops of buccal tube interconnected with connective tissue fibers, forming rather rigid structure. Powerful branching odontophoral retractor leaves proboscis and follows along oesophagus to pass through nerve ring. It is probably attached to columellar muscle. Anterior oesophagus medium thick within proboscis and attached by numerous muscle fibers to proboscis walls. After leaving proboscis oesophagus sharply narrows and becomes very thin and convoluted, forms rather long loop and follows anteriorly to anteriormost part of rhynchodaeum. It is attached to rhynchodaeum by few connective tissue fibers. Odontophore short (1.22 mm in length), bulbous, situated mostly within proboscis in its contracted state, deeply retracted into radular diverticulum. Subradular cartilages short, fused anteriorly. Radula (Fig. 5 A-B) consists of 60 rows of teeth, 15 nascent, alary processes well developed, about 1/ of radular membrane length. Radular length 2.2 2 mm (0.21 AL) width 220 mkm (2.1% AL). Central

Results
Molecular data analysis
Alignment of 12S sequences for 16 species of Costellariidae and 5 outgroups, gave a dataset of 510 positions in total, of which 234 were constant and 191 variable and parsimony informative. GTR+I+G was found to be the best fitting model of nucleotide substitution. The phylogenetic tree, shown (Fig. 3) is a strict consensus tree, obtained after omitting of 5% of elementary trees. The tree is characterized by relatively low support of most nodes; however some are supported enough that allows some rather general judgments on the phylogeny and relationships of the family Costellariidae. The family Costellariidae -- clade 1, was shown to be monophyletic with the high reliability (the basal node of the family has a PP value of 1). Latiromitra sp. (Ptychatractidae) came out as a closest


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FIG. 3. Strict consensus tree inferred from the 12S gene with Bayesian analysis after 5% of trees have been omitted. The values of posterior probabilities are indicated for each node. . 3. , 12S . 5% . .

tooth medium broad (ca 80 mkm, or 0.76% AL), tricuspid, with strongly curved anterior margin and long lateral flaps. Cusps broad and relatively short, closely spaced, triangular, central being smallest. Lateral tooth sub-triangular, with slightly curved and

blunt tip. No signs of teeth wear observed on radular bending plane. Valve of Leiblein well developed, much broader than oesophagus, pyriform. Mid-oesophagus abruptly narrows to pass through small nerve ring. Pos-


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FIG. 4. Foregut anatomy of Costellariidae gen. sp. A, B -- organs of the body haemocoel: A -- in natural position, B -- extended, salivary gland removed, rhynchocoel open to show the proboscis. C -- opened proboscis. Abbreviatons see p. 121. . 4. Costellariidae gen. sp. A, B -- : A -- , B -- , , , . C -- . : . . 121.

terior to ring mid-oesophagus slightly broadens and is obviously glandular and slightly convoluted. Salivary glands large, massive and bulky, fuse together without visible border. Salivary ducts narrow, enter oesophagus walls shortly after leaving gland in front of valve of Leiblein. Paired large bulbous accessory salivary glands adjoin salivary glands and gland of Leiblein. Their very narrow ducts follow along odontophoral retractor to proboscis base. Gland of Leiblein is large, broadly tubular, bulky, opens via very short duct into mid-oesophagus significantly posterior to nerve ring (position of duct opening is marked by arrow on drawing). Gland whitish in proximal part and light brownish along most of its length.

Pusia salisburyi (Cernohorsky, 1976)
(Fig. 2G; 5 C-D; 6 A-C) Material examined: Balicasag Island, Philippi-

nes, lumun-lumun net, one specimen sequenced, one specimen dissected (SL 9.0 mm, AL 4.3 mm). Anterior foregut (Fig. 6 A-B). Proboscis in contracted state medium long, comprising ca. 1.35 mm (0.31 AL, 0.15 SL), occupies entire rhynchocoel, tapering to tip. Rhynchodaeum thin, transparent. Paired very long but thin proboscis retractors attached to anteriormost part of rhynchodaeum. Thin and nearly straight buccal tube (ca 0.35 mm in length, or 0.25 of proboscis length) leads from mouth opening to muscular buccal cavity. Odontophoral retractor leaves proboscis and follows partially along oesophagus to pass through nerve ring and is probably attached to columellar muscle. Anterior oesophagus relatively thick, after leaving proboscis coiled, forms very long loop and follows anteriorly to middle part of rhynchodaeum, free from rhynchodaeum. Radular diverticulum muscular, thick, occupies posterior 2/3 of proboscis length, lies entirely within proboscis. Odontophore short, deeply retracted into radular diverticulum.


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FIG. 5. Radular (A, B, C, E) and jaw (D, F) morphology. A, B -- Costellariidae gen. sp.; C, D -- Pusia salisburyi; E, F -- P. rubra. . 5. (A, B, C, E) (D, F). A, B -- Costellariidae gen. sp.; C, D -- Pusia salisburyi; E, F -- P. rubra.


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FIG. 6. Foregut anatomy of Pusia salisburyi (A-C) and Pusia rubra (D). A, D -- organs of the body haemocoel in natural position, B -- organs of the body haemocoel extended, salivary gland removed, gland of Leiblein and posterior oesophagus not shown. C -- penis. Abbreviatons see p. 121. . 6. Pusia salisburyi (A-C) Pusia rubra (D). A, D -- . B -- , , . C -- . : . . 121.

Radula (Fig. 5C) consists of 46 rows of teeth, 2 nascent. Radula short, length 450 mkm (0.10 AL), width 125 mkm (2.9% AL). Central tooth broad (ca 60 mkm, or 1.4% AL), with curved anterior margin and numerous (12-13) thin, pointed cusps, gradually elongating from shortest lateral ones to most long, occupying more central position. Central cusp slightly shorter than adjoining cusps. Slight teeth wear observed on anterior rows (lateral cusps broken off). Lateral tooth sub-triangular, with slightly curved and blunt tip. Small horseshoe-shaped jaw (Fig. 5D), rounded in profile, is situated in anterior part of radular diverticulum.

Valve of Leiblein well defined, relatively large, pyriform. Salivary glands small, fuse together without visible border, cover valve of Leiblein and nerve ring. Accessory salivary gland small, cone-shaped, adjoins nerve ring. Mid-oesophagus after passing through nerve ring expands and becomes obviously glandular. Gland of Leiblein large, long, broadly tubular, brownish, opens into posterior portion of glandular part of mid-oesophagus significantly posterior to nerve ring. Posterior to opening of duct of gland of Leiblein oesophagus narrows and becomes nonglandular.


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Penis is very different from other Costellariidae in being club-shaped rather then simple narrowing towards the tip (as in other species) and having additional flap (Fig. 6C).

Pusia rubra (Broderip, 1836)
(Fig. 2G; 5 E-F; 6D) Material examined: Punta Engania, Mactan Island, Philippines, lumun-lumun net, one specimen sequenced, one specimen dissected (SL 5.0 mm, AL 2.25 mm). Anterior foregut (Fig. 6D). Proboscis in contracted state narrow, short, ca. 0.36 mm in length (0.16 AL, 0.07 SL). Proboscis with moderately folded walls, diameter at its base ca. 1.15 mm, at tip 0.3 mm. Rhynchodaeum rather thick, muscular. Paired thin proboscis retractors attached to anteriormost ventral part of rhynchodaeum. Odontophore large, lying entirely outside proboscis. Radular membrane is clearly seen through walls of radular diverticulum by transparency. Radula (Fig. 5E) consists of 37 rows of teeth, 2 nascent. Radula short, length 240 mkm (0.10 AL), width 60 mkm (2.6% AL). Central tooth medium broad (ca. 35 mkm, or 1.5% AL), with slightly curved anterior margin and numerous (12) thin pointed cusps, gradually elongating from shortest lateral ones to most long, occupying more central position. Slight teeth wear can be observed on anterior rows (some cusps broken off). Lateral tooth sub-triangular, with long curved and blunt tip. Small horseshoe-shaped jaw (Fig. 5F), rounded in profile is situated in anterior part of radular diverticulum. Anterior oesophagus thin, convoluted after leaving proboscis, follows anteriorly along rhynchodaeum, and opens into relatively very large valve of Leiblein. Mid-esophagus very thick, convoluted. Gland of Leiblein medium sized, glandular, light brownish, opens into oesophagus by short narrowed duct. Salivary glands medium-sized, separate, not covering valve of Leiblein.

werful retractors attached to anteriormost dorsal part of rhynchodaeum. Buccal tube not pronounced. Powerful branching odontophoral retractor follows along oesophagus to pass through nerve ring. Anterior oesophagus thin, leaving proboscis and following anteriorly along rhynchodaeum, to which it is attached by numerous connective tissue fibers. Radular diverticulum splits from anterior oesophagus near proboscis tip. Odontophore deeply retracted, ca. 2 mm in length. Cartilages separate, connected anteriorly by muscular sheath, shorter or slightly longer than radular membrane. Radula (Fig. 8A) consists of 46 rows of teeth, 2 nascent. Radula short, length 1.25 mm (0.11 AL), width 290 mkm (2.7% AL). Central tooth medium broad (ca. 175 mkm, or 1.6% AL), with slightly curved anterior margin and numerous (15-16) thin pointed cusps, gradually elongating from shortest lateral ones to most long and thick central ones. Rather strong teeth wear can be observed on anterior rows (some cusps on central teeth broken off and tips of lateral ones worn off). Lateral tooth hook-like, with narrow base and long curved pointed tip. Valve of Leiblein small, distinct, with circle of mucous cells seen through its walls. Salivary glands large, massive and bulky, fused, covering nerve ring. Salivary ducts narrow, enter oesophagus walls shortly after leaving gland, convoluted. Accessory salivary glands not found. Gland of Leiblein medium-sized, tubular and convoluted, narrow, with semi-transparent walls, brownish, tapering to narrow tip. Gland duct opens into glandular tube formed by stripped off dorsal folds of mid-oesophagus. Glandular tube whitish, moderately convoluted, forming funnel-shaped expansion, embracing oesophagus. Tube opens into oesophagus at some distance posterior to small nerve ring.

Vexillum noduliferum (A.Adams, 1853)
(Fig. 2B; 9A; 10C) Material examined: Punta Engania, Mactan Island, Philippines, lumun-lumun net, one specimen sequenced, one specimen dissected (SL 7.3 mm, AL 3.6 mm). Anterior foregut (Fig. 9A). Proboscis in contracted state bended within rhynchodaeum, ca. 0.8 mm in length (0.22 AL, 0.10 SL), tapering to its tip, 0.09 mm in diameter at base and 0.05 mm at tip. Rhynchodaeum very thin and transparent. Paired thin proboscis retractors attached to anteriormost dorsal part of rhynchodaeum. Odontophoral retractor follows along oesophagus to pass through nerve ring, and attached to columellar muscle. Odontophore occupies posterior 1/5 of radular diverticulum, radular membrane slightly protruding beyond proboscis. Anterior oesophagus

Vexillum subdivisum (Gmelin, 1791)
(Fig. 1E; 7A; 8A) Material examined: Dam Bay, Che Island, southern Vietnam, mangroves, one specimen sequenced, 2 specimen dissected (SL 20.5 mm, AL 10.7 mm -- radula illustrated), SL 22.7 mm, AL 11.7 mm -- anatomy illustrated). Anterior foregut (Fig. 7A). Proboscis in contracted state narrow, medium long, about 3.7 mm in length (0.31 AL, 0.16 SL), gradually narrowing toward tip, with moderately folded walls. Rhynchodaeum rather thick and muscular. Paired very po-


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FIG. 7. Foregut anatomy of Vexillum subdivisum (A) and V. virgo (B). A -- organs of the body haemocoel extended, left salivary gland removed, B -- organs of the body haemocoel in natural position, rhynchocoel open to show the proboscis. Abbreviatons see p. 121. . 7. Vexillum subdivisum (A) V. virgo (B). A -- , , , . B -- . : . . 121.

thin, convoluted after leaving proboscis, forms a loop and follows anteriorly along rhynchodaeum. Radula (Fig. 10C) consists of 53 rows of teeth, 3 nascent. Radula short, length 290 mkm (0.08 AL), narrow, width 55 mkm (1.5% AL). Central tooth medium narrow (ca 35 mkm, or 1.0% AL), with slightly curved anterior margin and 7 triangular pointed cusps of sub-equal length. No signs of teeth wear observed. Lateral tooth hook-like, with narrow base and long strongly curved pointed tip. Alary processes of membrane long, comprising about 1/2 of the radular length. Valve of Leiblein obsolete. Salivary glands large, massive and bulky, fused, covering nerve ring. Accessory salivary not found. Gland of Leiblein small, conical, with muscular walls, opens into thick, relatively short and strongly convoluted glandular tube. Tube opens into oesophagus immediately posterior to massive nerve ring.

Vexillum modestum (Reeve, 1845)
(Fig. 1F; 10B) Material examined: Marinduque Island, Philip-

pines, from fishermen, one specimen sequenced, one specimen dissected (SL 17.4 mm, AL 6.5 mm). Anterior foregut. In general morphology rather similar to V. noduliferum. It differs in having much longer, straight, rather thick proboscis (2.8 mm in length, 0.43 AL, 0.16 SL), only slightly tapering to its tip, 0.9 mm in diameter at base and 0.3 mm at tip. Gland of Leiblein relatively slightly larger, sausage-shaped rather then conical, opens into slightly longer glandular tube. Odontophore lies within proboscis, about 0.95 mm in length, deeply retracted into radular diverticulum, which itself 1.65 mm in length. Subradular cartilages paired, fused anteriorly and free posteriorly. Buccal tube medium thin, slightly convoluted, and not long, in extended state about 1/4 of the proboscis length. Radula (Fig. 10B) consists of 66 rows of teeth, 14 nascent. Radula short, length ca. 750 mkm (0.12 AL), width 145 mkm (2.2% AL). Central tooth medium broad (ca. 80 mkm, or 1.2% AL), with slightly and evenly curved anterior margin and 10 thin pointed cusps of sub-equal length. No teeth wear can


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FIG. 8. Radular morphology. A -- Vexillum subdivisum; B, C -- V. albofulvum; D -- V. rugosum; E -- V. plicarium; F -- V. vulpecula. . 8. . A -- Vexillum subdivisum; B, C -- V. albofulvum; D -- V. rugosum; E -- V. plicarium; F -- V. vulpecula.


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FIG. 9. Foregut anatomy of Vexillum noduliferum (A), V. militare (B) and V. plicarium (C). A -- organs of the body haemocoel in natural position, left salivary gland removed. B, C -- organs of the body haemocoel extended, in B rhynchocoel open to show the proboscis. Abbreviatons see p. 121. . 9. Vexillum noduliferum (A), V. militare (B) V. plicarium (C). A -- . B, C -- , . B , . : . . 121.

be observed on anterior rows. Lateral tooth hooklike, with narrow base and long pointed tip curved near the summit. Alary processes of the membrane long, comprising about 1/2 of the radular length.

Vexillum militare (Reeve, 1845)
(Fig. 1I; 9B; 10A) Material examined: Balicasag Island, Philippines, lumun-lumun net, one specimen sequenced and dissected (SL 13.3 mm, AL 6.6 mm). Anterior foregut (Fig. 9B). Proboscis in contracted state long, comprising ca. 2.25 mm (0.34 AL, 0.17 SL), occupies entire rhynchocoel. Rhynchodaeum thin, transparent. Paired thin retractors attached to middle ventral part of rhynchodaeum. Thin and strongly convoluted buccal tube leads from mouth opening to muscular buccal cavity. It forms not long rigid structure, impossible to extend. Odontophoral retractor leaves proboscis and follows along oesophagus to pass through nerve ring.

Anterior oesophagus relatively thick, coiled after leaving proboscis, forms short loop and follows anteriorly to middle part of rhynchodaeum and attached to rhynchodaeum by numerous connective tissue fibers. Radular diverticulum muscular and thick, lies entirely within the proboscis in its posterior half. Odontophore short, bulbous. Subradular cartilages short, fused anteriorly. Radula (Fig. 10A) consists of 38 rows of teeth, 6 nascent. Radula short, length ca. 600 mkm (0.09 AL), width 155 mkm (2.3% AL). Central tooth medium broad (ca. 90 mkm, or 1.3% AL), with slightly and evenly curved anterior margin and short lateral flaps. Central tooth with 9 thin, pointed cusps of sub-equal length. Additional much smaller cusp appear as most lateral on some teeth. Although two central teeth had broken cusps, this is probably artifact, since anteriormost rows, exposed on bending plane, were intact. Lateral tooth hook-like, with relatively broad base and blunt tip curved near summit.


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Alary processes of membrane long, comprising more than 1/2 of radular length. Valve of Leiblein well defined although small, pyriform. Salivary glands medium-sized, fuse together without visible border. Accessory salivary gland not found. Mid-oesophagus after passing through nerve ring greatly expands and becomes obviously glandular. Gland of Leiblein small, narrow, conical, with muscular walls. It opens into rather short, slightly coiled glandular tube. Tube opens into posterior portion of glandular part of mid-oesophagus significantly posterior to nerve ring. Posterior to opening of glandular tube oesophagus sharply narrows.

Gland of Leiblein large, convoluted, with partitions seen through its walls, terminating in small ampulla. It opens into long and massive convoluted glandular tube, uniform yellowish tan. Tube opens into oesophagus immediately posterior to nerve ring.

Vexillum diutenerum (Hervier, 1898)
(Fig. 2E; 10D) Material examined: Olango Island, Philippines, from fishermen, one specimen sequenced, one specimen dissected (SL 6.6 mm, AL 2.4 mm). Anterior foregut. In general morphology very similar to V. noduliferum. It differs in having much longer straight, rather thick proboscis (1.15 mm in length, 0.48 AL, 0.17 SL), only slightly tapering to tip. Odontophore lies within proboscis, about 0.27 mm in length, deeply retracted into r