VALENCINURA JAMBIO
SP. NOV.
( FIGS 2D, E
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, 4D
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)
Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: E998BBEE-F62E-4D2A-9C27-DE7A889056B4.
Material examined:
Holotype,
ICHUM 6305
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, extracted total DNA (no morphological voucher remains); 19 February 2014, dredged at station 3 of the 2 nd JAMBIO
Coastal Organism Joint Survey
(Nakano etal., 2015), off Misaki, Sagami Bay, Kanagawa (between 35°08′48″N, 139°34′41″E, 87 m depth and 35°08′38″N, 139°34′35″E, 89 m depth), Japan, collected by H. Kajihara.
GoogleMaps
Sequences: From the
holotype:
LC178643
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, 28S (2104 bp)
;
LC178692
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, 16S (507 bp)
;
LC190964
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, COI (476 bp)
.
Etymology: The new specific name is a noun in apposition, from the acronym for the Japanese Association for Marine Biology.
Description: Anterior fragment, 2 cm long, 1 mm wide; anteriorly circular in cross-section, anterior 9 mm pure white; posteriorly flattened dorsoventrally, pinkish in colour ( Fig. 2D
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); rhynchocoel (or proboscis) yellowish ( Fig. 2E
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). Head pointed, not demarcated from body, but pair of transverse cephalic furrows present just anterior to mouth; no secondary furrows. Proboscis pore mid-ventral, opening between cephalic tip and mouth ( Fig. 4D
View Figure 4
).
Distribution: Known only from the type locality, Sagami Bay, Japan (present study).
Remarks: Our generic assignment of
Valencinura jambio
depends almost entirely on the phylogenetic closeness of this taxon to
Vu. bahusiensis
in our analyses ( Fig. 1
View Figure 1
) and should be regarded as tentative and provisional, because the species could equally likely belong to
Valencinia
or
Valencinina
based on internal morphology, data that are lacking for this species. In
Valencinia
,
Valencinina
and
Valencinura
, the proboscis pore is located far posterior to the cephalic tip. At least some species in
Valencinia
and
Valencinura
are similar to one another in external appearance. They supposedly differ in the presence (in
Valencinura
) or absence (in
Valencinia
) of (1) the proboscis inner longitudinal muscles and (2) the body-wall inner circular muscle layer in the foregut region (e.g. Bürger, 1895a; Bergendal, 1902; Senz, 1996).
Valencinina
and
Valencinura
are similar in having the proboscis anteroposteriorly differentiated into several regions. These two genera supposedly differ in the frontal organ, which is present in
Valencinina
but absent in
Valencinura
, and also in the outer longitudinal muscles in the posterior part of the proboscis, which are present in
Valencinura
but absent in
Valencinina
(Bergendal, 1902; Gibson, 1981b). Additional morphological data will be necessary to ascertain the generic affiliation of
Vu. jambio
.
Valencinura jambio
is almost certainly a different species from
Valencinura bahusiensis
View in CoL
and
Valencinura bergendali Senz, 1996
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. The uncorrected p -distance for COI between
Vu. jambio
and
Vu. bahusiensis
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(
GU392026
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; Strand & Sundberg, 2011) is 11.6%, a value considered high enough to indicate interspecific distance within any nemertean genus (cf. Sundberg et al., 2016b). The cephalic furrows seem to be lacking in
Vu. bahusiensis
View in CoL
, or at least are not as distinct as in
Vu. jambio
( Fig. 4C
View Figure 4
). In addition, the rhynchocoel and the proboscis are not evident on the dorsal surface of the body in the intestinal region, or at least are not as clearly evident as in
Vu. jambio
( Fig. 2E
View Figure 2
; cf. Strand et al., 2010: 122, unnumbered fig. with the caption ‘13 × naturlig storlek’).
Information on the external features of living animals and barcode sequences are lacking for
Vu. bergendali
View in CoL
. Compared to
Vu. bergendali
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, we ventured to establish
Vu. jambio
on the basis of smaller body diameter (~ 1 mm vs. 2.5 mm in
Vu. bergendali
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) and geographical separation (
Vu. jambio
in Japan;
Vu. bergendali
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in the Adriatic Sea). As the ending of the generic name suggests (-ura, from the Greek οὐρά, ‘tail’), the type species
Vu. bahusiensis
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possesses a caudal cirrus, while
Vu. bergendali
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lacks one. It remains to be determined whether
Vu. jambio
has a caudal cirrus.
Valencinura jambio
differs from all potential members of
Valencinia
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, although the latter genus requires taxonomic study with fresh material. As Corrêa (1956) has pointed out,
Valencinia
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was established without typespecies fixation for the four nominal species
Valencinia dubia Quatrefages, 1846
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;
Valencinia longirostris Quatrefages, 1846
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;
Valencinia ornata Quatrefages, 1846
; and
Valencinia splendida Quatrefages, 1846
.
Valencinia dubia
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(having eyes, and thus differing from
Vu. jambio
) was subsequently regarded as species inquirenda ( Bürger, 1904: 78);
Vi. ornata
was synonymized with
Tubulanus superbus ( Kölliker, 1845) ( Bürger, 1904: 13)
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; and
Vi. splendida
was synonymized with
Tubulanus polymorphus Renier, 1804 ( Bürger, 1895a: 517)
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. This left
Vi. longirostris
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as the only species that Friedrich (1936: 34) considered valid, which prompted Corrêa (1956: 204) to designate it as the type species.
Some other nominal species in
Valencinia
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are no longer regarded as congeneric. These include
Valencinia annulata Stimpson, 1855
[now
Tubulanus annulatus ( Montagu, 1804)
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];
Valencinia armandi McIntosh, 1875
(now
Carinoma armandi
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);
Valencinia elegans Stimpson, 1857
(now
Tubulanus annulatus
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);
Valencinia lineformis McIntosh, 1874
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(nomen dubium, having eyes);
Valencinia phalaerata Gay, 1849
(nomen dubium); and
Valencinia rubens Coe, 1895
(now
Zygeupolia rubens
View in CoL
) (see: Gibson, 1995: 533–535 for more details).
Hereweelevate Valencinialongirostris
var. rava Bürger, 1895a
to species rank as
Valencinia rava
;
rava
is an available species-group name in accordance with Article 45.6 of the Code ( ICZN, 1999). Originally established as
Valencinia longirostris var. rava
from Naples (along with a redescription of
Vi. longirostris
, also from Naples), this species was later regarded as subspecies
Joubinia longirostris rava ( Bürger, 1904: 86)
. Recognizing two subspecies in the same locality, however, is not in accord with the modern concept of subspecies ( Mayr, 1982; Monroe, 1982). As opposed to
Vi. longirostris
(posteriorly pink as in
Vu. jambio
),
Vi. rava
is posteriorly yellowish grey (and is thus different from
Vu. jambio
). The species
Valencinia blanca Bürger, 1895a
has a uniformly white body and, thus, also differs from
Vu. jambio
. For the three potentially valid species
Vi. blanca
,
Vi. longirostris
, and
Vi. rava
, no earlier researchers (e.g. Quatrefages, 1846; Hubrecht, 1879; Bürger, 1895a; Corrêa, 1956) described cephalic furrows, which are present in
Vu. jambio
. Indeed, Hubrecht (1879: 208) mentioned, as part of the generic diagnosis, that no cephalic furrows or fissures are present in
Valencinia
.
Morphologically,
Valencinia
shares with
Cephalomastax
an unusual proboscis musculature in which the proboscis nerve lies between the two (inner and outer) longitudinal muscle layers, an arrangement unique in the phylum ( Norenburg, 1993; Chernyshev, 2011a). To the extent that this morphological similarity indicates a close phylogenetic relationship,
Valencinia
is presumably more closely related to
Cephalomastax
than to
Valencinura
, which supports our placement of
Vu. jambio
in
Valencinura
rather than in
Valencinia
, despite their close relationship in our phylogenetic tree ( Fig. 1
View Figure 1
).
Valencinura jambio
differs from the two species in
Valencinina
in body colour:
Valencinina albula Gibson, 1981b
is cream white overall, whereas
Valencinina hubrechti Senz, 2001
is uniformly light brown.
Aside from species in
Valencinia
,
Valencinina
and
Valencinura
,
Vu. jambio
differs in the following features from all other known heteronemerteans lacking horizontal lateral cephalic slits: in habitat (marine) from
Apatronemertes
,
Planolineus
and
Siolineus
(freshwater); in phylogenetic position ( Fig. 1
View Figure 1
) from
Baseodiscus
,
Cephalomastax
,
Oxypolella
,
Riserius
,
Sonnenemertes
and
Zygeupolia
; in the nature of the cephalic furrows (paired and disjunct) from
Oxypolia beaumontiana
(continuous, encircling the head; Punnett, 1901); in body colour (anteriorly white; pink in the intestinal region) from
Paralineopsis taki
(blueish white anteriorly; foregut region pale yellow; intestinal region milky white; Iwata, 1993),
Paramicrura borborophila
(light beige-brown to pink-brown; Gibson & Sundberg, 1992),
Parapolia aurantiaca
(bright orange; Coe, 1895),
Parapolia grytvikensis
(pinkish brown; Wheeler, 1934),
Poliopsis lacazei
(dark pink; Joubin, 1890) and
Pseudobaseodiscus nonsulcatus
(light pink; Senz, 1993).
Valencinura jambio
further differs from
Poliopsis
in lacking the peculiar dorsal and ventral medial furrows on the head that are present in the latter ( Joubin, 1890).