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A new species of Alvinocaris (Crustacea: Decapoda: Caridea: Alvinocarididae) from Costa Rican methane seeps


Abstract and Figures

A new caridean shrimp, Alvinocaris costaricensis, is described from methane seeps in the eastern Pacific off Costa Rica. The new species is the 16th described species of the genus, and by molecular analysis appears closest to Alvinocaris komaii from the Lau Basin, southwestern Pacific, but shares certain morphological characters with A. lusca from the Galapagos Rift and A. muricola from the West Florida Escarpment, as well as with A. kexueae from the Manus Basin in the Southwest Pacific.
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Accepted by J. Goy: 26 Jul. 2018; published: 25 Oct. 2018
ISSN 1175-5326 (print edition)
(online edition)
Copyright © 2018 Magnolia Press
Zootaxa 4504 (3): 418
A new species of Alvinocaris (Crustacea: Decapoda: Caridea: Alvinocarididae)
from Costa Rican methane seeps
Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007
Biology Department MS #33, Woods Hole Oceanographic Institution, Woods Hole, MA 02543
Scripps Institution of Oceanography, UCSD, La Jolla, CA 92093-0202
Corresponding author. E-mail:,
A new caridean shrimp, Alvinocaris costaricensis, is described from methane seeps in the eastern Pacific off Costa Rica.
The new species is the 16
described species of the genus, and by molecular analysis appears closest to Alvinocaris komaii
from the Lau Basin, southwestern Pacific, but shares certain morphological characters with A. lusca from the Galapagos
Rift and A. muricola from the West Florida Escarpment, as well as with A. kexueae from the Manus Basin in the Southwest
Key words: Caridea, Alvinocaris, methane seeps, Costa Rica
The caridean shrimp family Alvinocarididae is an unusual and interesting assemblage of species known only from
hydrothermal vents and cold seeps (Martin & Haney 2005; De Grave & Fransen 2011). Currently, the family
consists of nine genera and at least 32 species (Komai & Segonzac 2005; De Grave & Fransen 2011; Yahagi et al.
2014; Komai & Tsuchida 2015; Komai et al. 2016) (Table 1). More undescribed species are known to exist in
various collections around the world (e.g. see Komai & Segonzac 2005), and it is common to encounter
undescribed species as new vent and seep sites are explored. The most geographically widespread and speciose
genus, Alvinocaris, was reviewed by Komai & Segonzac (2005), at which time there were eight described species.
Additional species have been described in the twelve years since their review (listed in De Grave & Fransen 2011;
see also Yahagi et al. 2014; Vereschaka et al. 2015; Wang & Sha 2017; Table 2). Below, we describe a new species
of Alvinocaris from relatively shallow methane seeps off the coast of Costa Rica in the eastern Pacific Ocean.
TABLE 1. Shrimp genera of the family Alvinocarididae as of mid-2018.
Genus No. of described species
Alvinocaridinides Komai & Chan, 2010 2
Alvinocaris Williams & Chace, 1982 16 (including this paper)
Chorocaris Martin & Hessler, 1990* 5
Manuscaris Komai & Tshuchida, 2015 1
Mirocaris Vereschaka, 1997 2
Nautilocaris Komai & Segonzac, 2004 1
Opaepele Williams & Dobbs, 1995 3
Rimicaris Williams & Rona, 1986 2
Shinkaicaris Komai & Segonzac, 2005 1
*suggested to be synonymous with Rimicaris by Vereschaka et al. (2015)
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TABLE 2 . Species of the genus Alvinocaris described as of mid-2018, in alphabetical order, and the general geographic
region in which they were discovered.
A. alexander Ahyong, 2009 southern Kermadec Ridge, southwest Pacific
A. brevitelsonis Kikuchi & Hashimoto, 2000 Minami-Ensei Knoll, Okinawa Trough
A. chelys Komai & Chan, 2010 Gueishandao, Taiwan
A. costaricensis (this paper) Costa Rica, eastern Pacific
A. dissimilis Komai & Segonzac, 2005 Minami-Ensei Knoll, Okinawa Trough
A. komaii Zelnio & Hourdez, 2009 Lau Basin, southwest Pacific
A. kexueae Wang & Sha, 2017 Manus Basin, southwest Pacific
A. longirostris Kikuchi & Ohta, 1995 Okinawa Trough
A. lusca Williams & Chace, 1982 Galapagos Rift, Rose Garden
A. markensis Williams, 1988 Mid-Atlantic Ridge
A. methanophila Komai, Shank & Van Dover, 2005 Blake Ridge
A. muricola Williams, 1988 West Florida Escarpment
A. niwa Webber, 2004 Rumble V seamount, Pacific
A. solitaire Yah a g i et al., 2014 Central Indian Ridge, Indian Ocean
A. stactophila Williams, 1988 North Central Gulf of Mexico
A. williamsi Shank & Martin, 2003 Menez Gwen, North Atlantic
Materials and methods
Specimens were collected from off the Pacific coast of Costa Rica during two cruises (AT 15-44 and 15-59 in 2009
and 2010, respectively) to study methane seeps, with sampling carried out via the Deep Submergence Vehicle
(DSV) Alvin. Shrimp were collected via the DSV Alvin and photographed alive onboard ship with a Canon
PowerShot G9 camera mounted on a Leica S8APO stereomicroscope.
Specimens for morphological study were fixed in 10% seawater-formaldehyde and then preserved in 70%
ethanol after rinsing. Two specimens from the 2009 expedition, both from Mound 12 (details below), were sent to
the first author for initial examination and illustration. All illustrations in this paper are of the larger (female) of
those two specimens, which is designated the holotype. All illustrations were made with the aid of a Wild M5APO
dissecting microscope and drawing tube.
Abbreviations used in the description are CL (carapace length) and TL (total length), and OCL (orbital
carapace length), and for institutions NHMLAC (Natural History Museum of Los Angeles County), MZUCR
(Museo de Zoología, Universidad de Costa Rica), and SIO-BIC (Benthic Invertebrate Collection of the Scripps
Institution of Oceanography)
Specimens for DNA analysis were preserved directly in 95% ethanol, and genomic DNA was extracted from
legs of seven specimens of the new species using a Qiagen DNeasy Tissue kit. Cytochrome oxidase subunit 1
(COI) (partial, approximately 700 bp) was amplified using the primer pair LCO1490 (5’-GGT CAA CAA ATC
ATA AAG ATA TTG G- 3’) and HCO2198 (5’-ACT TCA GGG TGA CCA AAA AAT CA-3’) (Folmer et al.
1994). PCR mixtures contained 12.5 μL ProMega GoTaq Green DNA polymerase (3mM MgCl2, 400 μM each
dNTP, 1U Taq), between 50–100 ng DNA, and a reaction profile of 94ºC for 180s, 5 cycles of 94°C for 30s, 47°C
for 45s, and 72°C for 60s, 30 cycles of 94°C for 30s, 52°C for 45s, and 72°C for 60s and finally 72°C for 300s was
used. The COI sequences, lacking indels, were unambiguously aligned and blasted to other alvinocarids. TCS
(Clement et al. 2000) was used to construct a COI haplotype network for the seven specimens of A. costaricensis n.
The seven new sequences (GenBank Accession Numbers MH645099-MH645105) were also combined with a
COI dataset of available species of Alvinocarididae in GenBank, largely following those used in Vereshchaka et al.
(2015), including their choice of outgroup, the acanthephyrid shrimp Acanthephyra purpurea. COI sequences were
managed in Mesquite (Maddison & Maddison 2011) and aligned using Muscle (Edgar 2004). Pairwise
comparisons of COI sequences were conducted, and uncorrected distances were estimated in PAUP* 4.0b15
(Swofford 2002). The sequences were analyzed using maximum parsimony (MP) in PAUP* and maximum
likelihood (ML) with RaxML GUI and RaXML 8 (Silvestro & Michalak 2012; Stamatakis 2014). MP analyses
were run using heuristic searches (100 random stepwise addition replicates; bisection re-connection (TBR); zero-
Zootaxa 4504 (3) © 2018 Magnolia Press
length branches collapsed). Clade support was assessed using jackknifing (37% deletion) with 1000
pseudoreplicates with 100 random additions per iteration. The ML analysis was run with the data partitioned by
codon using the GTR+Γ model of substitution. Bootstrap support values were estimated by 1000 standard
bootstrap pseudo-replicates with the same model and partitions.
Taxo n o m y
Alvinocaris costaricensis, new species
Material examined. Holotype: SIO-BIC C12202, female (TL ~42 mm, CL 17.4 mm, OCL 10.4 mm, carapace
height 6.0 mm), Eastern Pacific Ocean, Costa Rica, Mound 12, Alvin dive 4503, 8.9307° N, 84.3072° W, 1005 m,
collector Greg Rouse, Feb/24/2009. Paratypes: SIO-BIC C13298, SIO-BIC C13299, same collecting data as for
holotype; MZUCR-3569-01, same collecting data as for holotype. NHMLAC LACM CR 2009.1 (ex SIO-BIC
C11140-1), ovigerous female (OCL 17.6 mm, TL 55 mm), same collecting data as for holotype. SIO-BIC C11157
and C12203, Eastern Pacific Ocean, Costa Rica, Mound 12, Alvin dive 4511, 8.9305° N, 84.3123° W, 1001 m,
collector Greg Rouse, March/5/2009; SIO-BIC C12203 1 badly damaged specimen (TL 13.2 mm, OCL 4.9 mm;
abdomen disarticulated, sex undetermined). Although damaged, this specimen was sequenced and is the same
species. SIO-BIC C11157 was sequenced and is the same species. SIO-BIC C11209, sex not determined, (TL 77.6
mm, CL 30.4 mm, OCL 17.1 mm; left side of carapace slightly inflated), Eastern Pacific Ocean, Costa Rica, Jaco
Scarp, Alvin dive 4590, 9.1176° N, 84.8395° W, 1800 m, collector Greg Rouse, Jan/11/2010. SIO-BIC C11183,
C11186, sex not determined, Eastern Pacific Ocean, Costa Rica, Mound 12, Alvin dives 4587 and 4588, 8.9307° N,
84.3072° W, 1005 m collector Greg Rouse, Jan/08 and 09/2010. These specimens were sequenced and are the same
Description. Body relatively robust for the genus, integument thin, smooth, shiny. Carapace (Figs. 1, 2) with
strong suborbital spine (Fig. 3A) and well developed pterygostomial spine exceeding length of orbital spine,
otherwise unarmed.
Rostrum (Figs. 1B, 2, 3A) well developed (tip broken in holotype but well developed in several paratypes),
extending forward and only slightly downward, with strong, sharp, anterior-curving teeth in row on dorsal border,
extending backward to about, or slightly posterior to, midlength of carapace, bearing 5–7 weakly developed teeth
along ventral border. Weak dorsal carina extending backward from rostrum along carapace to posterior border.
Larger specimens with rostrum strongly up-turned distally, bearing up to 10 dorsal and forward-directed teeth,
exceeding anteriorly beyond tip of scaphocerite and antennular peduncle.
Eighth thoracic sternite with well-developed and acute median tooth directed anteroventrally, produced beyond
coxa of pereopod 5 and visible in lateral view (Fig. 2).
Abdomen (Figs. 1A, 2) well developed, somite 6 with sharp posteriorly directed tooth on either side extending
posteriorly along telson (Fig. 3D); somite 5 with similar but shorter tooth and with acute posteroventral border;
somite 4 with acute posteroventral border.
Telson (Fig 2, 3D, E) long, exceeding length of uropods, lateral margins straight, slightly converging
posteriorly; each lateral margin bearing row of 7 movable spines; posterolateral corners each with single large
slightly medially-curved spine; posterior border bearing two pairs of small spines and 4 plumose setae; posterior
border slightly indented as shown. Uropodal rami each with border of plumose setae; exopod broader than
endopod, bearing diaresis and single lateral spine just posterior to acute tooth at border of diaresis, as shown (Fig.
Eyes fused mesially but distinct, each with small anterodorsal tubercle (Fig. 3A). Cornea with diffuse
pigmentation internally but no clear pigmented layer or region.
Antennular peduncle (Fig. 3C) extending beyond antennal scale, with relative lengths of articles 1 > 2 > 3;
article 1 with large lateral spine extending clearly beyond similar spine of article 2. Antennal scale (Fig. 3B) broad,
distally rounded, with acute anterolateral tooth extending almost to full length of scale.
Mouthparts (Fig. 4A–F) typical of genus (Komai & Segonzac 2005; Vereschaka et al. 2015).
Zootaxa 4504 (3) © 2018 Magnolia Press
FIGURE 1. A, Alvinocaris costaricensis new species, holotype female, SIO-BIC C12202, Eastern Pacific Ocean, Costa Rica,
live color photograph. B, same species, paratype female, C11186.
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FIGURE 2. Alvinocaris costaricensis new species, holotype female, SIO-BIC C12202, Eastern Pacific Ocean, Costa Rica,
lateral view, extremity of rostrum broken. Carapace length 10.4 mm (measured from back of the orbital sinus in a straight line
to posterior border of carapace).
First pereopod (cheliped) (Figs. 1A, 2, 3F–H) well developed, long, extending beyond bases of antennae when
outstretched; chela delicate for genus and strongly curved inward, bearing delicate pectinations along cutting
borders of both fingers; fingers of chela approximately 1.5 times length of propodal palm; carpus cup-shaped to
receive proximal end of propodus, and bearing brush of “cleaning setae” and large, acute tooth on inner margin.
Second pereopod (Figs. 2, 3I–K) shorter than first; chela delicate, approximately 4 times longer than wide,
both fingers bearing pectinate setal borders on cutting margin; fingers slightly exceeding length of palm; ischium
with single movable ventral spine.
Third through fifth pereopods (Fig. 5) similar, long and delicate; propodus longer than merus; merus longer
than carpus. Dactylus short, stout, with recurved sclerotized tip and ventral single row of 4 or 5 short, sclerotized
spines. Propodus with row of regularly spaced short spines along ventral border. Merus with 2 large, ventral
movable spines on P3, none on P4 and P5. Ischium with 2 ventral movable spines on P3 and P4, none on P5.
Female pleopod (Fig. 4G) with subequal rami bearing plumose setae; appendix interna short, simple, tapering
Coloration. Photographs of the holotype (Fig. 1A) and one paratype (Fig. 1B) show a largely translucent to
white shrimp with a pale or beige carapace, some orange or reddish coloration on the mouthparts, and delicate red
reticulations on the carapace and abdomen. The eye, although reflecting light in the photographs, appears to be
Etymology. The specific epithet reflects the location of the methane seeps off the Pacific coast of Costa Rica.
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FIGURE 3. Alvinocaris costaricensis new species, holotype female, SIO-BIC C12202, Eastern Pacific Ocean, Costa Rica. A,
eye and section of rostrum (above) and orbital spine (below); note minute dorsal tubercle on eye. B, antennal scale, right side,
dorsal view. C, antennular peduncle, right side, dorsal view. D, telson and left uropods, dorsal view. E, extremity
(approximately distal half) of telson. F, pereopod 1 (cheliped), right side, ventro-lateral view. G, pereopod 1, dorsal view. H,
higher magnification of pereopod 1, dorsal inner view. I, second pereopod, right side, lateral view. J, pereopod 2 propodus and
chela, outer view. K, pereopod 2 chela, inner view.
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FIGURE 4. Alvinocaris costaricensis new species, holotype female, SIO-BIC C12202, Eastern Pacific Ocean, Costa Rica. A,
left mandible, inner view. B, maxilla, inner view. C, maxilliped 1. D, maxilliped 2. E, maxilliped 3, lateral view. F, maxilliped 3
dactylus, inner view. G, first pleopod and appendix interna, right side.
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FIGURE 5. Alvinocaris costaricensis new species, holotype female, SIO-BIC C12202, Eastern Pacific Ocean, Costa Rica. A,
pereopod 3, left side, lateral view. B, same, close up of dactylus and distal half of propodus. C, pereopod 4, left side, lateral
view. D, close up of dactylus and distal half of propodus. E, pereopod 5, left side, lateral view. E, close up of dactylus and distal
half of propodus.
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FIGURE 6. Relationships among selected members of Alvinocarididae based on COI sequence data. A, Maximum likelihood
topology; numbers at nodes indicate bootstrap values. B, one of eight shortest trees from the maximum parsimony analysis of
COI matching jackknife consensus tree; numbers at nodes refer to parsimony jackknife score. C. Haplotype network generated
by TCS (Clement et al. 2002); holotype and 5 paratypes have identical COI sequences; paratype C11186 differs by one base.
Generic type species indicated (Type). Seep-dwelling species indicated (S).
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DNA sequence analysis. The seven COI sequences for A. costaricensis n. sp. were very similar, with six
(including that of the holotype) being identical, and one haplotype differing by only one base (Fig. 6C). These had
a closest pairwise distance (of ~12%) to Alvinocaris komaii (GenBank KP759373) from West Pacific hydrothermal
vents. Of the 505 bases in the COI dataset, 323 were constant, 158 were parsimony-informative, and 24 were
variable but parsimony-uninformative. The ML analysis (Fig. 6A) recovered Alvinocaris as paraphyletic, with A.
costaricensis n. sp. as the sister group to A. komaii. The Rimicaris+Opaepele+Shinkaicaris clade was nested within
Alvinocaris as sister to the A. costaricensis n. sp. + A. komaii clade, though this, and most other deeper nodes, had
low support. The four-known seep-dwelling alvinocaridids, A. methanophila, A. muricola, A. stactophila and A.
costaricensis n. sp., were scattered across the phylogeny and all had hydrothermal vent-dwelling taxa as sister
groups. The MP analysis (Fig. 6B) found eight shortest trees of length 547. These eight trees varied only slightly;
one of the most parsimonious trees with the same topology as the majority-rule consensus tree, and that of the of
majority-rule consensus tree for the parsimony jackknife analysis, is shown in Fig. 6B. The MP analysis recovered
a monophyletic Alvinocaris (with the exception of A. methanophila), though with poor support; as in the ML
results, A. costaricensis n. sp. was sister group to A. komaii.
Remarks. Morphological comparison. Alvinocaris costaricensis n. sp. is a large species for an alvinocaridid,
with some paratypes (e.g. SIO-BIC C11209 from the Jaco Scarp site) exceeding 75 mm TL and 64 mm OCL. The
species is easily identifiable as a member of Alvinocaris based on several characters uniquely shared by members
of that genus: the laterally compressed, well-developed and toothed rostrum, dentate posterior border on abdominal
somite 4, minute dorsal tubercle on the surface of the eye, strongly curved and minutely pectinate chelae, small
ischial spine on the second pereopod, parallel rows of small spines on the telson, and spination of pereopods 3 and
4, among other characters (Komai & Segonzac 2005, Vereschaka et al. 2015).
Among species of Alvinocaris, the new species is similar to A. muricola and also to A. kexueae in the size
(length) of the rostrum, the orientation of the dorsal rostral spination, and the relatively shallow dorsal angle of the
carapace. In all three species, the rostrum slopes more gradually, and bears larger teeth, than in most Alvinocaris
species (Komai & Segonzac 2005). However, there is much morphological variation in the rostrum of A. muricola.
Using the diagnostic key to species provided by Komai & Segonzac (2005), the new species keys to Alvinocaris
lusca, another eastern Pacific (Galapagos Rift and East Pacific Rise) species, based on the number of ventral rostral
teeth (fewer than 5) and the length/width ratio of the antennal scale. Additionally, A. lusca is one of the few species
of Alvinocaris that shares with the new species, a slightly indented posterior border of the telson (though not as
indented as in A. costaricensis). However, A. costaricensis differs from A. lusca in having a far slenderer major
cheliped, 2 (rather than 3) ventral meral spines on pereopod 3, and a much longer lateral spine on the basal article
of the antennal peduncle, which barely exceeds the length of the spine of the second article in A. lusca.
An interesting departure from typical species of Alvinocaris is the absence of ventral meral spines on pereopod
4. Komai and Segonzac (2005) considered the presence of these spines on pereopods 3 and 4 diagnostic for the
genus Alvinocaris. The new species has prominent meral spines on P3, but not on P4 or P5 indicating that the
generic diagnosis requires slight amendment. This difference does not warrant the erection of another genus, as all
other characters fit well within the known range of features described for the other 16 species of Alvinocaris. The
indented terminal border of the telson is also unique among species in the genus, with A. lusca being the closest
match in that character. However, variation in this character is known (Komai & Segonzac 2005), so we hesitate to
suggest this as a determining feature for field identification.
Molecular comparison. We place the new species in Alvinocaris, even though there is evidence from the ML
analysis (albeit weakly supported) (Fig. 6A) that the genus, as currently construed, could be paraphyletic (and
polyphyletic when A. methanophila is considered). However, further sequence data are required to properly resolve
this situation, and that question is beyond the scope of this study. Vereshchaka et al. (2015) also found a
paraphyletic Alvinocaris based on their analysis of COI and also of the available 16S rDNA sequences, but
maintained the genus as currently formulated, although they suggested that the sequence for A. methanophila on
GenBank (AY163260) was the result of incorrect identification or processing of the material. Vereshchaka et al.
(2015) did recover Alvinocaris (including A. methanophila) as a well-supported clade based on morphology, and A.
costaricensis n. sp. shared these features (notably the laterally compressed and carinate rostrum, eyes fused
medially with each bearing a small tubercle, and paired dorsal spines on the telson).
Co-occurring species. Another, and smaller, alvinocaridid species, differing both morphologically (with a
shorter rostrum lacking the extensive dorsal teeth seen in A. costaricensis) and molecularly, was also collected
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from the Mound 12 site (AD 4501, 1008 m depth). Further specimens of that species in the SIO collection represent
yet another undescribed species.
TABLE 3 . Localities and GenBank Accession numbers for alvinocarid shrimp used in this study.
*Formerly in Chorocaris, synonymized with Rimicaris by Vereshchaka et al. (2015).
The authors are grateful to Chief Scientist Lisa Levin, the captain and crew of the RV Atlantis, the crew of the DSV
Alvin, and the scientific participants of AT 15-44 and 15-59 for crucial assistance in specimen collection.
Collection and analysis of the Costa Rica specimens for this project was funded by US National Science
Foundation grants to L. Levin and GWR (OCE-0826254 and OCE-0939557). JWM and AW thank the Natural
History Museum of Los Angeles County for support.
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... (Rouse & Kupriyanova 2021), and Hesionidae Grube, 1850 (Rouse et al. 2018a), bivalves, e.g., Archivesica gigas (Dall, 1896) (Breusing et al. 2019), Pliocardia krylovata A.M. Martin & Goffredi, 2012(Martin & Goffredi 2012, and Bathymodiolus spp. (McCowin et al. 2020), and crustaceans, e.g., Alvinocaris costaricensis Martin, Wall, Shank, Cha, Seid & Rouse, 2018(Martin et al. 2018. ...
... (Rouse & Kupriyanova 2021), and Hesionidae Grube, 1850 (Rouse et al. 2018a), bivalves, e.g., Archivesica gigas (Dall, 1896) (Breusing et al. 2019), Pliocardia krylovata A.M. Martin & Goffredi, 2012(Martin & Goffredi 2012, and Bathymodiolus spp. (McCowin et al. 2020), and crustaceans, e.g., Alvinocaris costaricensis Martin, Wall, Shank, Cha, Seid & Rouse, 2018(Martin et al. 2018. ...
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The taxonomy of ribbon worms (Nemertea) is particularly challenging due to the sparsity of distinct morphological characters, causing a significant underestimation of the group's true diversity. The number of named deep-sea species is very limited and there is a vast number of undescribed deep-sea nemerteans still to be discovered. In this paper we figuratively 'cut the ribbon' and name seven new species of monostiliferous hoplonemerteans from seeps and seamounts along the Costa Rican margin, one from seeps along the Oregon margin, and one from vents of the Juan de Fuca Ridge, USA. The species Chernyshevia escarpiaphila gen. et sp. nov. and five species of the genus Alvinonemertes gen. nov. (Alvinonemertes dariae gen. et sp. nov., Alvinonemertes dagmarae gen. et sp. nov., Alvinonemertes christianeae gen. et sp. nov., Alvinonemertes claudiae gen. et sp. nov., Alvinonemertes tatjanae gen. et sp. nov.) represent Oerstediina, whereas the three species Tetrastemma sundbergi sp. nov., Tetrastemma polyakovae sp. nov., and Tetrastemma strandae sp. nov. represent Amphiporina. One species of tubulanid palaeonemerteans is described but not provided with a species name due to lacking sequence data for comparison. Additionally, we provide sequence data for one lineid heteronemertean, one reptant hoplonemertean, and two further eumonostiliferan hoplonemertean species. We use an integrative, turbotaxonomic approach combining DNA sequence data with concise morphological descriptions and fully digitized serial histological sections made available as cybertypes.
... The caridean family Alvinocarididae is endemic to chemosynthetic environments in deep water (252-4960 m depth), and is currently represented by 36 species in nine genera, Alvinocaridinides Komai & Chan, 2010, Alvinocaris Williams & Chace, 1982, Keldyshicaris Vereshchaka, Kulagin & Lunina, 2015, Manuscaris Komai & Tsuchida, 2015, Mirocaris Vereshchaka, 1997, Nautilocaris Komai & Segonzac, 2004, Opaepele Williams & Dobbs, 1995, Rimicaris Williams & Rona, 1986, and Shinkaicaris Komai & Segonzac, 2005(Komai & Tsuchida, 2015Vereshchaka et al., 2015;Komai et al., 2016;Wang & Sha, 2016Martin et al., 2018;Komai & Giguère, 2019). Vereshchaka et al. (2015) proposed to recognize three subfamilies to reflect the phylogenetic pattern inferred by them, Alvinocaridinae (Alvinocaris), Mirocaridinae (Mirocaris and Nautilocaris) and Rimicaridinae (Alvinocaridinides, Manuscaris, Opaepele, Rimicaris and Shinkaicaris). ...
... nov.). Alvinocaris costaricensis was recently described from a methane seep off Costa Rica, eastern Pacific, at depths of 1001-1800 m ( Martin et al., 2018). (Kikuchi & Ohta, 1995;Komai & Segonzac, 2005). ...
A new species of the caridean genus Alvinocaris , A. marimonte sp. nov., is described and illustrated on the basis of specimens collected from hydrothermal vents at three locations in Izu-Bonin and Mariana Arcs of the north-western Pacific Ocean, Myojin Knoll (1224 m depth), NW Eifuku (1574–1582 m depth) and NW Rota seamounts (525 m depth). It is the 17th species assigned to Alvinocaris , and differs from all other congeneric species in several morphological characteristics derived from the rostrum length and armature, the carapace armature, the shape of the posterior margin of the telson and the armature of the third and fourth pereopods. Results of molecular phylogenetic analyses based on partial sequences of the mitochondrial COI and nuclear ITS-I genes compared between specimens of A. marimonte sp. nov. and other known species of Alvinocaris supported our recognition of the new species, although available data are still limited. Alvinocaris marimonte sp. nov. is represented by two morphotypes, distinguished by the armature of the posterior margin of the telson (spines vs plumose setae), which were not detected as separate species by the molecular analysis. Our discovery of the intraspecific variation in the armature of the posterior margin of the telson led us to reassess diagnostic characters used to distinguish species within the genus Alvinocaris .
... Pyrolycus jaco sp. nov. is the first vertebrate species to be described from the Jacó Scar hydrothermal seep site, in addition to 21 invertebrate species newly described from this site (Aguado & Rouse 2011;Borda et al. 2013;Hatch et al. 2020;Lindgren et al. 2019;Martin et al. 2018;McCowin et al. 2020;Pearson & Rouse 2022;Rouse & Kupriyanova 2021;Rouse et al. 2018;Salazar-Vallejo 2020;Summers et al. 2014;Watson et al. 2016), illustrating the extent of novel biodiversity at the Costa Rica methane seeps. It is also the first representative of Pyrolycus in the eastern Pacific Ocean. ...
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A new species of the zoarcid genus Pyrolycus Machida & Hashimoto, 2002, Pyrolycus jaco sp. nov., is described from a hydrothermal seep environment named Jacó Scar in the eastern Pacific of Costa Rica. Four specimens were collected in 2018 between 1746–1795 m among tubeworm colonies around the seep. The new species is differentiated from its two western Pacific congeners by having a shorter head, snout, jaw, and pectoral fins. It is further diagnosed by having three postorbital pores and two occipital pores. Molecular sequences of the cytochrome c oxidase I gene are provided and are the first for the genus. The character states indicating miniaturization in this species are discussed. This is the first vertebrate species known from this composite reducing ecosystem and is the fourth hydrothermally-associated zoarcid from the eastern Pacific.
... Decapods are probably the most frequently studied crustaceans in the deep-sea habitats of Costa Rica, in part due to their larger sizes compared to other crustaceans and their commercial importance as fishery resources (e.g., shrimps, prawns, king crabs, lobsters) (Wehrtmann and Nielsen-Muñoz 2009;Vargas and Wehrtmann 2009). In addition to the taxonomy and diversity (e.g., Wehrtmann and Echeverría-Sáenz 2007;Vargas and Wehrtmann 2009;Macpherson and Wehrtmann 2010;Thurber et al. 2011;Martin et al. 2018;Azofeifa-Solano and Vargas-Castillo 2020), some research has also focussed on ecology Hernáez et al. 2011;Durkin 2018), reproductive biology (Echeverría-Sáenz and Wehrtmann 2011; Hernáez and Wehrtmann 2011a, b;Villalobos-Rojas and Wehrtmann 2011;Villalobos-Rojas and Wehrtmann 2014), fisheries (Wehrtmann and Nielsen-Muñoz 2009), and microbiome symbiosis (Goffredi et al. 2014). ...
Crustaceans are an important component of deep-sea biodiversity. A brief review of the history of expeditions and studies related to deep-sea crustaceans in Costa Rica is presented. We briefly discuss studies on crustaceans from the Costa Rican deep-sea environments, and we provided an updated list of species recorded for the Pacific and the Caribbean. A total of 147 species has been reported from Costa Rican deep sea; 8 species have been reported from the Caribbean, 138 from the Pacific, and 1 from both basins. Decapoda was the most diverse group with 87 species, followed by Copepoda (23 spp.) and Peracarida (19 spp.). The first deep-sea exploration in Costa Rica began with foreign efforts, with national projects and participation increasing in recent years. Most research dealing with crustaceans has been focused on reproductive biology, in collaboration with the deepwater shrimp fisheries. Future efforts to study the Costa Rican deep-sea will incorporate collaboration with foreign expeditions and private companies since the country does not have enough funding invested in its deep sea. Finally, we discuss the current threats to deep-sea crustaceans, as well as future perspectives for the study of this fascinating group in Costa Rica.
... The BA was conducted in MrBayes 3.2.6 (Huelsenbeck and Ronquist, 2001). Acanthephyra purpurea was used to root all trees following Martin et al. (2018) phylogeny. The best model was selected using Akaike Information Criterion (AIC) for ML and the Bayesian Information Criterion (BIC) for BA under jModelTest 2.1.10 ...
Specialist fauna populations from chemosynthetic ecosystems are connected through larval stages travelling in current highways in the vast deep sea. One shrimp family of such specialists, Alvinocarididae, is hitherto known to be endemic to vents and seeps with no reported occurrence in ephemeral organic-rich chemosynthetic habitats. Here we report the first occurrence of Alvinocaris muricola on experimentally deployed whale bones and wood parcels in the Brazil margin (21°to 26°S) at 1500 and 3300 m depth. We sequenced the COI, 16S and 28S markers for molecular identification of Southwest Atlantic (SWAtl) specimens and used COI sequences to inspect the molecular diversity and genetic distance between the SWAtl and the Atlantic Equatorial Belt (AEB) populations. SWAtl A. muricola exhibited lower nucleotide and haplotype diversities in comparison with populations along the AEB. The low genetic divergence detected here between the SWAtl and AEB populations is likely a result of lar-val connectivity through equatorial currents from the East Atlantic margin populations, whereas the SWAtl may be supplied through western boundary currents at bathypelagic depths. The occurrence of A. muricola in organic falls suggests the existence of other deep-sea chemosynthesis-based ecosystems in the SWAtl that could function as larval sources to organic islands and vice versa. Our study additionally supports the ecological stepping-stone role of organic falls between vent and seep ecosystems.
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One new species of alvinocaridid Alvinocaris kexueae sp. nov. is described from hydrothermal vents on the Manus Basin, Southwest Pacific. This is the fifteenth species in Alvinocaris Williams & Chace, 1982. The new species is easily recognized by the combination of the rostrum distinctively overreaching the distal end of the antennular peduncle, and the armature of its dorsal and ventral margins; the unarmed third abdominal segment, and by the posterior margin of the telson having one triangular tooth medially and 6 pairs unequal spines. It is morphologically most similar to A. brevitelsonis Kikuchi & Hashimoto, 2000 described from Minami-Ensei Knoll, Okinawa Trough, but can easily be distinguished from it by the proportionally longer rostrum, by the dorsal teeth of the rostrum, by the shape of the chela of the first pereiopod, and by the teeth on the fourth abdominal segment. The genetic divergence of COI gene analyzed clearly supports the new taxon.
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The paper addresses the phylogeny and classification of the hydrothermal vent shrimp family Alvinocarididae. Two morphological cladistic analyses were carried out, which use all 31 recognized species of Alvinocarididae as terminal taxa. As outgroups, two species were included, both representing major caridean clades: Acanthephyra purpurea (Acanthephyridae) and Alpheus echiurophilus (Alpheidae). For additional support of the clades we utilised available data on mitochondrial Cytochrome c Oxidase I gene (CO1) and 16S ribosomal markers. Both morphological and molecular methods resulted in similar tree topologies and nearly identical clades. We consider these clades as evolutionary units and thus erect two new subfamilies: Rimicaridinae (Alvinocaridinides, Manuscaris, Opaepele, Shinkaicaris, Rimicaris), Alvinocaridinae (Alvinocaris), whilst recognising Mirocaridinae (with genera Mirocaris and Nautilocaris) at subfamily level. One genus, Keldyshicaris could not be assigned to any subfamily and is thus left as incertae sedis. The monophyly of Alvinocardinae was supported by morphological data, but not supported by molecular data (two analyses); the monophyly of all subfamilies was supported both by morphological and molecular data. Chorocaris is herein synonymized with Rimicaris, whilst Opaepele vavilovi is herein transferred to a new genus Keldyshicaris. Morphological trends within Alvinocarididae are discussed and short biogeographical remarks are given. We provide emended diagnoses for all subfamilies and genera along with keys to all recognized species.
Seventy-two specimens representing two new species of Alvinocaris of the family Alvinocarididae, A. brevitelsonis and A. leurokolos, were found in samples collected from thermally influenced fields at the Minami-Ensei Knoll (28°23.35'N, 127°38.38'E, 705m depth). The shrimps appeared to be the co-dominant macroinvertebrates in the small hollows of chimneys and among the mussel beds, bathing directly in vent fluids in the high temperature hydrothermal field. A key to the seven known species of Alvinocaris is given.
Five species of caridean shrimp, including four Alvinocarididae Christoffersen, 1986 and one thorid species of the genus Lebbeus White, 1847, are reported from the recently discovered hydrothermal vent field off Futuna Island in the Southwest Pacific (depths 1418–1478 m): Alvinocaridinides semidentatus n. sp., Alvinocaris komaii Zelnio & Hourdez, 2009, Nautilocaris saintlaurentae Komai & Segonzac, 2004, Rimicaris variabilis (Komai & Tsuchida, 2015), and Lebbeus wera Ahyong, 2009. The new species, provisionally assigned to Alvinocaridinides Komai & Chan, 2010, is readily distinguished from the type species of the genus, A. formosa Komai & Chan, 2010, by the characteristic armature of the rostrum and of the propodi of the third and fourth pereopods and the possession of ischial spines on the third and fourth pereopods. Identification of R. variabilis has been confirmed by morphology and sequence comparison of mitochondrial COI gene. The geographical range of L. wera is extended to the north from the Brothers Caldera in the Kermadec Ridge.
Alvinocaris niwa n. sp. is described from hydrothermal vents at the Brothers Caldera and Rumble V Seamount on the southern Kermadec Ridge, midway between the Kermadec Islands and Bay of Plenty, New Zealand. Four hundred specimens of Alvinocaris longirostris Kikuchi & Ohta, 1995, described from Japan, are recorded at the Brothers. The presence of a possible third Alvinocaris at Rumble V and one or two species of Chorocaris at Brothers are also reported. Eighty-eight specimens of A. niwa and 41 of A. longirostris were measured and examined to assess morphological variation. Morphological characters used to distinguish alvinocaridids are shown to be highly variable. Pairwise correlations with carapace length indicate that numbers of teeth, spines and setae are generally not related to shrimp size. Descriptions based on small numbers of specimens are thus questionable. The new species is characterised by: short rostrum; paired sternal spines on abdominal somites I - III; long stylocerite and robust distolateral spine on the antennular proximal segment, with a subterminal spine; two ventral spines on antennal basal segment; row of spines on distal segment of maxilliped III; and two rows of spines on flexor surface of P3 - P5 dactyls. It is the shallowest alvinocaridid yet discovered and also inhabits the greatest depth range, at over 700 m.
Two species of the alvinocaridid shrimp genus Alvinocaris, A. methanophila n. sp. and A. muricola Williams, are reported from a cold seep site on the Blake Ridge Diapir, northwestern Atlantic, at a depth of 2155 m. Alvinocaris methanophila is described and illustrated on the basis of 33 adult specimens. It is most similar to the sympatrically found A. muricola Williams, but differs in the comparatively stout second segment of the antennular peduncle and smaller size at maturity in females. Available data suggest that A. muricola is rare at this site. Brief notes on habitat and distribution of the two species are provided.
Three new species of the caridean family Alvinocarididae are described from hydrothermal vents in the Southwest Pacific, namely, Chorocaris parva sp. nov. (Manus Basin, 1305–1684 m), Chorocaris variabilis sp. nov. (Manus and North Fiji basins and Vanuatu, 1305–2480 m) and Manuscaris acuminatus gen. et sp. nov. (Manus Basin, 1310 m). Morphological affinities of these three species are discussed. Molecular genetic analysis using partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene supports the recognition of the two new species assigned to Chorocaris Martin and Hessler, 1990. The generic diagnosis of Chorocaris is slightly emended to accommodate the two new species. Opaepele susannae Komai, Gierre and Segonzac, 2007 is transferred to Chorocaris. Alvinocaris komai Zelnio and Hourdez, 2009, originally described from the Lau Basin, is newly recorded from the North Fiji Basin and Vanuatu (Nifonea vent field), at depths of 1740–2750 m.