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Periclimenaeus karantina sp. nov. and host colonial didemnid ascidian Leptoclinides sp.
Park & De Grave, 2021 Photos: J.H. Park. |
Two new species of the palaemonid genus Periclimenaeus are described and illustrated from Korea; additionally, a third species is recorded from Korea for the first time. Periclimenaeus karantina sp. nov. was obtained from ascidian hosts. The species has a denticulate dactylus on both second pereiopods, considered to be typical for ascidian associates. It can be separated from related species by the combination of the following characters: the carpocerite overreaching the anterior margin of the scaphocerite; the distolateral tooth of the scaphocerite exceeding the anterior margin of the lamella; the dactylus of the minor chela exceeding the fixed finger; and the ambulatory dactyli furnished with a minute proximal tooth. Periclimenaeus apomonosi sp. nov. was obtained from sponge hosts, and belongs to the P. robustus species-group, on account of the developed anterior median lobe on the tergite of the first abdominal somite. It can be distinguished from related species by the combination of the presence of a supraorbital tooth; the presence of a pointed process on the inferior orbital angle; the distolateral tooth of the scaphocerite terminating level with the anterior margin of the lamella; the antennal carpocerite reaching about 0.6 of the scaphocerite; the first and second chelae with non-serrated cutting edges; the ischium and merus of the second pereiopods harbouring tubercles on the ventral margin; and the ambulatory dactyli with a distal accessory tooth and the corpus furnished with denticles, ventrally. The sponge associated species, Periclimenaeus djboutensis, relatively widespread across the Indo-Pacific, is reported for the first time from Korea in Geomundo Island. Asides from a morphological description of all three species, molecular information of two genetic markers (16S + COI) is provided to aid in future phylogenetic reconstructions of the genus.
Key words: Caridea, Periclimenaeus spp. nov., Jejudo Island, Korea, Indo-West Pacific.
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Periclimenaeus karantina sp. nov. and host colonial didemnid ascidian Leptoclinides sp.
A, paratype, non-ovigerous female, pocl 3.5 mm (NIBRIV0000877272), colour pattern;
B, specimen (either OUMNH.ZC.2018-03-027 or 028) in the atrium of host ascidian from Museom Island;
C, habitat and host ascidian of a pair of P. karantina sp. nov. (NIBRIV0000877282 and 877283) in Seopseom Island.
Photos: J.H. Park. |
Periclimenaeus karantina sp. nov. Park and De
Grave
Etymology: From the Greek karantina (καραντίνα, quarantine), referring to the lifestyle of the new species within the host ascidian species (Fig. 9B). It also alludes to the quarantine of human society due to the coronavirus pandemic (COVID-19), during which time this paper was written. Used as a noun in apposition.
Host: The shrimp specimens were found
inside the common cloacal system of an colonial
didemnid ascidian Leptoclinides sp. (Ascidiacea:
Aplousobranchia: Didemnidae) (Fig. 9B, C).
Distribution: Presently only known from the type
locality in Jejudo Island, Korea (Fig. 1A, B).
Remarks: The species is considered to be
typical for ascidian associates due to the presence
of a denticulate dactylus on the minor second
pereiopod. Periclimenaeus karantina sp. nov. appears
morphologically close to seven species: P. colemani
Bruce, 2014, P. dactylodon Bruce, 2012a, P. devaneyi
Bruce, 2010, P. diplosomatis Bruce, 1980, P. kottae
Bruce, 2005a, P. myora Bruce, 1998, P. orbitocarinatus
Fransen, 2006; and possibly P. zarenkovi Ďuriš, 1990.
All these species share the following characters: 1) first
abdominal tergite without anterodorsal medial lobe; 2)
major and minor second chela with denticulate cutting
edges on dactylus; and 3) the dactyli of the ambulatory
pereiopods having a proximal ventral tooth, but no
distoventral accessory tooth.
...
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Periclimenaeus apomonosi sp. nov., paratype, male (pocl 2.6 mm) from Jejudo Island, Korea (NIBRIV0000862975).
A, dorsal view of specimen; B, specimen on dissected host sponge.
Photos: J.H. Park. |
Periclimenaeus apomonosi sp. nov. Park and
De Grave
Etymology : From the Greek apomonosi
(απομόνωση, isolation and seclusion), referring to the
lifestyle of the new species within the host sponge
species. It also alludes to the seclusion of human society
due to the coronavirus pandemic (COVID-19), during
which time this paper was written. Used as a noun in
apposition.
Host: The specimens were collected from an unidentified sponge (Fig. 15B).
Distribution: Presently only known from the type
locality in Jejudo Island, Korea (Fig. 1A, B).
Remarks: Periclimenaeus apomonosi sp. nov.
appears morphologically close to P. hebedactylus Bruce,
1970 and P. nufu Ďuriš, Horká & Hoc, 2009, sharing
with those species the presence of a supraorbital tooth
or ridge, the non-denticulate cutting edges of the dactyli
of the first and second pereiopods, and a distal accessory
tooth as well as the corpus with ventral denticles on the
ambulatory dactyli. Periclimenaeus tuamotae Bruce,
1969 and P. bidentatus Bruce, 1970 also resemble
the species in having a supraorbital tubercle and nontuberculate cutting edges. However, the presence of the
anterodorsal medial lobe of the first abdominal tergite
is not clear in the type (and only) descriptions (Bruce
1969 1970).
CONCLUSIONS:
Two new symbiotic species in the palaemonid
genus Periclimenaeus are described and illustrated
from Korea. Periclimenaeus karantina sp. nov. and P.
apomonosi sp. nov. were obtained from ascidian and
sponge hosts, respectively. In addition, the sponge
associated species, Periclimenaeus djiboutensis,
relatively widespread across the Indo-Pacific, is
reported for the first time from Korea. Along with a
morphological description of all three species, molecular
information from two genetic markers (16S + COI) is
provided to aid in future phylogenetic reconstructions of
the genus.
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