Research Article |
Corresponding author: Chang-Keun Kang ( smire425@gist.ac.kr ) Academic editor: Yasen Mutafchiev
© 2018 Jin Hee Wi, Chang-Keun Kang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wi JH, Kang C-K (2018) A new genus and species of Sphyrapodidae (Crustacea, Peracarida, Tanaidacea) from the southern coast of the South Korea. ZooKeys 735: 45-64. https://doi.org/10.3897/zookeys.735.14671
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Wandogarida canalicula gen. n et sp. n. (Tanaidacea, Sphyrapodidae) is described from the southern coast of Korea (NW Pacific). The genus is included in the subfamily SphyrapodinaeGuţu, 1980 by having a mandible lacking a palp. It has a close affinity with the genus Poligarida Bamber & Marshall, 2013 in the third pereonite having lateral pointed apophyses, the antennule of males with fringes of aesthetascs on articles 1 and 2 of the outer flagellum and the antenna with an elongate article 2. However, it is distinguished from Poligarida by having a maxillular palp. Wandogarida gen. n. can be differentiated from other genera within the subfamily Sphyrapodinae by the unique shape characterised by the male’s antennule article 1 with its rough denticles and a deep groove, pleonites each with a ventral hyposphenium, the maxillule with uniarticulate palp and the presence of prominent sexual dimorphism in the mouthparts. An identification key to the five genera of the subfamily Sphyrapodinae is presented.
Tanaidacea , Apseudomorpha , Sphyrapodinae , Wandogarida , sexual dimorphism
The suborder Apseudomorpha Sieg, 1980 includes about 460 species and is widely distributed in various shallow marine benthic habitats, being quite abundant in coral reefs, estuaries and mangrove swamps, from the tropics to temperate regions (
More than 300 sphyrapodid specimens were collected during a recent survey of the shallow mud sandy seabed from the southern coast of South Korea. Their examination revealed the presence of a new species in a new genus belonging to the subfamily Sphyrapodinae.
The materials were obtained from the sandy bottom off Wando Island on the southern coast of South Korea: (34°31.1'N; 128°33.2'E at a depth of 41 m) in October 2015 using an epi-sledge net. The specimens were extracted by filtering the substrates through a 350 μm sieve and the residue from each sieve was preserved in a 99% alcohol solution. Later, the animals were identified and counted in the laboratory. The specimens were dissected under a dissection microscope (Nikon SMZ745T) in CMC-10 aqueous mounting medium (Masters, Wood Dale, IL, USA), mounted on slides and then sealed with high-quality nail varnish. Drawings were generated using a differential interference contrast microscope (Nikon Y-IM) that was equipped with a drawing tube. The total body length was measured from the tip of the rostrum to the pleotelson apex in the dorsal view. Scale bars are given in mm. The morphological terminology follows
Rostrum narrow and prominently extended. Carapace wider than long. Pereonite 3 with lateral apophyses. Pleonites each with a ventral spur and pointed epimera. Pleotelson with slight distal extension. Antennule inner flagellum biarticulate; peduncle article 1 in males with a vertical row of rough denticles and groove. Antenna 8-articulate, without squama. Mandible without palp; molar with distal setulose setae and spinose cutting edge. Maxillule with uniarticulate palp. Pereopods 2–4 propodus with ventral seta. Uropod exopod 3-articulate.
The name refers to Wando, a port city near the type locality and garida from the Greek γαίδα, meaning “shrimp” (feminine).
Wandogarida canalicula sp. n.
Wandogarida gen. n. is classified in the subfamily Sphyrapodinae following
The subfamily is now composed of five genera: Ansphyrapus Guţu, 2001, Poligarida Bamber & Marshall, 2013, Sphyrapoides Guţu & Iliffe, 1998 and Sphyrapus Sars, 1882, including the new genus Wandogarida.
Wandogarida resembles Poligarida in the absence of an antennal squama, antennule with a biarticulate inner flagellum, pereonite 3 with anterolateral pointed apophyses and outer flagellum of the male antennule with fringes of aesthetascs. However, Wandogarida can be differentiated from Poligarida by the following: in both sexes, the number of antenna articles is different (8 vs. 7); the maxillule has a uniarticulate palp (vs. absence); the carpus and propodus of pereopods 2–3 and propodus of the pereopod 4 have ventral spiniform setae (vs. absence); in females, the mandible molar has several setulose distal setae and sharp, spinose distal margin (vs. with distal setae and simple distal edge); in males, sexual dimorphism exists in the antennule article 1 with a vertical row of rough denticles and concave distolateral margin, in reduced and simplified mandibles, maxillule, maxilla and maxilliped endite, in the larger and more robust cheliped and in the shape of ventral margin of the pereopod 1 dactylus, while it exists only in the antennule, cheliped and pereopod 1in Poligarida.
1 | Antennule inner flagellum with 0–1 articles | Sphyrapus |
– | Antennule inner flagellum with 1–2 articles | 2 |
2 | Antenna with squama | Sphyrapoides |
– | Antenna without squama | 3 |
3 | Maxillule with palp | 4 |
– | Maxillule without palp | Wandogarida gen. n. |
4 | Pereopod 6 with many long setae along basis, merus and carpus | Ansphyrapus |
– | Pereopod 6 without many long setae along basis, merus and carpus | Poligarida |
Holotype: (MABIK CR00240685) female dissected and mounted on five slides. Allotype: (MABIK CR00240686) male dissected and mounted on five slides; from the same locality as the holotype. Paratypes: Four females partly dissected on one slide (MABIK CR00240687) and in 3 vials (MABIKCR00235359–MABIKCR00235361); from the same locality as the holotype. Four males partly dissected on one slide (MABIK CR00240688) and in 2 vials (MABIKCR00235362, MABIKCR00235363); from the same locality as for holotype.
Wando, South Korea (North West Pacific), 34°31.02'N, 128°33.11'E, mud-sandy bottom at a depth of 41 m.
The specific name is derived from Latin canalicula, meaning a groove and refers to the conspicuous groove formed on the distal margin of the male antennule.
Female (with oostegites). Body (Fig.
Wandogarida canalicula gen. n., sp. n., holotype, female: A habitus, dorsal view, upper arrow indicating apophysis of pereonite 3 and lower arrow indicating epimera of pleonite 5 B pleon, lateral view, arrow indicating hyposphenium of pleonite 1 C pleotelson, lateral view D antennule E antenna. Scale bars are given in mm.
Pereon (Fig.
Pleon (Fig.
Antennule (Fig.
Antenna (Fig.
Labrum (Fig.
Wandogarida canalicula gen. n., sp. n., holotype, female: A labrum B left mandible, arrow indicating eight distal setulose setae on molar C right mandible D labium, arrow indicating distal spine of palp E maxillule, upper arrow indicating two subdistal setulose spiniform setae on outer endite and lower arrow indicating uniarticulate palp F uropod. Scale bars are given in mm.
Left mandible (Fig.
Labium (Fig.
Maxillule (Fig.
Maxilla (Fig.
Wandogarida canalicula gen. n., sp. n., holotype, female: A maxilla B maxilliped, arrow indicating three curved spines on basis C maxilliped endite D epignath, arrow indicating long wrinkled seta on distal margin E cheliped, arrow indicating dorsomedial protrusion on basis F cheliped exopodite G fixed finger of cheliped, arrow indicating setulose seta near cutting edge. Scale bars are given in mm.
Maxilliped (Fig.
Cheliped (Fig.
Pereopod 1 (Fig.
Pereopod 2 (Fig.
Pereopod 3 (Fig.
Pereopod 4 (Fig.
Pereopod 5 (Fig.
Pereopod 6 (Fig.
Pleopods 1–5 (Fig.
Uropod (Fig.
Male. Body (Fig.
Wandogarida canalicula gen. n., sp. n., allotype, male: A habitus, dorsal view B pleonites and pleotelson, lateral view, arrows indicating upper and lower margins of hyposphenium of pleonite 1 C epimera of pleonite, arrow indicating simple seta D distal extension of pleotelson, ventral view E antennule, arrow indicating projection having row of rough denticles and inverted triangle indicating deep groove between projection and smooth margin F antenna G uropod. Scale bars are given in mm.
Pereon (Fig.
Pleon (Fig.
Antennule (Fig.
Antenna (Fig.
Labrum and labium almost equal to those of female.
Left mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
Cheliped (Fig.
Pereopod 1 (Fig.
Wandogarida canalicula gen. n., sp. n., allotype, male: A pereopod 1 B pereopod 2 C pereopod 3 D–E paratype, male D pereopod 4 E pereopod 4, distal margin of propodus, dactylus and unguis F–H allotype, male F pereopod 5 G pereopod 5, dactylus and unguis H pereopod 6. Scale bars are given in mm.
Pereopod 2 (Fig.
Pereopod 3 (Fig.
Pereopod 4 (Fig.
Pereopod 5 (Fig.
Pereopod 6 (Fig.
Pleopod (Fig.
Uropod (Fig.
To check the morphological variation with size, ten specimens (1.64–2.73 mm) were partly dissected and the cheliped, the pereopod 1 and a ventral hyposphenium of pleonite were examined for different sizes and some variations were found: 1) in the cheliped, the dactylus and fixed finger of the males were modified in size: in the cheliped of the large sized males (over 2 mm), the cutting edge of the dactylus is extended and strongly curved and the processes on the proximal margin are prominently developed; 2) the number and size of setae on the pereopod 1 propodus increased with size; 3) a ventral hyposphenium of the male pleonite is modified from a rounded shape to a subrectangular shape, with body length reaching over 2 mm.
Sexual dimorphism within the genera Ansphyrapus and Sphyrapoides affects only their chelipeds, while in Sphyrapus and Poligarida, it affects their antennule, cheliped and pereopod 1. However, Wandogarida canalicula gen. n., sp. n. exhibits a greater level of sexual dimorphism: 1) the female body is wider than males, 2) in the antennule, the distal surface of the article 1 is round and naked in females, while that of the male has a vertical row of rough denticles and a deep groove; the outer flagellum of males is 5-articulate and the first and second articles have fringes of aesthetascs, but that of the female is 3-articulate and bears only one aesthetasc each on the first and second articles, 3) in the mandible, the incisor and lacinia mobilis of the left mandible of the female have distal denticles, but those of the male are distally pointed and naked and the setae of the setal row are shorter and more slender than those of the female. The setal row of the right mandible also differs (a row of five denticles and a small pointed seta in the male vs. a robust tripartite seta and three setulose setae in the female), 4) in the maxillule, the distal setae on the outer and inner endites of males are shorter than those of females, 5) the setae on the maxilla of males are diminished in size, as compared to those of the female, 6) the maxilliped endite of the male lacks inner setae and the distal margin has six naked and reduced spiniform setae, while that of the female has four plumose setae along the inner margin and eight distal spiniform setae, 7) in the cheliped, the basis, fixed finger and dactylus show dimorphism: the basis of the male is more robust than in the female, the cutting edge of the fixed finger has slender and pointed denticles and processes, but that of the female has distally broad denticles; the dactylus of the male has several denticles and processes along the cutting edge, but that of the female is naked and 8) the pereopod 1 of the male is longer than that of the female and the dactylus also shows a different shape in the both sexes: the ventral margin has small denticles in the male but spines in the female.
These results in the sexual dimorphism and morphological variation with body size shown in W. canalicula can be used as an important tool to divide easily and precisely males and females of the sphyrapodid species and upgrade our understanding how their life cycle or morphological function adapts to diverse environments.
This study was part of the project entitled ‘Long-term change of structure and function in marine ecosystems of Korea’, funded by the Ministry of Oceans and Fisheries, Korea.