Research Article |
Corresponding author: Supiyanit Maiphae ( supiyanit.m@ku.ac.th ) Academic editor: Michael Ohl
© 2015 Thanida Saetang, Supiyanit Maiphae.
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:
Saetang T, Maiphae S (2015) A new species of Parategastes Sars, 1904 from the Thale Noi Lake, southern Thailand (Copepoda, Harpacticoida, Tegastidae). Zoosystematics and Evolution 91(2): 167-176. https://doi.org/10.3897/zse.91.5283
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Parategastes pholpunthini sp. n. is described and illustrated based on material collected in the Thale Noi Lake, Phatthalung province, southern Thailand. This species can be distinguished from its congeners by the number segments of female antennule, the lengths of rami and basis of P1, the shape of middle inner seta of P4 exp-3, shape of P5, and relative lengths of spine at apically of baseoendopod of P5. The differences among Parategastes species are pointed out and they are compared with the new species. An identification key to species of the genus Parategastes are proposed.
Crustacea , Meiofauna, Taxonomy, Parategastes pholpunthini
The family Tegastidae Sars, 1904 is characterised as being laterally compressed, amphipod-like, strongly chitinous and well sculptured (
Samples were collected from Thale Noi Lake, Phatthalung province, southern Thailand, using a 60 µm mesh sized plankton net, every two months from February 2013 to February 2014. Samples were immediately preserved in 70% ethanol. Then specimens were sorted using an Olympus SZ-40 stereo microscope and each specimen was dissected and mounted on a slide in glycerine, and then sealed using nail varnish. The morphological characters were examined using an Olympus CH-2 compound microscope, and drawings were made of both complete and dissected specimens using a camera lucida connected to the Olympus CH-2 compound microscope. Descriptive terminology proposed by
P. sphaericus (Claus, 1863)
P. chalmersi (Thompson & Scott, 1903)
P. caprinus Wellershaus, 1970
P. coetzeei Kunz, 1980
P. conexus Humes, 1984
P. herteli Jakobi, 1953
P. pholpunthini sp. n.
P. haphe Leigh-Sharpe, 1936 (incertae sedis)
Parategastes sphaericus (Claus, 1863).
Parategastes Sars, 1904. antennules with 6-7 segments in female and 8 segments in males; exopod of antenna with one segment and with two or three setae; anterior maxilliped with the 2 proximal lateral lobes replaced by simple setae, outermost lobe less broad and provided with only two setae at the tip, terminal joint produced at the tip to a long digitiform process. P2 and P3 with 2-segmented endopod and 3-segmented exopod; and P4 with 3-segmented endopod and exopod, whilst enp-1 was not swollen. P5 in female, baseoendopod very large, with inner expansion to broad and vaulted, exopod somewhat dilated towards the end, with a single short apical seta.
Holotype: adult female, dissected and mounted on 4 slides, (PSUZC-PK2001-01-PSUZC-PK2001-04); Paratype 1: undissected female, mounted on 1 slide, (PSUZC-PK2001-05); Paratype 2: undissected adult male, mounted on 1 slide, (PSUZC-PK2001-06); Paratype 3: adult female, dissected on 4 slides, (PSUZC-PK2001-07-PSUZC-PK2001-10); Paratype 4: adult male, dissected on 4 slides, (PSUZC-PK2001-11-PSUZC-PK2001-14). All specimens were collected from the type locality on 23 October 2013.
8 females and 8 males from the type locality are stored in 70% ethanol.
Klong Ban Klang canal, Thale Noi Lake, Phatthalung province, southern Thailand (07°46’30.47”N, 100°9’31.68”E). The canal is connected to Songkhla Lake. Water temperature ranged between 28.3 to 28.5 °C, pH of 5.71–6.07, salinity 1.1 ppt, depths between 0.8 m to 1.35 m, transparency of 0.2–1.35 m, and dissolved oxygen levels of 3.06–4.24 mgO2/L. This area was covered with aquatic plants, such as Neptunia oleracea Lour., Eichhornia crassipes (C. Mart.) Solms, and Nympheas sp.
Body laterally compressed with sensilla, surface of whole body pitted (Fig.
Egg sac (Fig.
Rostrum (Fig.
Antennule (Fig.
Antenna (Fig.
Mandible (Fig.
Maxillule (Fig.
Maxilla (Fig.
Maxilliped (Fig.
P1 (Fig.
P2 and P3 (Figs
P4 (Fig.
Armature formula of P1-P4 as in Table
Swimming legs | Coxa | Basis | Endopod | Exopod |
---|---|---|---|---|
P1 | 0-0 | 1-1 | 1, II, II1 | 2, 1II, 0 |
P2 | 0-0 | 1-0 | 0-1; 0-2; I, II, 2 | [I-0, I-1]; I, II1, 2 |
P3 | 0-0 | 1-0 | 0-1; 0-2; I, II, 3 | [I-0, I-1]; I, II1, 3 |
P4 | 0-0 | 1-0 | 0-1; 0-1; I, II, 0 | I-0; I-1; I, II1, 2 |
P5 (Fig.
Body laterally compressed (Fig.
Antennule (Fig.
Rostrum, antenna, mandible, maxillule, maxilla, maxilliped, P1-P4 (not shown) as in female.
P5 (Fig.
This species named after Dr. Pornsilp Pholpunthin, who has studied the freshwater copepods in Southern Thailand since last twenty years.
Four Parategastes species have been recorded in the Oriental region (
Parategastes pholpunthini sp. n. is clearly distinguished from other Parategastes species in the following characters: (1) number of antennule segments of female, 7-segmented in most species of Parategastes, except P. coetzeei and P. pholpunthini sp. n. with 6-segmented; (2) P1, length of rami and basis in this genus can be separated into three groups: the first group, rami shorter than basis, comprises of P. chalmersi and P. conexus, the second group, rami approximately as long as basis, comprises of P. herteli and P. sphaericus and the third group, rami longer than basis, comprises of P. caprinus, P. coetzeei and P. pholpunthini sp. n. (Table
From the comparisons, it was found that Parategastes pholpunthini sp. n. resembles P. coetzeei, but differs from the latter in the following characters: (1) P1, proximal inner seta of endopod 1.08 times as long as the endopod in P. pholpunthini sp. n. (Fig.
Comparison of characters of female of Parategastes species (modified from
Species/characters | A1 | Exp of A2 (setae) | P1 | P2-P4 | P4 exp-3 | P5 | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
rami/basis | setae | inner middle spine of enp | inner setae | enp-3 | middle inner seta | outer setae | baseoendopod | ||||||
enp | exp | enp-1 | enp-2 | shape | inner/outer spine (seta) | ||||||||
P. sphaericus | 7 | 2 | m | 6 | 5 | slender | 1:1:1 | 2:2:1 | 5:6:3 | thickened, with serrated | 2 | sub-oval | A |
P. chalmersi | 7 | - | s | 5 | 4 | slender | 1:1:1 | 2:2:2 | 5:6:6 | thickened, without serrated | 3:wd: B | sub-oval | A |
P. caprinus | 7 | 3 | l | 6 | 5 | slender | 1:1:1 | 2:2:2 | 5:6:3 | thickened, with serrated | 3:rud | sub-oval | A |
P. conexus | 7 | 3 | s | 6 | 5 | slender | 1:1:1 | 2:2:2 | 5:6:5 | enlarged, 3 teeth at the distal end | 3:wd: A | sub-triangular | A |
P. herteli | 7 | 3 | m | 6 | 5 | slender | 1:1:1 | 2:2:2 | 5:6:3 | enlarged | 2 | sub-oval | A |
P. coetzeei | 6 | 3 | l | 6 | 5 | thickened | 1:1:0 | 2:2:2 | 5:7:3 | slender | 2 | sub-oval | B* |
P. pholpunthini sp. n. | 6 | 3 | l | 6 | 5 | thickened | 1:1:1 | 2:2:1 | 5:6:3 | enlarged, bending, pinnae at the distal third and distal end | 2 | sub-oval | B** |
At present, the taxonomic status of members of the genus Parategastes is still unclear. Original descriptions and illustrations of type specimens of some species are poor. It seems that this genus is in need molecular data of each species.
1 | Endopod and exopod of P1 with 5 and 4 setae | P. chalmersi (Thompson & Scott, 1903) |
– | Endopod and exopod of P1 with 6 and 5 setae | 2 |
2 | Exopod of antenna with two setae | P. sphaericus (Claus, 1863) |
– | Exopod of antenna with three setae | 3 |
3 | Rami of P1 shorter than basis | P. conexus Humes, 1984 |
– | Rami of P1 equal or longer than basis | 4 |
4 | A1 with 7 segmented, middle inner spine of endopod of P1 is slender | 5 |
– | A1 with 6 segmented, middle inner spine of endopod of P1 is thickened | 6 |
5 | P1, endopod and exopod approximately as long as basis, proximal seta of inner edge of endopod longer than segment. Exp-3 of P4 with 2 outer seta | P. herteli Jakobi, 1953 |
– | P1, endopod and exopod longer than basis, proximal seta of inner edge of endopod shorter than segment. Exp-3 of P4 with 3 outer setae | P. caprinus Wellershaus, 1970 |
6 | Length of inner apical seta of baseoendopod of P5 as long as outer apical seta. Enp-1 of P4 without inner seta | P. coetzeei Kunz, 1980 |
– | Length of inner apical seta of baseoendopod of P5 is twice of outer apical seta. Enp-1 of P4 with 1 inner seta | P. pholpunthini sp. n. |
This research was financial supported by National Research University (NRU) and Graduate School, Prince of Songkla University. The study was carried out under the Center of Excellence for Biodiversity of Peninsular Thailand (CBIPT), Department of Biology, Faculty of Science, Prince of Songkla University, and Department of Zoology, Faculty of Science, Kasetsart University.