Research Article |
Corresponding author: Hazel Baytaşoğlu ( gokbuluthazel@gmail.com ) Academic editor: Rachael Peart
© 2023 Hazel Baytaşoğlu.
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:
Baytaşoğlu H (2023) A new freshwater amphipod (Arthropoda, Malacostraca, Amphipoda, Gammaridae), Echinogammarus ozbeki sp. nov. from the Tomara Waterfall, Turkey. ZooKeys 1173: 231-242. https://doi.org/10.3897/zookeys.1173.102946
|
A new species of freshwater amphipod, Echinogammarus ozbeki sp. nov., collected from Tomara Waterfall, Gümüşhane province, northeastern Anatolia, is described and illustrated. The new species belongs to the genus Echinogammarus and exhibits characteristic uropod 3 features of that genus. Some of the distinctive features of the Echinogammarus ozbeki sp. nov. species are a small body length, urosome segments without dorsal elevations, distal end of the peduncle segments of antenna 1 with setae longer than the diameter of the segment, presence of strong spines accompanying setae on both inner and outer margin of exopod, and uropod 3 parviramous.
Freshwater, morphology, new taxa, taxonomy
A waterfall is a landform that occurs when water falls down a long or short distance due to the slope of the riverbed. Waterfalls, which are natural wonders, not only possess tourist potential but also serve as subjects for scientific studies in terms of geology, geography, phytology, and zoology. While Türkiye is one of the countries with high potential in terms of natural beauty and biodiversity, there are still deficiencies regarding the biodiversity of water resources (
Species of the order Amphipoda belonging to marine, freshwater, estuarine, cave, and underground water sources are frequently encountered. Amphipoda are represented by 16 families and 31 genera, and Gammaridae is the most commonly encountered family with 64 species in water resources in Türkiye (
This study examines the individuals of Echinogammarus collected from Tomara Waterfall, Gümüşhane province, in terms of morphological features. Detailed descriptions and drawings are given of the extremities of the holotype male of a newly identified species, and the morphology of this new species is compared with its relatives.
Located within the borders of Şiran district of Gümüşhane province, Tomara Waterfall has an area of 70,000 m2 and flows from an altitude of approximately 1380 m. Its source is underground waters which pass through a deep, narrow valley and flow into Kelkit stream. The habitat is rocky, and vegetation is quite abundant. (Fig.
The distance between Gümüşhane and Şiran is 101 km, and the distance between Şiran and Tomara Waterfall is 21 km. There is an area available for visitors along the river that continues from the waterfall. To reach the Tomara Waterfall on foot from the lower basin of the river, the distance I approximately 1 km. The waters of this waterfall emerge from a karstic source, and its geological structure consists of layered sedimentary schists, limestone, sandstone, and marl (
Specimens of Echinogammarus were collected with a fine-mesh hand net, fixed in 4% formaldehyde in the field, and later examined and dissected under a stereomicroscope. The body length is measured from the basis of antenna 1 to the basis of the telson, keeping holotype male straight (
Holotype. Male, maximum 8.1 mm; Gümüşhane Province, Türkiye (40.081°N, 39.041°E), 17.ix.2019, FFR20000. Paratypes. 21 males and 13 females, FFR20001, same data as holotype.
The new species is named in honour of Prof. Dr Murat Özbek (Ege University, Faculty of Fisheries, Bornova, İzmir). The name is a noun in the genitive singular.
A small species with kidney-shaped eyes, peduncle segments of antenna 1 bearing a group of long setae distal end, setation of antenna 2 moderate on both peduncular and flagellar segments, urosomites flat, uropod 3 parviramous, inner ramus with 1 or 2 distal spines accompanied by 1 or 2 setae; endopod/exopod ratio 0.21; telson with 1 or 2 setae on outer margin and 1 or 2 setae on the inner surface of each lobe. Anterior and posterior margins of pereopods 5–7 have spines and a few setae.
Holotype male. Head (Fig.
Antenna 1
(Fig.
Antenna 2
(Fig.
Gnathopod 1
(Fig.
Gnathopod 2
(Fig.
Pereopod 3
(Fig.
Mandible
(Fig.
Upper lip
(Fig.
Lower lip
(Fig.
Maxilla
(Fig.
Maxilla 2
(Fig.
Maxilliped
(Fig.
Pereopod 4
(Fig.
Pereopod 5
(Fig.
Pereopod 6
(Fig.
Pereopod 7
(Fig.
Uropod 1
(Fig.
Uropod 2
(Fig.
Uropod 3
(Fig.
Urosomites : all urosomites not elevated; urosome 1 without setae or spines; urosomes 2 and 3 bear 1 seta and 1 spine each.
Telson
(Fig.
Coxal plate 1
(Fig.
Coxal plate 2
(Fig.
Coxal plate 3
(Fig.
Coxal plate 4
(Fig.
Coxal plate 5
(Fig.
Coxal plate 6
(Fig.
Coxal plate 7
(Fig.
Epimeral plate 1
(Fig.
Epimeral plate 2
(Fig.
Epimeral plate 3
(Fig.
Pleopods 1–3
(Fig.
Female (Fig.
Antenna 1 less setose than that of male, first peduncle segments with long setae on distal portion, with 17–21 segments on flagellum, 2 segments on accessory flagellum. Gnathopod 1 and 2 similar to that of male, setation more intense on propodus, dactyli of gnathopods 1 and 2 long. Uropod 3 similar to that of male, distal part of peduncle with spines; inner and outer margins of outer lobe more densely setose than male outer lobe with row of 2 spine and 5 or 6 setae in each margin. Telson similar to that of male, each lobe with 1 or 2 distal spines accompanied by 1 or 2 setae longer than the spines.
Oostegites present on gnathopod 2 through to pereopod 5.
The number of flagellar segments of Antenna 1 was determined as 16 in six paratype individuals, while Antenna 2 had nine flagellar segments. The number of setae on the inner and outer edges of the exopod varied between three and six.
In this study, Echinogammarus ozbeki sp. nov. is compared with species from the family Gammaridae, and their similarities and differences are emphasized. At first glance, E. ozbeki sp. nov. closely resembles Gammarus pageti Mateus & Mateus, 1990 and Gammarus balcanicus Schäferna, 1923. Gammarus balcanicus is known for its wide distribution range and intraspecific variation. Karaman and Pinkster, (1987) noted that the endopod (uropod 3) of G. balcanicus collected from Keklik (Erzurum province) is relatively short. Echinogammarus ozbeki sp. nov. is similar to G. balcanicus in having spines on the pereopods, relatively little setation on all appendages, and a short endopod. However, it differs from G. balcanicus in the length/width ratio of the telson lobes, the presence of long setae on the peduncular segments of antenna 1, moderate setation on all extremities, long setae on antenna 2, and setae and spines on the outer and inner margin of the exopod 3.
Echinogammarus ozbeki sp. nov. shows similarities in general body appearance to individuals belonging to the genus Turcogammarus. Turcogammarus aralensis (Uljanin, 1875) and T. spandli (Karaman, 1931) have been recorded from nearby river basins, and one species, T. turcarum (Stock, 1974), has been recorded from Anatolia. E. ozbeki sp. nov. differs from T. turcarum from Mount Ağrı on the Türkiye–Iran border by the absence of long setae on pereopod 7, the presence of short and few setae on the epimeral plate, and the sparser setation of the telson (
Comparison of some distinct characters of Echinogammarus özbeki sp. nov. with species of the genus Echinogammarus distributed in Türkiye.
Echinogammarus ozbeki sp. nov.: a small species; urosome segments without elevation; inner surface of basis of pereopods 5–7 without setae; all extremities without curled setae; all extremities have sparse setae | Echinogammarus antalyae G. Karaman, 1971 | Urosome segments elevated; exopod of uropod 3 with densely plumose setae; basis of pereopods 5–7 with some setal groups on inner surface |
Echinogammarus baliki Özbek & Ustaoğlu, 2007 | Exopod of uropod 3 with plumose setae; urosomite 3 dorsally elevated; outer margin of telson lobes with spines and setae; accessory flagellum with 5 segments; inner surface of gnathopods 1 and 2 with groups of straight and curled setae | |
Echinogammarus foxi (Schellenberg, 1928) | Basis of pereopods 5–7 with some setal groups on inner surface; antenna 2 with weak setation, short setae; flagellum of antenna 1 with 25 segments | |
Echinogammarus ischnus Stebbing, 1899 | Antenna 1, antenna 2, pereopod 3, gnathopods with densely curled setose; telson very short, with 2 lateral spines and 3 dorsal posterior spines; setation absent or very sparse on peraeopods 5–7. | |
Chaetogammarus trichiatus (Echinogammarus trichiatus) Martynov, 1932 | Antenna 2, uropod 3 and gnathopods with dense, curled setae | |
Echinogammarus stocki G. Karaman, 1970 | Antenna 1 with relatively long setae; telson lobes longer than wide; exopod of uropod 3 have dense, long, simple setae | |
Echinogammarus veneris (Heller, 1865) | Antenna 2, exopod of uropod 3 and pereopod 3 have dense, simple setae; basis of pereopod 5–7 have some seta groups on inner surface; urosome segments slightly elevated |
The genus Echinogammarus has been divided into three main groups—E. berilloni group, E. pungens group, and E. simoni group—according to morphological features. Echinogammarus ozbeki sp. nov. differs from the E. berilloni group by the absence of dense setae. Species of the E. berilloni group have a long, dense setae on the different extremites.
Echinogammarus berilloni has dense setae on the metasome and urosome segments. Echinogammarus calvus has long curled setae on the gnathopods. Echinogammarus meridionalis possesses long, straight, and curled setae on antenna 2 and gnathopods. Echinogammarus aquilifer has dense setae only on the flagellum of antenna 2. On the other hand, E. zebrinus bears spines and setae on the urosome and metasome segments. Echinogammarus ozbeki sp. nov. is distinct from other members of the group due to the absence of dense setae or spines on its similar appendages, especially on the metasome segments and the inner surface of the bases of the pereiopods. The shape and setal arrangement of the propodus and weak elevation of the urosome segments in E. cari, and the inflated structure of the peduncle segments of antenna 2, as well as the dorsal elevation of the urosome segments in E. tibaldii (Karaman, 1973) facilitate the differentiation of E. ozbeki sp. nov. from these species. Echinogammarus ozbeki sp. nov. is distinguished from the E. pungens group by the absence of setae on the inner surface of the pereopod basis, the lack of elevation on the urosome segments, the shape of the epimeral plates, and the rare occurrence of spine-setae (
The morphological features of the E. ozbeki sp. nov., which differs from the species belonging to the genus identified so far in Türkiye, are provided in Table
The authors have declared that no competing interests exist.
Ethics committee approval is not required for this study.
No funding was reported.
The author in the article carried out all the sampling, description and writing stages.
Hazel Baytaşoğlu https://orcid.org/0000-0002-9959-1829
All of the data that support the findings of this study are available in the main text.