First record of the Short-tailed Pipefish , Microphis brachyurus lineatus ( Kaup , 1856 ) ( Syngnathidae , Nerophinae ) , for Suriname

The occurrence of the pipefish Microphis brachyurus (Bleecker, 1854) in Suriname is reported here for the first time. The records include 3 specimens from the lower Suriname River at Overbridge, collected from a reach in the river with fresh water, without brackish tidal influence and dense aquatic and flooded shore vegetation.


Introduction
The taxonomy of Microphis brachyurus (Bleeker, 1854) sensu lato is still in flux.Depending on the author, it represents either a single species with 4 subspecies (e.g., Dawson 1984) or 4 species (e.g., Fricke et al. 2018).Until comprehensively investigated, we tentatively follow the last detailed review by Dawson (1984), separating the taxon in 4 subspecies: Microphis brachyurus brachyurus (Bleeker, 1854)  Microphis brachyurus lineatus occurs in brackish waters and freshwater rivers in coastal areas from Brazil to Mexico (Ferraris 2003).It was reported for Guyana by Eigenmann (1912).For French Guyana, records have not been published so far in the scientific literature, but we are aware of a specimen in the ichthyological collections of the California Academy of Sciences (CAS-ICH 238098).The respective specimen was collected (probably in 2015) from the Comte River close to the village Cacao.There are no records of Microphis brachyurus reported for Suriname.By collecting 3 specimens in February 2018 from the Para District, we were able to close at least this gap.

Methods
Specimens of M. b. lineatus were collected using a small seine of 2 × 1.2 m with 5 mm mesh size.Soon after catching, the specimens were photographed in a small photo tank using a Canon EOS 80D with a SIGMA Macro 105 mm f/2.8 macro lens.Collected fish were euthanized using an overdose of clove oil prior to fixation.The pipefish were either preserved in pure ethanol or fixed with 4% formalin and later transferred into 70% ethanol.The specimens are stored in the ichthyological collection of the Deutsches Meeresmuseum, Stralsund, Germany (DMM).Fixed specimens were photographed with the extended focus technique using a Canon EOS 80D with a CANON MP-E 65 mm f/2.8 a-5x macro lens via the dedicated software Canon Utilities; images were stacked with Helicon Focus 7.0 (HeliconSoft, Kharkiv) and stitched with Hugin 2016.2.0 (hugin.sourceforge.net).Cropping without alteration on the specimen was performed using GIMP 2.8.22 (www.gimp.org).
Collecting was performed in cooperation with the Center for Agricultural Research in Suriname (Celos) and Department of Biology, Anton de Kom University of Suriname; part of the samples was exported under the permit #183/18 issued by the Ministry of Agriculture, Animal Husbandry and Fisheries of Suriname.

Results
New records (Fig. 1).Suriname: Para District: lower Suriname River close to Overbridge Resort, at a sand bank in the middle of the river (05°32ʹ05ʺ N, 055°02ʹ36ʺ Live pictures were taken on the day of capture (Fig. 2).All specimens were collected in vegetation; at the sandbank in the middle of the river in flooded stands of Eleocharis Brown and Montrichardia Crueger (Fig. 3) and submerged Mayaca fluviatilis Aublet, and in dense aquatic vegetation, predominantly consisting of Cabomba Aublet, along the southwestern bank of the Overbridge Resort.The area in which the specimens were collected is influenced by tidal changes in water level, but the water is fresh (< 300 mg/L Cl) year-round (Fig. 1).
Two specimens, both female, were euthanized using clove oil: one specimen was fixed in 100% ethanol (DMM IE/14824, 97.7 mm SL, Table 1), the second specimen was fixed in 4% formalin and later transferred into 70% ethanol (DMM IE/14883, 103.4 mm SL, Table 1, Fig. 4).The third specimen was kept alive and was observed for 1 month in a 45 × 30 × 30 cm aquarium with some artificial plants added for shelter, but no bottom substrate.No other fishes were present in the tank.The M. b. lineatus specimen accepted both live Culex Linnaeus, 1758 larvae at the water surface and chironomid larvae on the bottom of the tank.However, most of the time the specimen was feeding or resting near the water surface in between the artificial plants and this behaviour is confirmed by observations in the wild in French Guiana where M. b. lineatus was observed swimming at the water surface in mangroves (G.Quartarollo personal communication).While M. b. lineatus shows a rather surface-oriented behaviour, the second syngnathid in the area, the smaller, syntopic pipefish Pseudophallus brasiliensis Dawson, 1974 lives in the benthic zone (Mol 2012b).
Identification.Five species out of 3 genera of pipefish have been recorded from freshwater in South and Central America (Ferraris 2003).The body ridge configuration (Fig. 4) is diagnostic for Microphis, with the anterior ridge running ventrally at the level of dorsal fin origin and thus overlapping with the posterior ridge (Dawson 1984: fig. 1).Within this genus, a single species was reported for South America.Furthermore, Dawson (1984) provided a worldwide key for the genus Microphis, in which the species keys out as M. brachyurus lineatus, by having a distinct longitudinal opercular ridge accompanied by a supplemental ridge, scutella without keel, snout depth 8.1-8.7 times the snout length, snout length 1.62-1.69times the head length, and 18 trunk rings (Table 1).
from the central Indian Ocean and central Pacific Ocean, M. b. aculeatus (Kaup, 1856) from the eastern Atlantic Ocean, M. b. millepunctatus (Kaup, 1856) from the western Indian Ocean, and M. b. lineatus (Kaup, 1856) from the western Atlantic Ocean.

Figure 1 .
Figure1.Map of the lower Suriname River, Suriname, showing collection localities of the short-tailed pipefish Microphis brachyurus lineatus at Overbridge (at km 105) and the maximum limit of salt water (300 mg/L Cl -) intrusion at km 90 (Paranam).River kilometer numbers are measured along the thalweg and begin at zero, designated as the river mouth at the 15 m depth contour at low-water spring tide, and increase in upstream direction.

Figure 3 .
Figure 3. Vegetated sand bank in the middle of the Suriname River close to Overbridge, Suriname, with the emergent aquatic macrophytes Eleocharis and Montrichardia and submerged Mayaca fluviatilis.