Gammarus shirazinus, Zamanpoore, Mehrdad, Grabowski, Michal, Poeckl, Manfred & Schiemer, Friedrich, 2010

Zamanpoore, Mehrdad, Grabowski, Michal, Poeckl, Manfred & Schiemer, Friedrich, 2010, Two new Gammarus species (Crustacea, Amphipoda) from warm springs in the south-east pre-alpine area of the Zagros, Iran: habitats with physiological challenges, Zootaxa 2546, pp. 31-51 : 33-41

publication ID	https://doi.org/ 10.5281/zenodo.196755
DOI	https://doi.org/10.5281/zenodo.3509244
persistent identifier	https://treatment.plazi.org/id/EF5DD93B-FF8E-FFA9-94B2-4AD0E352FBA3
treatment provided by	Plazi
scientific name	Gammarus shirazinus
status	sp. nov.

Treatment

Gammarus shirazinus View in CoL n. sp.

( Figs. 2–5 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Gammarus syriacus Chevreux, 1895 View in CoL , [in Mateus & Mateus 1990: 280].

Material Examined. Many males and females. Male holotype, body length 22 mm, February and August 2007, coll. M. Zamanpoore. Locus typicus: Pole-Berenji spring, 10 km S of Shiraz, Fars Province, Iran (2927´N, 5231´E), Altitude 1490 m. Paratypes, many males and females; same date and locality. Additional samples: Barme-Delak spring, 18 km SE of Shiraz, (2933´N, 5242´E), Altitude 1467 m.; Barme-shur spring, 17 km S of Shiraz, (2928´N, 5241´E), Altitude 1463 m.; Barme-Tarkoshte spring, 17 km SE of Shiraz, (2934´N, 5240´E), Altitude 1472 m.; Kaftarak, 16 km SE of Shiraz, (2935´N, 5239´E), Altitude 1473 m.; Niriz, 200 km SE of Shiraz, (2912´N, 5420´E), Altitude 1603 m.; Pire Bano spring, 11 km SW of Shiraz (2931´N, 5227´E), Altitude 1492 m.; Pire Gheibi spring, 12 km SW of Shiraz (2931´N, 5227´E), Altitude 1492 m.; Se Barm spring, 14 km E of Shiraz (2935´N, 5240´E), Altitude 1488 m.; All specimens including type series are kept in the amphipod collection of the Museum of Fars Research Centre of Agriculture and Natural Resources (FARSAGRES), Shiraz, Iran. Holotype is deposited in the Zoological Museum of the University of Amsterdam ( ZMA, Amph. 206057, 2008).

Diagnosis. A medium species. In general, this species can be distinguished from other adjacent species by a combination of the following characters: (1) highly setose antenna 2 and pereopods 5–7 posterior margin, (2) antenna 1 with two spines on the ventro-distal of first peduncle, (3) no setae on postero-distal corner of basis pereopod 6 and 7, and (4) longer fine setae on posterior pereopods 5–7 basis.

Etymology. The species' name shirazinus is made from the name of Shiraz, Capital of Fars Province. The type locality is in a very close distance southwards.

Description. Description is based on examination of the holotype, 10 male and one female paratypes.

Male. Maximum body length (based on 40 individuals) 23 mm.; lateral cephalic lobes rounded, anterior lower part of the head not extended nor elongated; eyes reniform, of the medium size (the same length as the diameter of the first segment of antenna 1, length of which twice or less than twice as wide ( Fig. 2 View FIGURE 2 D).

Antenna 1: long, about half the body length; peduncle segment 3 less than half the length of the first and the second segment; a group of some 3–5 setae on lateral sides of the first peduncle tip, and two spines on its ventral side ( Fig. 2 View FIGURE 2 B); 2–3 groups of short setae (the same length as the width of the related segment) on ventral of the second peduncle segment and one group on the third; main flagellum with 30–36 and accessory flagellum with 3 segments, respectively, with very short simple setae in groups of 3–5 on each side ( Fig. 2 View FIGURE 2 A).

Antenna 2: Gland cone do not reach the distal end of the third peduncle segment; peduncle segments 4 and 5 of the same length, with groups of long setae (up to three times the length of the diameter of the segments); flagellum with 10–16 segments; long setae, the longest of which are set at the proximal segments, groups of setae sub-marginal to the tip of each flagellar segment at both outer and inner surfaces, a row of setae sub-marginal to the ventro-distal surface of each segment, flag-like brush not formed; calceoli present ( Fig. 2 View FIGURE 2 C).

Mandible: With well developed incisor processes and lacinia mobilis, a plumose long spine row and a ridged molar process ( Fig. 2 View FIGURE 2 E). First segment of mandible palp not armed; ventral setae on the second segment comprised of 3–4 separated short setae (shorter than the width of the segment) at the proximal and 6 longer setae (as long as to slightly longer than-three times the width of the segment) implanted very close to each other at the distal; a comb-like row of 28–32 D-setae, 5 long E-setae, a groups of B-setae (5) and a group of A-setae (3) on the external surface of the third segment ( Fig. 2 View FIGURE 2 F).

Labium: Simple; a group of short setae on the inner margin of the apices, a group of bristles on more proximal of the apex of the inner lobe, and a group of very fine bristles on the outer margin.

Maxilla 1: long plumose setae on inner lobe; outer lobe with stout serrate spines; apex of the left palp with 6 median spines accompanied by 3 median setae (2 times longer than spines), one longer separate subapical spine on distal outer corner ( Fig. 2 View FIGURE 2 H), right palp with six robust tooth-like spines on the apex, one longer separate spine in a sub-apical position on its distal outer corner and one longer setae between them ( Fig. 2 View FIGURE 2 I).

Maxilliped: Distal margin of exopodite with a row of three strong teeth and 8 longer setae; a single spine proximal to the most interior teeth, a row of three setae parallel to the long axis close to the single spine, a row of setae extended from proximal to distal on interior margin, shorten gradually, becomes sub-marginal under the distal apex, ( Fig. 2 View FIGURE 2 G); endopodite with a row of long plumose setae distally, losing plumosity and shortening interiorly, merging with a row of inferior spine-teeth proximally, which gradually shorten; palp well developed.

Gnathopod 1: Distal of coxal plate with the same width as proximal, corners rounded, one seta at postero-distal and 1–2 setae at antero-distal corner, 1–2 longer setae at distal sub-marginal surface of the plate; basis slightly expanded at 1/3rd, getting narrower proximally; posterior margin of carpus and merus with groups of setae which are plumose on carpus; propodus pyriform, palm oblique with both medial palmar and palmar angle spines, propodus with 4–5 groups of small spines at posterior margin and 2 groups of longer setae (2–3 each) on posterior sub-margin, dactylus long, a group of four setae very close to medial palmar spine, two groups of shorter setae at anterior margin, 2 rows of short setae (5 groups each) on propodus face ( Fig. 3 View FIGURE 3 A).

Gnathopod 2: Distal part of coxal plate with almost the same width as the proximal part, one seta at postero-distal and 2 setae at antero-distal corner, 2–3 setae on the distal sub-margin of the plate surface; propodus sub-rectangular, more elongated than propodus of gnathopod 1; palm oblique with both robust medial palmar and palmar angle spines (2), 3–4 additional small spines close to the palmar angle spines; a group of long setae attached to the base of medial palmar spine, two rows of long setae (of 4–5 groups each) on the propodal surface, but no groups on anterior margin ( Fig. 3 View FIGURE 3 B).

Pereopod 3: Coxal plate rounded at antero-distal corner, posteriorly concave and anteriorly convex margin, with a setae at postero-distal corner, and a longer setae on the surface of the plate; posterior margin of basis-carpus with groups of setae, length of which about 1 to 1.5 times the diameter of the segments in basis and ischium; in merus and carpus they are in dense groups, 2–3 times longer than the diameter of the segments; merus anterior margin with 2–3 groups of few setae and a spine, a group of long setae and a spine at anterior tip; carpus posterior margin with one spine among some of its 8–9 groups of setae, and a long spine and a group of longer setae implanted on both its anterior and posterior tip; 5 groups of one spine and many long setae on propodal posterior margin ( Fig. 3 View FIGURE 3 C).

Pereopod 4: The lengths of setae are shorter, and the number of setae and groups of setae are lower than those in pereopod 3. Two small setae on antero-distal and 4 at postero-distal margin of coxal plate; merus anterior margin with two groups of short setae and one spine, one long spine among a group of setae implanted at anterior tip; carpus with two spines in some groups of posterior margin armature ( Fig. 3 View FIGURE 3 D).

Pereopod 5: Basis sub-rectangular, protruding lobe developed at postero-distal, about 10 setae at posterior margin which are long for this place (as long as or longer than the length of ischium), anterior basis with a marginal row of 1–2 groups of setae (2–3 each) and 3–4 spines; small spines and longer setae as long as the segment width on merus, but more than 2 times longer than the segment width on carpus, propodus with 5 rows of spines (3–3–3–3–2) on anterior margin and long setae on posterior ( Fig. 4 View FIGURE 4 A).

Pereopod 6: Longer than pereopod 5; basis more slender, postero-distal protruding lobe weakly developed; setae on all segments much longer than those of pereopod 5, nearly 3 times the length of the related segments; 6 rows of spines on propodus anterior margin ( Fig. 4 View FIGURE 4 B).

Pereopod 7: Basis wider proximally than distally; postero-distal lobe weakly developed, as an obtuse corner, some 15 setae on posterior margin, slightly shorter than the length of ischium; merus and carpus anterior margin with long spines and very long setae (up to 4 times the width of the related segment), posterior margin with less numerous and shorter setae; propodus with shorter spines (2–3–3–3–3–2) and setae on anterior margin, and setae only on posterior; posterior tip of propodus with 2 spines mixed with a group of longer setae ( Fig. 4 View FIGURE 4 C).

Uropod 3: Endopodite about 3/4 (Mean = 0.73, SD = 0.02) of the exopodite; setae on both rami long but shorter on proximal part of exopodite, many plumose setae on outer margin of both exo- and endopodite, three groups of long robust spines sometimes with few setae implanted on tip of basis; external margin of exo- and endopodite armed with long spines implanted in intervals ( Fig. 4 View FIGURE 4 F).

Epimeral plates: Epimeral plate 1 rounded with a tiny pointed node at postero-inferior corner, some 14 setae on antero-inferior corner; anterior margin of the second plate rounded and slightly pointed at posterior corner; third plate moderately pointed; epimeral plates 2 and 3 with 1–2 spines and a few longer setae on inferior sub-margin, one-two long setules on distal posterior margin in all 3 plates, posterior dorsal margin of metasomites 2 and 3 with a row of long setules ( Fig. 4 View FIGURE 4 D).

Telson: Elongated, lobes about twice longer than broad; a group of two–three long and robust spines and some 7 long setae on the tip; dorsal surface of the lobes with 3–4 groups (of 2–4) setae ( Fig. 1 View FIGURE 1 J).

Urosomites: posterior dorsal surface of urosome segments without elevation, dorsal armature of 1–2 spines on latero-dorsals and 2 spines on mid-dorsal, mixed with some short setae ( Fig. 4 View FIGURE 4 E).

Female. The female is smaller than male (12 mm).

Palm less oblique in propodus of gnathopod 1; no medial palmar spine, a long palmar angle spine, 2–3 spines at posterior palmar margin, and a group of setae at medial palm.

Propodus of gnathopod 2 sub-rectangular, without the medial palmar spine; 3 palmar angle spines, a group of setae at medial palm, posterior palmar margin without spines.

Propodus of gnathopod 1 and gnathopod 2 is smaller than in males, compared to the other segments and the whole appendage than in males.

Proximal 3/4th in bases of gnathopod 1 and gnathopod 2 are not wider than their distal.

Bases of pereopods 5–7 are less elongated compared to males, with distinctly convex angles at the middle of posterior margin ( Fig. 5 View FIGURE 5 A–C); shorter setae on distal segments.

Epimeral plates 2 and 3 without setae on distal sub-margin, showing only few spines ( Fig. 5 View FIGURE 5 D). Oostegite 1 is illustrated in Figure 5 View FIGURE 5 E.

Cuticular ultrastructure. Cuticular polygons of head capsule show both linear (L-type) and scattered (Stype) types of pore arrangements ( Fig. 6 View FIGURE 6 A); distances between lines were 0.97–2.22 (Mean = 1.56, SD = 0.24); density of pores in L-type polygons were 54–75 pores per 25 µm2 (Mean = 64, SD = 5.04) while S-type polygons had higher densities of 104–170 pores per 25 m 2 (Mean = 131, SD = 14.72), arranged in a specific cluster-shaped pattern ( Fig. 6 View FIGURE 6 C).

Remarks. Despite of some similarities among all populations of the whole area, one may not encounter with much difficulty in identifying G. shirazinus from other adjacent species, using the clear distinctive feature of having 2 spines on the first peduncle of antenna 2. Comparisons of the new species with other closely related species are given below.

Mateus and Mateus (1990) examined samples from the very same area (material from Crustacean Collection of the Natural History Museum of Vienna (NHMW), coll. no. 4867, one male, one female) identified them as Gammarus syriacus Chevreux, 1895 . Re-examination of these samples showed that they are completely identical to our samples, especially in having the antenna 1 spines. Here is a comparison of the description of G. s y r i a c u s from Syria and Lebanon given in Karaman and Pinkster (1977, pp. 60–64, Figs. 24A–L; 25A–L) with our newly described species.

In G. syriacus antenna 2 peduncles and flagellum bear short setae, and the gland cone is only half of the third segment, pereopod 3–7 have shorter setae on all segments, pereopod 7 posterior distal protruding lobe is less developed, epimeral plates 1–3 postero-inferior corners are elongated (sabre shaped) and sharply pointed, dorsal humps are quite well developed, and telson is elongate with much short setae. In G. s h i r a z i n u s all these characters are clearly different. Hence, it seems quite evident that these populations are not con-specific with G. syriacus , and we are dealing with two distinctly separate species.

Gammarus shirazinus View in CoL lives in a region close to localities of G. crinicaudatus Stock et al., 1998 View in CoL (holotype, ZMA Crust amph 201937). The new species differs from it by having 2 spines on ventro-distal margin of antenna 1 first peduncle segment, longer gland cone (ca. 2/3rd the length of the third peduncle segment) and setae on both peduncle and flagellum and having calceoli on antenna 2, no setae on postero-distal corner of pereopod 7 basis, much longer fine setae on posterior margin of bases and longer setae and spines on distal segments of pereopods 5–7, longer setae on inferior margin of epimeral plates 2–3, telson (more than the length of telson itself), and posterior dorsal margin of urosome. There is also no distinct space between proximal and distal setae on the second segment of palp of mandible, and 28–32 D-setae on inferior margin of the third in the new species, while a clear empty distance and about 20 D-setae are seen in G. crinicaudatus View in CoL .

G. komareki Schaeferna, 1922 View in CoL , widely distributed in the country, shares with G. shirazinus View in CoL the feature of having a long antenna 1 appendage, long antenna 2 setation, long setae on pereopod 3, similar shape of basis in pereopods 5–7, and long uropod 3 endopodite. On the other hand, it has small eyes, no spines on antenna 1, short gland cone, “very densely setose” with curled setae and slightly swollen and dorso-ventrally compressed antenna 2 flagellum, more numerous distal long setae on second segment and more (40) D-setae on the third segment of palp of mandible, less setose pereopod 4 and pereopods 5–7 distal segments, shorter setae on inferior margin of epimeral plates 2–3, less setation on uropod 3, and much shorter setae on telson, all of which make it totally different from this new species.

The only reported species with a similar feature to the two spines on peduncle antenna 1 in all fresh water Gammarus species is G. bakhteyaricus Khalaji-Pirbalouty & Sari, 2004 , with three structures on the same place on antenna 1, unless those are called as “short robust setae” by the authors; however we suggest them as the same structure, well recognised as true “spines”, an absolutely rare and unique feature in fresh water gammarids. Despite this similarity, the two species has many differences, among them are small eyes, poorly setose antenna 2, different pattern of setation in gnathopod 1 and gnathopod 2, poorly setose pereopods 5–7 and telson, elongated and tapered pereopod 7 basis with some setae on postero-distal corner, elevated dorsal urosomites, and very short setae on inferior margin of epimeral plates 2–3 ( Khalaji-Pirbalouty & Sari, 2004; Figs. 5–7 View FIGURE 5 View FIGURE 6 View FIGURE 7 ).

G. qiani Hou & Li, 2002 View in CoL , described from Yunnan Province, China, has the similarity of setose impression in pereopods 5–7, resembling it to G. shirazinus View in CoL , but shows many characters differentiating it, including weekly setose peduncles of antenna 1, moderately setose peduncles and flagellum of antenna 2, longer antennal gland cone reaching to the tip of the next peduncle segment, only moderately setose pereopod 3–7, not developed postero-inferior lobe and having corner setae in pereopod 7, only few short setae on an incompletely cleft telson, epimeral plates not pointed, and poorly setose entire uropod 3 with an endopodite which is only slightly shorter than exopodite ( Hou & Li 2002; Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ).

G. translucidus Hou et al., 2004 View in CoL , (from Guizhou Province, China) is also similar regarding the high setosity of the peduncle 4 and 5 of antenna 2 and pereopods 5–7 as well, short antennal gland cone, and poorly developed protruding lobe in pereopod 7, but a cave-dwelling amphipod, it has some important differences with G. shirazinus View in CoL including lacking the eye, short setae on pereopod 4, setae on postero-inferior corner of pereopod 7 basis, short setae on the telson, and incomplete cleft telson, according to Hou et al. (2004), figs. 1– 4.

Ecology. Site description. This new species inhabits several springs and rivers including the locus typicus (Pol'e Berenji) which lies at the bottom of a small chain of hills (1500–2100 m above sea level) at the very beginning of first order brooks in a region very close (10 km aerial and 22 km land distance) to Shiraz, capital of Fars Province in southward direction. The shallow (20–40 cm) spring merges shortly (100 m) with a deeper stream running towards a plain, where it is used up almost entirely in farms during the spring and summer. Other loci, not too far from here, are shown in Figure 1 View FIGURE 1 .

The spring bed constitutes small sized gravel (Mean diameter = 11.5 mm) and fine sand at the base. Aquatic flora is restricted to Ceratophyllum demersum L. and Nasturtium officinale L., poorly inhabiting the spring, but in much dense populations in the continuing river. Few old trees were previously grown in the margins of the brook, making the desired shadow for gammarids on hot summer days. Unfortunately, all of them were cut shortly before our last sampling in summer 2007 by the nearby village farmers who - in hope of increasing water discharge - have dug the spring canal.

Ecological data. Mean values for width and depth were 300 cm (SD = 55) and 19 cm (SD = 9) in winter, and 100 cm (almost uniform) and 25 cm (SD = 12) in summer. Water current velocity and discharge were 0.3 m /s and 27dm3/s, respectively, in February, while there was no current/discharge in August.

Winter and summer records for water temperature were 21.6°C and 22.4°C, and for dissolved oxygen were 6.5 and 4.4 mg /dm3, respectively at the spring source. Air temperature raised from 15°C to 36°C at the same time, while its absolute maximum records in last 37 years were measured up to 43°C (FRMD 2009a). Other environmental factors measured in winter and summer in the spring are summarized in table 1. Details of some ecological data for other localities are presented in Table 2.

G. shirazinus G. loeffleri

winter summer winter summer

pH 7.3 7.5 7.8 8.0 alkalinity (mval/dm3) 3.26 3.28 4.02 3.96 electrical conductivity (µS/cm) 1686 1920 575 564 [Na] (mg/dm3) 213.8 251.8 30.7 30.1 [K] (mg/dm3) 3.3 2.9 1.8 1.5 [Ca] (mg/dm3) 75.0 77.3 65.8 65.8 [Mg] (mg/dm3) 35.3 38.4 15.0 15.5 [Cl] (mg/dm3) 335.2 426.5 37.6 35.6 ([SO4 2-] (mg/dm3) 119.3 126.9 36.5 36.0 Salinity (sum of ions) 781.9 923.8 187.4 184.5