Sarothrogammarus miandamensis Hou, 2024

Xin, Wenpei, Zhang, Chao, Ali, Abid, Zhang, Xiaoqing, Li, Shuqiang & Hou, Zhonge, 2024, Two new species of Sarothrogammarus (Crustacea, Amphipoda) from Swat Valley, Pakistan, Zootaxa 5432 (4), pp. 509-534 : 513-523

publication ID	https://doi.org/ 10.11646/zootaxa.5432.4.3
publication LSID	lsid:zoobank.org:pub:4EB40A6D-8080-4E3F-9F0C-D055ED8C2C8A
DOI	https://doi.org/10.5281/zenodo.10910597
persistent identifier	https://treatment.plazi.org/id/038487A9-723E-D06E-FF29-FB5EFED7F839
treatment provided by	Plazi
scientific name	Sarothrogammarus miandamensis Hou
status	sp. nov.

Treatment

Sarothrogammarus miandamensis Hou sp. nov.

( Figs 2 View FIGURE 2 , 4–9 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 )

Material examined. Holotype: male (IZCAS-I-A2915-1), 5.5 mm; altitude 1896 m, Miandam , Swat, Khyber Pakhtunkhwa Province, Pakistan (72.56°E, 35.04°N), May 31, 2019, collected by X. Zhang and A. Ali. GoogleMaps Paratypes: one female (IZCAS-I-A2915-2), and three males (IZCAS-I-A2915-3,4,5), same data as the holotype. The GoogleMaps three male paratypes were used for molecular analysis, and the sequences were submitted to GenBank (OR7730536 and OR729702), (OR730535 and OR729701), and (OR730532 and OR729700).

Etymology. The species is named after its type locality, the Miandam Valley.

Diagnosis. Eyes oval; antenna II calceoli absent; gnathopods I–II without medial robust setae on propopus palmar margin; pereopod III with filtrative setae on merus, carpus and propodus; coxal plate of pereopod IV weakly concave; bases of pereopods V–VII expanded; urosomite I with few dorsal setae, urosomites II–III with robust setae; uropod III shorter than uropods I–II, peduncle reaching 0.5 times the length of outer ramus, inner ramus scale-like, with one robust seta on distal margin, outer ramus biarticulate, first article with three groups of robust setae on both margins, second article distinct.

Description of male. Based on holotype (IZCAS-I-A2915-1), 5.5 mm ( Fig. 2A View FIGURE 2 ).

Head ( Fig. 4A View FIGURE 4 ): eyes oval, lateral cephalic lobe rounded. Antenna I ( Fig. 4B View FIGURE 4 ): peduncle articles 1–3 in length ratio 1.0: 0.7: 0.4, with distal setae; flagellum with 26 articles; accessory flagellum with four articles; both primary and accessory flagella with short distal setae. Antenna II ( Fig. 4C View FIGURE 4 ): peduncle articles 3–5 in length ratio 1.0: 3.6: 2.9, with long ventral setae; flagellum with 12 articles, each article with distal setae; calceoli absent. Upper lip ( Fig. 4D View FIGURE 4 ): ventral margin rounded, bearing minute setae. Mandible ( Fig. 4E, F View FIGURE 4 ): incisor of left mandible with five teeth; lacinia mobilis with four teeth. Right mandible incisor with five teeth; lacinia mobilis bifurcate, with small teeth; accessory setal row with seven plumose setae; articles 1–3 of palp in length ratio 1.0: 2.6: 2.2, second article with 12 marginal setae, article 3 with one B-seta, 23 D-setae and four E-setae apically. Maxilla I ( Fig. 4G, H View FIGURE 4 ): asymmetrical, left inner plate with 16 plumose setae; outer plate with nine serrate teeth apically; second article of left palp with six plumose setae and three simple setae apically; second article of right palp with five robust setae and two slender setae. Maxilla II ( Fig. 4I View FIGURE 4 ): inner plate with 22 plumose facial setae in an oblique row; inner and outer plates with long setae apically. Lower lip ( Fig. 4J View FIGURE 4 ): inner lobes absent, outer lobes covered with thin setae. Maxilliped ( Fig. 4K View FIGURE 4 ): inner plate with three robust setae apically, and 13 plumose setae; outer plate with robust setae; palp 4-articulate, article 2 with a row of simple setae on interior side; article 4 hooked.

Pereon. Gnathopod I ( Fig. 5A, B View FIGURE 5 ): coxal plate with one seta on anterior margin and one seta on lower margin; basis sub-linear, with six long setae and five short setae on anterior margin, eight setae on posterior margin; merus with eight long setae on posterior margin; carpus 1.24 times as long as wide, 73% length of propodus, ventral margin bearing two clusters of setae; propodus 2.03 times as long as wide, palmar margin crenellated only in its proximal (angular) part, with nine setae and defined by nine robust setae; dactylus reaching approx. 53% length of propodus, posterior margin arc-shaped. Gnathopod II ( Fig. 5C, D View FIGURE 5 ): coxal plate bare; basis with five long setae and five short setae on anterior margin, posterior margin with eight long setae, two short setae; merus with two clusters of setae on posterior margin; carpus with two and five clusters of setae on anterior and posterior margins, respectively; propodus 2.1 times as long as wide, subrectangular, with seven robust setae and seven slender setae on palm margin; dactylus reaching approx. 50% length of propodus.

Pereopods III–VII ( Fig. 6A–E View FIGURE 6 ). Pereopod III ( Fig. 6A, I View FIGURE 6 ): coxal plate bearing two setae and one seta on anterior and lower margins, respectively; basis elongated, with setae along anterior and posterior margins; merus with a row of filtrative setae on posterior margin, two robust setae and two slender setae on anterior margin; carpus with a row of filtrative setae on posterior margin, anterodistal corner with two robust setae accompanied by three slender setae; propodus with a row of filtrative setae on posterior margin and two robust setae on posterodistal corner; merus, carpus, and propodus in length ratio 1.0: 0.8: 0.7; dactylus with two setae at hinge of unguis. Pereopod IV ( Fig. 6B, J View FIGURE 6 ): coxal plate concave, bearing two setae on anterior margin; basis with three long and two short setae along posterior margin and two robust setae on posterodistal corner; merus with three clusters of short straight setae on posterior margin and two setae on anterior margin, anterodistal corner with two robust setae accompanied by slender setae, posterodistal corner with one robust seta accompanied by slender setae; carpus and propodus with robust setae accompanied by slender setae on posterior margins; merus, carpus, and propodus in length ratio 1.0: 0.7: 0.7; dactylus with one plumose seta on anterior margin, two setae at hinge of unguis. Pereopod V ( Fig. 6C, K View FIGURE 6 ): coxal plate with no setae; basis expanded, with six robust setae on anterior margin, anterodistal corner with two robust setae accompanied by one short seta, posterior margin with a row of 13 setae; merus with two clusters of setae on anterior margin and one robust seta accompanied by one short seta on posterior margin, anterodistal corner with one robust seta accompanied by short setae, posterodistal corner with two robust setae accompanied by slender setae; carpus and propodus with three to four groups of robust setae accompanied by short setae on anterior margins; merus, carpus, and propodus in length ratio 1.0: 1.4: 1.2; dactylus with two setae at hinge of unguis. Pereopod VI ( Fig. 6D, L View FIGURE 6 ): coxal plate bearing three setae on posterior margin; basis elongated, with eight robust setae on anterior margin, anterodistal corner with two robust setae, and one robust seta on posterodistal corner; posterior margin with four setae; merus with three robust setae accompanied by short setae on anterior margin and one robust seta on posterior margin, anterodistal corners with three robust setae and posterodistal corner with two robust setae accompanied by two short setae; carpus and propodus with groups of robust setae accompanied by short setae on anterior and posterior margins; merus, carpus, and propodus in length ratio 1.0: 1.4: 1.2; dactylus with two setae at hinge of unguis. Pereopod VII ( Fig. 6E, M View FIGURE 6 ): coxal plate with three setae on posterior margin; basis with five robust setae and one short seta on anterior margin, anterodistal corner with two robust setae accompanied by short setae, and posterodistal corner with one robust seta accompanied by short setae, posterior margin with a row of 18 setae; merus with two groups of robust setae on anterior margin, anterodistal and posterodistal corners with three and two robust setae accompanied by short setae, respectively; carpus and propodus with groups of robust setae accompanied by short setae on anterior margins, respectively; merus, carpus, and propodus in length ratio 1.0: 1.4: 1.0; dactylus with two setae at hinge of unguis.

Coxal gills: present on gnathopod II and pereopods III–VII; sternal gills absent; coxal gill of gnathopod II and gill of pereopod IV longer than bases; gills of pereopods III, VI and VII a little shorter than bases; gill of pereopod V equal length of basis.

Pleon. Epimeral plates ( Fig. 4N–P View FIGURE 4 ): plate I ventrally rounded, with four setae on ventral margin, five setae on posterior margin; plate II posterior corner blunt, with two robust setae on ventral margin and seven setae on posterior margin; plate III with two robust setae on ventral margin and three setae on posterior margin.

Pleopods I–III ( Fig. 4M View FIGURE 4 ): similar to each other. Both rami subequal, with plumose setae.

Urosome. Urosomites I–III ( Fig. 4Q View FIGURE 4 ): urosomite I with two setae on dorsal margin; urosomite II with two robust setae accompanied by one short seta on dorsal margin; urosomite III with four robust setae on dorsal margin.

Uropods I–III ( Fig. 6F–H View FIGURE 6 ): uropod I peduncle without basofacial seta, with two and three robust setae on inner and outer margins, inner and outer distal corners with one robust seta, respectively; inner ramus approximately 0.79 times as long as peduncle, with two robust setae on inner margin, one robust seta on outer margin, and five robust setae distally; outer ramus slightly shorter than inner ramus, with two robust setae on inner margin and five robust setae distally. Uropod II peduncle bearing two robust setae on inner margin and one robust seta on each distal corner; inner ramus with one robust seta on inner and outer margins, respectively, and five robust setae distally; outer ramus slightly shorter than inner ramus, with two robust setae on inner margin and four robust setae distally. Uropod III peduncle 0.46 times as long as outer ramus, inner ramus reduced, scale-like, with one robust seta on distal margin; outer ramus 2-articulate, first article of outer ramus with robust setae on inner and outer margins, terminal article 0.13 times of the first article, with two distal setae.

Telson ( Fig. 4L View FIGURE 4 ): deeply cleft, 1.2 times as long as wide, each lobe with four or five robust setae distally.

Description of paratype female (IZCAS-I-A2915-2), 5.5 mm ( Fig. 2B View FIGURE 2 ).

Head. Antennae and mouthparts ( Fig. 7A–J View FIGURE 7 ) similar to those of male.

Pereon. Gnathopod I ( Fig. 8A, B View FIGURE 8 ): coxal plate with three setae on lower margin; basis sub-linear, with five long setae and four short setae on anterior margin, seven unequal setae on posterior margin and four setae on posterodistal corner; merus with 18 setae on posterior margin; carpus 1.38 times as long as wide, 70% length of propodus, ventral margin bearing a row of setae; propodus 1.90 times as long as wide, palmar margin crenellated only in its proximal (angular) part, with nine setae and defined by six robust setae; dactylus reaching approx. 50% length of propodus, posterior margin arc-shaped, with one seta. Gnathopod II ( Fig. 8C, D View FIGURE 8 ): coxal plate with two setae on lower margin; basis with three setae on anterior margin, ten setae on posterior margin; merus with nine setae on posterior margin; carpus with clusters of setae on posterior margin; propodus 2.25 times as long as wide, with three robust setae and eight slender setae; dactylus reaching approx. 39% length of propodus.

Pereopods III–VII ( Fig. 9A–E View FIGURE 9 ): similar to those of male, except pereopod III with filtrative setae on posterior margin of merus but short setae on posterior margins of carpus and propodus.

Oostegite ( Figs. 8E View FIGURE 8 , 9F, H, J View FIGURE 9 ): present on gnathopod II to pereopod V, longer than wide, and with 15–22 fine smooth-edged setules; smallest in pereopod V.

Urosome. Uropods I–III ( Fig. 7M–O View FIGURE 7 ): uropod I peduncle without basofacial seta, with two robust setae on inner margin, inner and outer distal corners with one robust seta, respectively; inner ramus approximately 0.76 times as long as peduncle, with two robust setae on inner margin, and five robust setae distally; outer ramus slightly shorter than inner ramus, with two robust setae on inner margin and five robust setae distally. Uropod II peduncle bearing two robust setae on outer margin and one robust seta on outer distal corner; inner ramus with two robust setae on inner margin, and five robust setae distally; outer ramus slightly shorter than inner ramus, with two robust setae on inner margin and five robust setae distally. Uropod III peduncle 0.56 times as long as outer ramus, inner ramus scale-like, with one robust seta on distal margin; outer ramus 2-articulate, first article of outer ramus with robust setae on inner and outer margins, terminal article 0.11 times of the first article, a little shorter than adjacent robust setae with two distal setae.

Telson ( Fig. 7K View FIGURE 7 ): deeply cleft, 0.87 times as long as wide, each lobe with four or five distal robust setae.

Habitat: This species was collected from a small water body (about 1 square meter) beside a brook.

Remarks: The new species is assigned to the genus Sarothrogammarus according to the filtrative setae on pereopod III and the scale-like inner ramus of uropod III. It is not a member of the genus Comatogammarus because pereopod IV lacks filtrative setae. It is not assigned to the genus Barnardiorum because the second article of the outer ramus in uropod III is distinct rather than vestigial.

Sarothrogammarus miandamensis sp. nov. differs from Sarothrogammarus yiiruae in the following features (features of S. yiiruae in parentheses): eyes oval (eyes absent); pereopod III with filtrative long setae on merus, carpus and propodus (pereopod III without filtrative setae due to its subterranean-like habitat); pereopods V–VII bases expanded (bases narrow), and urosomites I–III with robust setae and slender setae on dorsal margin (with slender setae only).