Jesogammarus (Jesogammarus) hebeiensis, Hou & Li, 2004
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publication ID |
https://doi.org/ 10.5281/zenodo.13244641 |
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DOI |
https://doi.org/10.5281/zenodo.13244812 |
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persistent identifier |
https://treatment.plazi.org/id/28376877-A178-FFBC-18C0-FD95FC3B493F |
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treatment provided by |
Felipe |
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scientific name |
Jesogammarus (Jesogammarus) hebeiensis |
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sp. nov. |
Jesogammarus (Jesogammarus) hebeiensis View in CoL , new species
( Figs. 5-8 View Fig View Fig View Fig View Fig )
Material examined. – Holotype – male (IZCAS-I-A0087), 13.2 mm, Lake Baiyangdian (38.5 oN, 115.55 oE), Hebei Province, coll. Shuqiang Li, 19 Mar.1989.
Paratypes – 19 males ( IZCAS) , 10 males ( ZRC), same data as for holotype .
Diagnosis. – Mandibular palp article 1 with two distal spines. Pleonites 1-3 without dorsomarginal spine. Inner lobes of lower lip distinct. Uropod 3 lanceolate, inner ramus about one-third of outer ramus. Telson longer than maximum basal width.
Description. – Male, body length 13.2 mm. Head ( Fig. 5A View Fig ): eyes medium in size, inferior antennal sinus distinct. Antenna 1 ( Fig. 5D View Fig ): peduncular articles 1-3 in length ratio 1: 0.82: 0.53, with several short setae, peduncular article 1 lacking or with one posterodistal spine; flagellum with 29 articles, most with aesthetascs; accessory flagellum with five articles. Antenna 2 ( Fig. 5E View Fig ): peduncular articles 4 and 5 subequal in length, with some short setae; flagellum with 16 articles, with calceoli.
Upper lip subrounded ( Fig. 5G View Fig ), with minute setae. Mandibles ( Figs. 5M, L View Fig ): left incisor with five teeth; lacinia mobilis with four dentitions; molar with one seta; article 1 of palp with two or three spines distally, article 2 with five submarginal spines and nine marginal setae and 12 submarginal setae, article 3 about 85% of article 2 in length, with four groups of A-setae; right incisor with four teeth; lacinia mobilis bifurcate. Lower lip ( Fig. 5F View Fig ): inner lobes distinct. Maxilla 1 asymmetrical ( Figs. 5I, J View Fig ), inner plate with 20 plumose setae; outer plate with 11 serrated spines; article 2 of left palp with seven slender spines accompanied by five stiff setae; article 2 of right palp with six distal spines accompanied by five setae, and three setae on outer margin. Maxilla 2 ( Fig. 5K View Fig ): inner plate with a diagonal row of 18 plumose setae on inner face. Maxilliped ( Fig. 5H View Fig ): inner plate with one subapical spine and three apical spines; outer plate with a row of spines and several pectinate setae.
Coxal plates 1-3 subrectangular ( Figs. 6 View Fig A-C), with short setae on lower margins, coxal plates 2-3 with three to five setae on posterior margins; coxal plate 4 ( Fig. 6D View Fig )excavated on posterior margin, with two setae on anterior corner and eight setae on posterior margin; anterior lobe of coxal plate 5 ( Fig. 7A View Fig ) with one seta, posterior lobe with four stiff setae on lower margin; coxal plate 6 ( Fig. 7B View Fig ) with two setae on anterior margin and four stiff setae on posterodistal corner; coxal plate 7 ( Fig. 7C View Fig ) with four long setae on anterior margin and six short setae on posterior margin. Coxal gills 2-7 ( Figs. 7 View Fig K-P), accessory lobes of respective gills 2-4 subequal to each other in length; anterior lobe of gill five longer than posterior lobe.
Gnathopod 1 ( Figs. 6A, E View Fig ): basis with long setae on anteroproximal and posterior margins; palm of propodus with eight and 11 peg spines on inner and outer margins, respectively; dactylus with one seta on outer margin. Gnathopod 2 ( Figs. 6B, F View Fig ): basis similar to that of gnathopod 1; palm of propodus with eight and nine peg-shaped spines on inner and outer margins, respectively; dactylus with one seta on outer margin.
Pereopod 3 ( Figs. 6C, G View Fig ): basis with long setae on posterior margin; merus to propodus with groups of spines on posterior margins; dactylus with one plumose seta on outer margin and two setae at hinge of nail. Pereopod 4 ( Figs. 6D, H View Fig ): the armature of pereopod 4 similar to that of pereopod 3.
Pereopod 6 longer than pereopods 5 and 7 ( Figs. 7 View Fig A-F). Posterior margin of basis weakly sinuated in pereopod 5, expanded in pereopod 7, bearing a row of 18 short setae; inner face of bases of pereopods 6 and 7 with two posterodistal spines; merus to propodus with clusters of spines on anterior margins; dactyli slender, with one plumose seta on outer margin.
Pleonites 1-3 ( Fig. 5B View Fig ): posterodorsal margins with four, ten and four marginal setules, respectively. Epimeral plates weakly acuminated posteriorly, with a setule on posterodistal corner. Plate 1 ( Fig. 7G View Fig ) with 16 setae on anteroventral corner; plate 2 ( Fig. 7H View Fig ) with four submarginal spines and two marginal spines; plate 3 ( Fig. 7I View Fig ) with six spines on anterior ventral margin. Pleopods 1-3 subequal ( Figs. 8 View Fig A-C), peduncles with many setae on outer margins; both rami armed with plumose setae.
Urosomites without humps ( Fig. 5C View Fig ), urosomite 1 dorsomarginally with two clusters of four spines, urosomite 2 with one-two-one-one spines, urosomite 3 with one pair of lateral spines and two pairs of medial setae. Uropod 1 ( Fig. 8D View Fig ): peduncle with marginal spines and one basofacial spine; inner ramus with three spines on inner margin; outer ramus with one spine and two spines on outer and inner margins, respectively. Uropod 2 ( Fig. 8E View Fig ): peduncle with four and three spines on outer and inner margins, respectively; inner ramus with three spines and one spine on inner and outer margins, respectively; outer ramus shorter than inner ramus, with one spine on each side. Uropod 3 ( Fig. 8F View Fig ): peduncle with eight distal spines; inner ramus less than one-third of outer ramus in length, with two marginal spines and one distal spine; outer ramus lanceolate, with four groups of spines on outer margin, inner margin with five spine clusters and some plumose setae, terminal article about one-sixth times as long as proximal article.
Telson deeply cleft ( Fig. 7J View Fig ), longer than maximum basal width, bearing distal and distolateral spines.
Etymology. – The species is named for the type locality, Hebei Province.
Variation. – Pednucular article 1 of antenna 1 with one posterodistal spine in 21% specimens, and with posterodistal setae in 79% specimens. Mandibular palp article 1 with two distal spines in 42% specimens, and with three distal spines in 58% specimens.
Remarks. – Jesogammarus (J.) hebeiensis , new species, is very closely related with J. (J.) fontanus , new species, in: (1) peduncular article 1 of antenna 1 without distal spine, (2) spinose palp article 1 of mandible, and (3) outer ramus of uropod 2 with marginal spines. J. (J.) hebeiensis differs from J. (J.) fontanus by (1) inner lobes of lower lip distinct, (2) bases of pereopods 5-7 with more setae on posterior margin, and (3) inner ramus of uropod 3 about one-third of outer ramus in length, outer ramus lanceolate, and inner margin of outer ramus with four to six plumose setae (inner ramus about one-fourth of outer ramus, outer ramus foliaceous, and inner margin of outer ramus with about 10 plumose setae in fontanus ).
Jesogammarus (J.) hebeiensis is similar to J. (J.) fujinoi Tomikawa & Morino, 2003 in (1) the distinct inner lobe of lower lip, (2) the armature of epimeral plates 1-3, and (3) pleonites 1-3 without dorsal spine. J. (J.) hebeiensis differs from the latter by (1) peduncular article 1 of antenna 1 without distal spines (one spine in fujinoi ), (2) mandibular palp article 1 with two to three distal spines (unarmed in fujinoi ), (3) outer ramus of uropod 2 with marginal spines (marginally bare in fujinoi ), and (4) telson longer than maximum basal width (shorter than basal maximum width).
Jesogammarus (J.) fontanus and J. (J.) hebeiensis seem to compose a spinopalpus cluster with two Japanese species: J. (J.) spinopalpus Morino, 1985 and J. (J.) hinumensis Morino, 1993 in sharing spines on mandibular palp article 1, setose pleonites, sexually dimorphic setation in pereopods 5-7 (not confirmed in hebeieneis), and elongate telson. The further study of relationship among these four species is necessary.
Habitat. – This new species occurs in Lake Baiyangdian, about 100 km south of Beijing. Lake Baiyangdian consists of 141 small lakes, covers 366 square kilometers and is thought to be the largest freshwater lake in North China. Lake Baiyangdian was dried several times in the last 15 years because of too much reservoirs in up streams. Attempt to collect female specimens of current species are failed for two times.
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