Research Article |
Corresponding author: Chaowei Zhou ( zcwlzq666@163.com ) Academic editor: Tihomir Stefanov
© 2024 Lingzhen Li, Chaoyang Li, Weihan Shao, Suxing Fu, Chaowei Zhou.
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:
Li L, Li C, Shao W, Fu S, Zhou C (2024) Two new species of freshwater goby (Teleostei, Gobiidae) from the Upper Youshui River, Chongqing, China. ZooKeys 1210: 173-195. https://doi.org/10.3897/zookeys.1210.128121
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Two previously unknown species of Rhinogobius have been discovered in the streams of the Upper Youshui River, within the Yuan River Basin, Xiushan County, Chongqing, China. These new species are named as Rhinogobius sudoccidentalis and Rhinogobius lithopolychroma. Phylogenetic analysis based on mitochondrial genomes revealed that R. sudoccidentalis is genetically closest to R. reticulatus, while R. lithopolychroma shares the greatest genetic similarity with R. leavelli. Morphological distinctions allow for the clear differentiation of these species. Rhinogobius sudoccidentalis sp. nov. is characterized by having VI–VII rays in the first dorsal fin and I, 8–9 rays in the second dorsal fin. The longitudinal scale series typically consists of 22–24 scales, while the transverse scale series comprises 7–8 scales. Notably, the predorsal scale series is absent and the total vertebrae count is 12+17=29. Rhinogobius lithopolychroma sp. nov. can be distinguished from other species by the presence of 13–15 rays on the pectoral fin. Its longitudinal scale series ranges from 30 to 33 scales, with no scales in the predorsal area. The total vertebral count is 30, with 12 precaudal and 18 caudal vertebrae. The head and body of this species are light gray with irregular orange markings on the cheeks and opercle. Through morphological and molecular analyses, it has been confirmed that R. lithopolychroma and R. sudoccidentalis represent novel species within the Rhinogobius genus.
China, fish taxonomy, Gobiidae, Gobionellinae, mitochondrial genome, Yuanjiang River Basin
The genus Rhinogobius, belonging to the subfamily Gobionellinae within the family Gobiidae, is widely distributed across East and Southeast Asia. First described by Gill in 1859, with Rhinogobius similis Gill, 1859 as the type species, this genus is known for its high species richness. Over 92 valid species have been described, with an increasing number of new species being discovered. In recent years, several new species of Rhinogobius have been found in China, including R. houheensis Kunyuan et al., 2020, R. coccinella Endruweit, 2018, R. maculagenys
The Upper Yuanjiang River Basin benefits from a favorable climate and encompasses numerous stream habitats within its mountainous areas. The biodiversity in Xuan’en and Fanjingshan, traversed by the Upper Yuanjiang River Basin, is exceptionally high and potentially serves as a glacial refuge (
During surveys conducted between June 2023 and January 2024 in the streams of the Upper Youshui River within the Yuanjiang River Basin in Chongqing, two species of Rhinogobius were discovered. Historically, only R. similis and Rhinogobius cliffordpopei (Nichols, 1925) were documented in the Yuanjiang River Basin in Chongqing, with these species primarily adapted to lake and reservoir environments (
A total of 44 specimens were collected from Chongqing Municipality and Guizhou Province (Fig.
Morphological measurements were primarily based on a previous study (
Four specimens were used for DNA barcoding. Total DNA was extracted from the caudal fin following
List of accession numbers and sequence length of mitochondrial genome sequences in this study.
Accession number | Length of sequence (bp) | Remarks | |
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Rhinogobius estrellae | LC648292 | 16682 |
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Rhinogobius estrellae | LC648294 | 16504 |
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Rhinogobius estrellae | LC648295 | 16505 |
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Rhinogobius estrellae | LC648296 | 16504 |
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Rhinogobius tandikan | LC648297 | 16691 |
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Rhinogobius tandikan | LC648298 | 16690 |
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Rhinogobius tandikan | LC648299 | 16918 |
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Rhinogobius tandikan | LC648300 | 16690 |
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Rhinogobius similis | LC648303 | 16499 |
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Rhinogobius similis | LC648304 | 16499 |
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Rhinogobius formosanus | MT363639 | 16500 |
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Rhinogobius formosanus | MN549279 | 16502 | Genbank |
Rhinogobius szechuanensis | OM617727 | 16492 | Liu WZ et al. (2023) |
Rhinogobius leavelli | MH729000 | 16499 |
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Rhinogobius davidi | OM617724 | 16627 |
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Rhinogobius rubromaculatus | KU674802 | 16503 | Genbank |
Rhinogobius flumineus | LC648305 | 16504 |
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Rhinogobius flumineus | LC648306 | 16503 |
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Rhinogobius yaima | LC648307 | 16500 |
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Rhinogobius yaima | LC648308 | 16500 |
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Rhinogobius yonezawai | LC648309 | 16500 |
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Rhinogobius yonezawai | LC648310 | 16500 |
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Rhinogobius nagoyae | LC648315 | 16498 |
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Rhinogobius sp. MO | LC648314 | 16499 |
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Rhinogobius brunneus | LC648311 | 16500 |
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Rhinogobius brunneus | LC648312 | 16500 |
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Rhinogobius wuyiensis | OM678441 | 16502 | Chen XJ et al. (2022b) |
Rhinogobius lentiginis | OM617725 | 16633 | Chen XJ et al. (2022b) |
Rhinogobius niger | OM791349 | 16496 | Genbank |
Rhinogobius maculagenys | OK545540 | 16500 | Hu J et al. (2023) |
Rhinogobius shennongensis | OM961050 | 16500 | Genbank |
Rhinogobius cliffordpopei | KX898434 | 16511 | Genbank |
Rhinogobius cliffordpopei | KP694000 | 16529 | Genbank |
Rhinogobius cliffordpopei | KT357638 | 16525 | Genbank |
Rhinogobius duospilus | MH127918 | 16496 |
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Rhinogobius filamentosus | OM678440 | 16510 | Chen XJ et al. (2022b) |
Rhinogobius wuyanlingensis | OM617722 | 16491 |
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Rhinogobius wuyanlingensis | OM961051 | 16491 | Genbank |
Rhinogobius sp. Xiushan | SRR28284919 | 16486 | Collected in Xiushan, Chongqing |
Rhinogobius lithopolychroma | SRR28284920 | 16493 | Collected in Xiushan, Chongqing |
Rhinogobius sudoccidentalis | SRR28284918 | 16480 | Collected in Xiushan, Chongqing |
Rhinogobius reticulatus | SRR28284917 | 16497 | Collected in Fuzhou, Fujian Province |
Tridentiger kuroiwae | LC653489 | 16501 |
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Tridentiger kuroiwae | LC653490 | 16501 |
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Holotype. China • 1 ♂; Chongqing City, Xiushan County; 28°23'23"N, 108°53'16"E; 1 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230001.
Paratypes. China - Chongqing City • 7 ♂♂, 3 ♀♀; Xiushan County; 28°23'23"N, 108°53'16"E; 1 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230101 to 20230110. • 4 ♂♂ ; Xiushan County; 28°26'17"N, 108°59'12"E; 1 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230111 to 20230114. • 1 ♂ , 1 ♀ ; Xiushan County; 28°24'51"N, 109°7'13"E ; 3 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230115, 20230116. • 1 ♂ , 2 ♀♀ ; Xiushan County; 28°22'30"N, 108°53'18"E; 4 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230118, 20230120. - Guizhou Province • 1 ♂ ; Tongren City; 28°8'50"N, 108°59'13"E; 3 July. 2023; Lingzhen Li & Chaoyang Li leg.; RS20230117.
Rhinogobius sudoccidentalis can be distinguished from other species in the genus by the following characteristics: it possesses VI–VII rays in the first dorsal fin and I, 8–9 rays in the second dorsal fin. The longitudinal scale series typically consists of 22–24 scales (most commonly 23), while the transverse scale series typically comprises 7–8 scales (most commonly 8). The predorsal scale series is absent. The total number of vertebrae counts is 12+17=29. Additionally, it features a black line stripe beneath the eye that extends to the mandible. Morphometrics Reference Table
Morphometrics of the types of R. sudoccidentalis expressed as a percentage of standard length.
Variable | Holotype | Paratypes | |
---|---|---|---|
Sex | males | males (N = 14) | Females (N = 6) |
Morphometry | |||
Standard length (mm) | 33.1 | 33.1–40.6(36.5) | 30.2–36.5(32.1) |
Head length (mm) | 8.9 | 8.9–11.5(10.3) | 7.3–9.9(8.1) |
Percent standard length (%) | |||
Head length | 26.9 | 26.5–30.3(28.4) | 23.7–27.1(25.2) |
Predorsal length | 37.8 | 31.7–43.1(37.4) | 34.5–39.0(36.9) |
Snout to second dorsal fin origin | 53.8 | 53.6–59.2(56.2) | 57.1–59.4(58.4) |
Snout to anal fin origin | 59.5 | 55.4–64.9(58.9) | 59.3–64.7(62.7) |
Snout to anus | 54.1 | 51.2–56.9(53.5) | 50.5–59.0(56.0) |
Pre pelvic length | 28.7 | 28.7–35.7(31.3) | 28.8–33.7(30.6) |
Caudal peduncle length | 26.9 | 21.8–29.2(25.7) | 17.3–27.5(23.2) |
Caudal peduncle depth | 8.8 | 8.2–10.5(9.2) | 8.0–11.9(9.5) |
First dorsal-fin base | 8.5 | 8.5–17.3(12.8) | 8.6–13.5(11.2) |
Second dorsal-fin base | 16.3 | 13.1–19.9(16.9) | 14.6–19.6(16.1) |
anal fin base | 14.2 | 8.5–14.3(11.7) | 8.7–11.7(10.0) |
Caudal fin length | 20.8 | 18.4–26.1(22.1) | 13.5–23.8(18.5) |
Pectoral fin length | 20.2 | 19.6–24.1(21.8) | 16.6–21.0(18.7) |
Pelvic fin length | 14.5 | 13.5–19.2(15.7) | 12.5–18.1(15.8) |
Body depth of pelvic fin origin | 9.1 | 9.1–14.2(11.5) | 9.8–12.9(11.7) |
Body depth of anal fin origin | 9.4 | 8.3–13.0(10.4) | 9.3–11.5(10.6) |
Pelvic fin origin to anus | 26.9 | 22.0–27.2(25.2) | 25.6–30.8(27.4) |
Head depth | 9.7 | 9.7–12.2(11.0) | 9.6–12.9(11.0) |
Percent head length (%) | |||
Snout length | 31.5 | 22.8–37.4(30.6) | 19.2–31.6(25.5) |
Eye diameter | 14.6 | 11.3–19.3(14.2) | 10.4–16.5(12.0) |
Cheek depth | 56.2 | 20.7–32.2(25.5) | 21.2–29.1(24.1) |
Postorbital length | 55.1 | 43.1–60.4(51.7) | 49.5–58.9(54.4) |
Lower jaw length | 31.5 | 27.9–48.7(38.7) | 24.2–37.7(31.0) |
Interorbital width | 22.5 | 11.9–24.0(20.8) | 12.1–19.5(16.3) |
Head width in maximum | 51.7 | 45.5–61.7(52.7) | 50.5–65.8(58.0) |
Fins : The fins display distinct features: the first dorsal fin typically bears VI rays (18) or VII rays (2), while the second dorsal fin exhibits either I, 8 rays (2) or I, 9 rays (18). The 3rd or 4th spine of the first dorsal fin is the longest and lacks filamentous. In males, the depressed first dorsal fin extends to the base of the 1st or 2nd branched ray of the second dorsal fin; in females, it reaches only the base of the second dorsal fin anteriorly. The anal fin has I, 6 rays (1) or I, 7 rays (19), originating at a vertical line between the 2nd and 3rd branched soft ray of the second dorsal fin. The pectoral fin typically has 14 rays (2) or 15 rays (18) and is broad. In males, the rear tip of the pectoral fin aligns parallel to the anus, a feature absent in females.
Scales : The body is covered with ctenoid scales, with enlarged mid-trunk scales. The anterior predorsal area lacks scales, while the posterior occipital region is adorned with cycloid scales. The belly is covered with small cycloid scales. The longitudinal scale series ranges from 22 to 24 (mode: 23), and the transverse scale series ranges from 7 to 8 (mode: 8). No scales are present in the predorsal area.
Head canals : Pores σ are located between the anterior and posterior nares. The anterior interorbital sections of oculoscapular canal are separated, featuring paired pore λ. A single pore κ is situated in the posterior region, with ω present near posterior edge of eyes. There is an absence of ω1. The lateral section of anterior oculoscapular canal exhibits pores α and terminal pore ρ. The posterior oculoscapular canal ends with two terminal pores θ and τ. Preopercular canals are presented, featuring pores ε, γ, and δ.
Sensory papillae : Row a extends anteriorly to just before the middle of the eye. Row b is oblique and reaches forward to the posterior margin of the eyes. Rows c and d are longer, extending behind the orbit, with Row cp positioned between Rows c and d. Row f is paired. Opercular papillae include Rows ot, oi, and os, with oi nearly reaching ot.
Vertebrae : The total vertebrae count is 12 + 17 = 29 (N = 5), with a (P–V) pattern of 3/II II I I 0/9 (N = 5).
Coloration of preserved specimens : In males, the head and body of R. sudoccidentalis exhibit a yellowish-brown color. There are paired brown stripes on the snout converging at the tip, while the cheeks and opercle are adorned with small black spots. A black stripe extends from under the eye to the mandible. The ventral side displays dens coverage of small black spots. The membrane of the first dorsal fin is gray, the second dorsal fin has a transparent membrane with dense black mottling, and the anal fin exhibits a black membrane. The pectoral fin is transparent. In females, the head and body are yellowish, with a single black diagonal line below each eye. Irregular black patches are present on the ventral side, and both the dorsal and anal fins are transparent.
Color in life : In males, the head and body of the R. sudoccidentalis are creamy white. There are paired reddish-brown stripes on the snout meeting at the tip, and the cheeks and opercle feature small black spots. A black stripe extends from under the eye to the mandible. The ventral side is densely covered with small orange spots. The membrane of the first dorsal fin is red with a blue mottling pattern between the 1st and 2nd spinous rays. The second dorsal fin has a transparent membrane with dense black mottling and a white outer edge. The anal fin exhibits a white margin with reddish dots on the ventral part of the reddish membrane. The pectoral fin is transparent, with a milky white basal portion. In females, the head and body are yellowish, with paired brown stripes on the snout meeting at the tip. There are single black diagonal lines below the eyes, and irregular black patches on the ventral side. Both the dorsal and anal fin are transparent, and the pectoral fin is transparent with a milky white basal portio.
Rhinogobius sudoccidentalis was initially discovered in a small stream in Xiushan, Chongqing, where it predominantly inhabits areas characterized by large cobblestone substrates and slow-flowing water at depths ranging from approximately 30 to 50 cm. Additionally, small populations of this species were also observed in Tongren, Guizhou Province. In the Xiushan area, R. sudoccidentalis is the dominant fish species, utilizing the cobblestone bottom as an egg deposition site, with eggs characterized as large (size 1.6–2.1 mm). During periods of high water levels in the creek, individuals aggregate near the shore to seek refuge from the rapids.
This species, discovered in Chongqing and Guizhou Province in the southwestern region of China, has been named R. sudoccidentalis. The Latin roots “sud” meaning “south” and “occidentalis” meaning “western” combine to signify “southwestern”. The suggested Chinese name for this species is 西南吻虾虎鱼.
Holotype. China • 1 ♂; Chongqing City, Xiushan County; 28°21'21"N, 108°52'16"E; 2 July. 2023; Lingzhen Li & Chaoyang Li leg.; RL20230001.
Paratypes. China • Chongqing City • 6 ♂♂, 4 ♀♀; Xiushan County; 28°21'21"N, 108°52'16"E; 2 July. 2023; Lingzhen Li & Chaoyang Li leg.; RL20230101 to 20230110. • 11 ♂♂, 1 ♀; Xiushan County; 28°19'56"N, 108°52'17"E; 4 July. 2023; Lingzhen Li & Chaoyang Li leg.; RL20230111 to 20230122.
Rhinogobius lithopolychroma can be distinguished from other species in the Rhinogobius by the following characteristics: It typically possesses 13–15 rays on the pectoral fin. The longitudinal scale series count ranges from 30 to 33, with the predorsal area lacking scales. The total vertebrae count is 30, comprising 12 precaudal and 18 caudal vertebrae. The head and body of this species are light gray, adorned with irregular orange markings on the cheeks and opercle. Morphometrics Reference Table
Morphometrics of the types of R. lithopolychroma expressed as a percentage of standard length.
Variable | Holotype | Paratypes | |
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Sex | males | males (N = 17) | Females (N = 5) |
Morphometry | |||
Standard length (mm) | 28.2 | 28.2–38.8(31.1) | 27.5–36.4(33.6) |
Head length (mm) | 9.5 | 7.9–11.6(9.6) | 7.9–10.7(9.7) |
Percent standard length (%) | |||
Head length | 33.7 | 25.8–33.7(28.9) | 25.8–30.3(28.8) |
Predorsal length | 36.5 | 28.2–43.4(37.2) | 32.4–41.6(37.1) |
Snout to second dorsal fin origin | 58.2 | 42.0–58.5(54.6) | 54.2–62.0(58.9) |
Snout to anal fin origin | 66.7 | 56.7–66.7(61.8) | 63.5–66.9(65.1) |
Snout to anus | 56.4 | 51.5–57.2(55.2) | 55.6–61.2(58.5) |
Pre pelvic length | 31.9 | 26.2–34.8(30.5) | 28.3–34.9(31.6) |
Caudal peduncle length | 18.8 | 18.8–23.1(21.1) | 18.4–24.1(21.4) |
Caudal peduncle depth | 10.6 | 9.0–12.2(10.6) | 9.5–11.4(10.6) |
First dorsal-fin base | 13.5 | 10.3–15.2(13.0) | 9.9–14.2(11.9) |
Second dorsal-fin base | 22.3 | 16.1–22.8(19.1) | 14.5–21.2(16.6) |
anal fin base | 15.2 | 10.8–15.8(13.8) | 10.4–15.7(12.2) |
Caudal fin length | 28.0 | 15.4–28.0(22.7) | 17.8–23.4(20.3) |
Pectoral fin length | 25.5 | 19.3–26.7(22.4) | 20.5–21.2(21.0) |
Pelvic fin length | 11.7 | 9.6–13.8(11.3) | 9.9–12.7(11.5) |
Body depth of pelvic fin origin | 11.3 | 9.2–16.3(13.2) | 12.0–15.6(14.0) |
Body depth of anal fin origin | 9.6 | 9.2–14.6(12.0) | 11.3–15.4(12.9) |
Pelvic fin origin to anus | 25.5 | 19.3–25.9(22.9) | 20.3–26.9(23.5) |
Head depth | 12.1 | 10.1–13.8(12.4) | 11.3–14.2(13.4) |
Percent head length (%) | |||
Snout length | 21.1 | 19.4–30.1(24.6) | 15.2–28.6(20.3) |
Eye diameter | 15.8 | 11.4–19.5(14.9) | 13.1–21.5(17.1) |
Cheek depth | 23.2 | 15.2–28.4(24.1) | 17.7–25.5(22.2) |
Postorbital length | 42.1 | 41.7–54.0(45.7) | 45.7–58.2(49.3) |
Lower jaw length | 26.3 | 18.8–37.0(29.6) | 15.3–25.5(22.7) |
Interorbital width | 33.7 | 25.9–39.3(32.4) | 26.6–31.6(28.7) |
Head width in maximum | 49.5 | 43.3–65.5(54.9) | 48.6–64.9(56.5) |
Fins : The fin configuration includes 6 rays on the first dorsal fin (VI), with a 22 total rays. The second dorsal fin consists of one spine and either 9 or 10 branched rays, totaling 15 rays. The fourth or fifth spine of the first dorsal fin is the longest and non-filamentous. In males, when the first dorsal fin is depressed, the rear tip extends to the base of the second branched ray of the second dorsal fin, while in females it reaches only to the base of the second dorsal fin anteriorly. The anal fin has 1 spine and either 7 or 8 branched rays, totaling 13 rays. The origin of the anal fin is inserted at a vertical line between the first and second branched soft ray of the second dorsal fin. The pectoral fins range from 13 to 15 rays, with 13 rays most common (present in 8 specimens), 14 rays in 13 specimens, and 15 in 1 specimen. The pectoral fins are broad in shape.
Scales : The body covered with ctenoid scales, with enlarged mid-trunk scales. The anterior predorsal area lacks scales, while the posterior part of the occipital region is covered by cycloid scales. The belly is adorned with small cycloid scales. The longitudinal scale series count ranges from 30 to 33, with a mode of 31. The transverse scale series count ranges from 7 to 9, with a mode of 8.
Head canals : pores σ are located parallel to the anterior nares. The anterior interorbital sections of the oculoscapular canal are separated, featuring paired pore λ. There is a single pore κ in the posterior region, with ω present near posterior edge of eyes and a lack of ω1. The lateral section of anterior oculoscapular canal includes pores α and a terminal pore ρ. The posterior oculoscapular canal possesses two terminal pores θ and τ. Preopercular canals are presented, with pores ε, γ, and δ.
Sensory papillae : The sensory papillae arrangement is as follows: Row a extends to before the middle of the eye. Row b is oblique and reaches forward to the orbit. Rows c and d extend to the posterior margin of the eyes, and Row cp is absent. Row f is paired. In the opercular region, there are rows ot, oi, and os. Rows oi and ot are not connected.
Vertebrae : The total vertebrae count is 12 + 18 = 30 (N = 5) and (P–V) 3/II II I I 0/9 (N = 5).
Coloration of preserved specimens : In males, the head and body are gray with irregular markings on the cheeks and operculum. The ventral side is densely covered with tiny black spots and has six large, sometimes inconspicuous, horizontal black lines. The first dorsal fin is yellowish, While the second dorsal fin is yellowish-brown. The anal fin is yellowish. Females exhibit a gray head and body, with the first dorsal fin being yellowish and displaying blue spots between the 1st and 2nd spiny rays. The second dorsal fin is yellowish-brown, and the anal fin is yellowish.
Colour in life : Males display a light gray head and body with irregular orange markings on the cheeks and operculum, along with three smaller orange lines along the eyes. The ventral side is densely covered with tiny orange spots and has six large, sometimes inconspicuous, horizontal black lines. The first dorsal fin shows orange outlines on spines IV – VII with a white outer edge and blue spots between the 1st and 2nd spiny rays. The second dorsal fin is orange with irregular blue markings internally and on the outer edge, as well as blue spots on the 1st and 2nd spiny rays and a wide white margin. The anal fin is orange at the base, transitioning to black with a wide white margin. Females also exhibit a light gray head and body with irregular orange markings on the cheeks and operculum, and three smaller orange lines along the eyes. The ventral side is densely covered with tiny orange spots and features six large horizontal black lines. The first dorsal fin displays orange outlines on spines IV–VII with a yellow outer edge and blue spots between the 1st and 2nd spiny rays. The second dorsal fin is orange, and the anal fin is orange at the base, transitioning to black with a wide white margin.
Rhinogobius lithopolychroma is restricted to fast-flowing, shallow streams with a cobble substrate in Xiushan, Chongqing. The surveyed streams ranged from 10 to 30 cm in depth. This goby species is characterized by its large eggs (1.5–2.1 mm in size), which it deposits on the bottom surface of the cobblestones.
Rhinogobius lithopolychroma was discovered in a small stream with a colorful cobble substrate. Accordingly, we named this species after its habitat. In Ancient Greek, “litho” means “stone,” and “polychroma” means rich in color. We combined these two words to christen this species. We suggest the Chinese name of this species as “彩石吻虾虎鱼”.
Rhinogobius sudoccidentalis and R. lithopolychroma are found in close geographical proximity and share some environmental commonalities, yet their morphology differs considerably. Rhinogobius sudoccidentalis typically features a longitudinal scale series of 30–33, while R. lithopolychroma exhibits 22–24 scales. In body coloration, R. sudoccidentalis appears creamy white with black spots on the cheeks and operculum, and a densely spotted ventral side. Conversely, R. lithopolychroma is light gray with irregular orange markings on the cheeks and operculum, and a ventral side densely covered with tiny orange spots, often accompanied by six large, occasionally inconspicuous, horizontal lines of black.
Morphologically, R. sudoccidentalis bears the closest resemblance to Rhinogobius reticulatus Li, Zhong & Wu, 2007 (Fig.
As depicted in the phylogenetic tree, R. lithopolychroma is closest to Rhinogobius leavelli (Herre, 1935) and Rhinogobius davidi (Sauvage & Dabry de Thiersant, 1874), whereas R. sudoccidentalis is closest to Rhinogobius filamentosus (Wu, 1939), R. wuyanlingensis, R. reticulatus and Rhinogobius duospilus (Herre, 1935) (Fig.
Morphological comparison of Rhinogobius lithopolychroma with the genetically closest species.
Variable | R. lithopolychroma | R. leavelli | R. davidi |
---|---|---|---|
1st dorsal fin | VI | VI | VI |
2nd dorsal fin | I 9-10 | I 8-9 | I 9-10 |
Anal fin | I 7-8 | I 8-9 | I 6-8 |
Pectoral fin | 13-15 | 14-15 | 14-15 |
Longitudinal scale | 30-33 | 28-34 | 30-32 |
Transverse scale | 7-9 | 9-11 | 11-12 |
Predorsal scale | 0 | 6-12 | 0-4 |
Total vertebrae | 30 | 26 | 28 |
References | This study |
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Morphological comparison of Rhinogobius sudoccidentalis with the genetically closest species.
Variable | R. sudoccidentalis | R. filamentosus | R. wuyanlingensis | R. reticulatus | R. duospilus |
---|---|---|---|---|---|
1st dorsal fin | VI–VII | V–VI | V–VI | VI | VI |
2nd dorsal fin | I 8-9 | I 8-9 | I 8-9 | I 8-9 | I 8-9 |
Anal fin | I 6-7 | I 8 | I 8 | I 7-8 | I 6-7 |
Pectoral fin | 14-15 | 15-17 | 17-18 | 15-17 | 15-16 |
Longitudinal scale | 22-24 | 30-33 | 30-32 | 27-29 | 30-32 |
Transverse scale | 7-8 | 8-10 | 9-10 | 8-9 | 8-10 |
Predorsal scale | 0 | 5-11 | 7-9 | 3-6 | 6-10 |
Total vertebrae | 29 | 27 | 27 | 26-27 | 27 |
References | This study |
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According to studies by
In the Upper Youshui River catchment, previously documented Rhinogobius species include R. similis and R. cliffordpopei, known to favor lakes, reservoirs, and stagnant water environments. Conversely, the new species discovered in this study exclusively inhabit streams. These newly identified species are all classified as large-egg types, indicating their better adaptation to stream habitats compared to the small-egg types like R. similis and R. cliffordpopei (
Presently, the survival of the two recently discovered Rhinogobius species faces certain threats. For instance, manganese ore collection in the headwaters of streams where R. sudoccidentalis resides may have significant implications for the species survival. Additionally, R. lithopolychroma is restricted to a narrow habitat and is only found in alpine streams, underscoring the importance of prioritizing its protection and conducting further detailed studies on its biology and ecology.
We thank Mr Wang from Chongqing and Mr Wu from Yunnan for their help in sample collection. Thanks to Mr Zhi and Mr Luo for providing the photos. Thanks to Mr Wang of CAS for providing the filming and scanning equipment. Thank you to Mr Shao and Mr Zhou for their extensive revisions of the paper.
The authors have declared that no competing interests exist.
No ethical statement was reported.
National Talent Research Grant for 2023 (No. 5330500953);Natural Science Foundation of Chongqing (Grant No. CSTB2022NSCQ-MSX0566).
Lingzhen Li: methodology, formal analysis, validation, writing-original draft, writing-review, editing, investigation. Chaoyang Li: methodology, investigation, formal analysis, formal analysis. Weihan Shao: data curation, project administration, resources, supervision, writing-review and editing. Suxing Fu: data curation, project administration, resources, supervision, writing-review and editing. Chaowei Zhou: data curation, project administration, resources, supervision, writing-review and editing.
Lingzhen Li https://orcid.org/0009-0008-2139-4009
Suxing Fu https://orcid.org/0009-0001-0562-1469
All of the data that support the findings of this study are available in the main text.