Rhinogobius coccinella, Endruweit, 2018

Endruweit, Marco, 2018, Description of four new species of freshwater gobies from the Black River drainage in China and Vietnam (Teleostei: Gobiidae), Zootaxa 4486 (3), pp. 284-310 : 286-293

Rhinogobius coccinella , new species

( Figs. 1–3 )

Holotype. ZFMK ICH-104092 , 41.8 mm SL, male; Chahe village , Jiangcheng Cty., Puer Pref., Yunnan Prov., China; Mengyejiang River; coll. M. Endruweit, 28 Dec. 2011 .

Paratypes. ZFMK ICH-104093 , 1 specimen, 40.9 mm SL, data as for holotype . ZFMK ICH-104099, 4100, 2, 36.5–42.4 mm SL, location and collector as for holotype, 30 Dec. 2011. KIZ 2008001975-1985, 11, 36.1–46.3 mm SL; Jiangcheng Cty., Puer Pref., Yunnan Prov., China; Labuhe River , Mengyejiang River; coll. J. Yang et al., 27 April 2008 .

Diagnosis. Rhinogobius coccinella can be distinguished from its congeners by the following combination of characters: cheek and operculum with about 25 dark spots, notably larger than the pupil, and branchiostegal membrane unmarked; dark chevron-shaped mark on snout; caudal-peduncle depth 11–12% SL; 1–5 [3] predorsal scales; 27–30 [29] scales in midlateral series; 9–10 [9] transverse scales; and 28 vertebrae.

Description. Morphometric proportions given in Table 2. Caudal peduncle short and moderately shallow; depth 2.1–2.4 in length in males, 2.1–2.5 in females. Head short, slightly depressed, wider than deep. Eye small, dorsolateral. Interorbital distance moderate. Cheek not inflated; edge of operculum represents maximum body width. Snout rounded. Mouth terminal, oblique, about 40° to body axis in males, about 30° in females. Lips thick, fleshy in males, thin in females. Maxilla extends past a vertical through anterior rim of orbit in males, almost reaching anterior rim in females. Jaws equal, each with 4–5 alternating rows of small villiform teeth; outer 2 rows slightly enlarged, recurved. Gill opening small, dorsally not reaching upper origin of pectoral fin, ventrally almost reaching forward to isthmus. Gill rakers 4 + 7. Genital papilla short, not reaching origin of anal fin. VC 11 + 17 = 28; AP 2–3 [3]; DF 3-22110. Largest known size 47.1 mm SL (KIZ 2008001957, male).

Fins. D 1 VI; D 2 I,8–9 [8]; A I,7–8 [7]; P 15–17 [16]; C 7 + 7. First dorsal fin spines III or IV longest, nonfilamentous, not reaching origin of second dorsal fin when adpressed. Second dorsal fin and anal fin not reaching midway to caudal-fin base, reaching fin base in large males of about 45 mm SL.

Scales. LL 27–30 [29]; TR 9–10 [9]; PD 1–5 [3]; SDP 6–9 [8]; CPS 12. Flank scales arranged in regular rows; anterior margin of predorsal squamation concave, laterally reaching forward to about pore Θ, medianly with small cycloid scales anterior to first dorsal fin ( Fig. 3 ); anterior margin of abdominal squamation obliquely bridging space between bases of pectoral and pelvic fins. Head, nape, prepectoral, pre- and subpelvic areas naked. Scales along the abdominal midline small, cycloid.

Cephalic lateralis system. Canals: Preorbital section of anterior oculoscapular canal with terminal pore σ between nostrils, mesially; pore λ and central pore κ located at about a vertical through anterior rim of orbit and posterior rim, respectively; postorbital section of oculoscapular canal with pore ω located dorsolaterally, slightly posterior to vertical through pore α; pores α and ρ located laterally in oculoscapular groove. Posterior oculoscapular canal with terminal pores Θ and τ. Terminal pores ρ and Θ separated by distance of about 1/5 eye diameter. Preopercular canal with pores γ, δ and ε along edge of preoperculum. Sensory papillae: Row a long with about 6 papillae slanting downward anteriorly, reaching past vertical through mid of orbit. Row b short, with about 12 papillae, straight and slightly slanting downward posteriorly. Row c long, from beneath anterior nostril to vertical through posterior rim of orbit with about 11 prominent papillae. Row d long, with about 25 papillae, running along labial groove to about posterior rim of orbit. Rows c and d nearly diverging. Row cp as single papilla located between the terminals of rows c and d. Opercular rows os, ot and oi present; ot and oi not interconnected. Approximate pathways of canals and papillae rows depicted in Figure 3 .

Coloration of preserved specimens. Head and body beige, gradually darker dorsally. Flank with 6–7 blotches of diffuse dark brown spots along midline; spots as large as pupil. Dorsum with 4–6 inconspicuous beige saddles. Scales in longitudinal series variable, either plain beige or beige with dark brown mark along distal edge. Nape gray. Snout with dark brown chevron-shaped mark. Cheek and operculum with about 25 dark brown spots; spots larger than pupil in males; spots smaller than pupil and partially coalescent forming vermiform lines in females. Branchiostegal membrane gray and unmarked. Pectoral fin with 3 dark brown spots along base, upper spot always conspicuous, lower two spots inconspicuous in some specimens. First dorsal fin with conspicuous black blotch anterior to spine II followed by a broad gray band between spines II and V in males, 3–4 transverse rows of gray spots in females. Second dorsal fin with 6–7 transverse rows of gray spots and a broad white distal band. Caudal fin with 7–8 transverse rows of gray spots. Pectoral gray to hyaline. Pelvic fin gray with brown median band. Anal fin beige with broad dark brown median band and broad white distal band in males, median band less conspicuous in females.

Distribution. Mengyejiang River in Jiangcheng County located in the western corner of Puer Prefecture, Yunnan Province, China ( Fig. 4 ).

Etymology. Named after a genus of ladybugs. The large dark spots on the cheek and operculum in males of Rhinogobius coccinella allude to the elytron coloration of some ladybug species; a noun in apposition.

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Rhinogobius coccinella sp. nov. Rhinogobius nanophyllum sp. nov. holotype paratypes holotype paratypes male males (n = 6) females (n = 6) male males (n = 9) females (n = 6) range mean range mean range mean range mean

Standard length (mm) 41.8 41.8 – 45.7 36.5 – 46.3 58.1 52.9 – 59.4 42.7 – 46.3

In percents of SL

Lateral head length 29.2 29.2 – 31.1 30.1 26.8 – 27.7 27.3 28.7 28.2 – 31.8 29.5 26.9 – 28.1 27.7

Predorsal length (D1) 37.3 36.2 – 37.3 36.8 35.6 – 37.4 36.2 38.7 37.6 – 39.4 38.8 36.8 – 38.2 37.6

Preanal length 61.2 58.7 – 61.2 60.3 61.4 – 64.7 63.4 59.7 57.5 – 61.9 59.2 59.0 – 65.6 61.7

Pre-anus length 56.7 56.6 – 58.3 57.3 57.0 – 60.7 58.6 55.6 53.3 – 56.9 54.7 52.9 – 61.6 57.4

Head depth (eye) 14.1 13.8 – 15.3 14.5 11.8 – 14.2 12.9 17.2 14.0 – 18.6 16.3 15.0 – 15.5 15.3

Head depth (nape) 14.6 14.0 – 16.0 15.2 15.1 – 16.2 15.7 18.1 14.7 – 19.7 17.3 16.4 – 18.3 17.4

Body depth (D1 origin) 17.5 16.8 – 17.9 17.4 18.7 – 21.0 19.7 19.8 17.8 – 22.0 19.8 20.9 – 24.8 22.5

Body width (D1 origin) 17.0 16.6 – 18.1 17.4 17.0 – 21.6 18.8 17.9 16.6 – 21.4 18.8 20.2 – 21.3 20.6

Body width (A origin) 14.1 11.8 – 14.1 12.9 12.9 – 14.4 13.5 15.5 13.6 – 16.3 15.2 15.6 – 16.4 15.9

Caudal-peduncle depth 11.0 10.9 – 12.1 11.3 10.8 – 12.2 11.3 11.4 10.4 – 12.2 11.4 11.2 – 11.9 11.5

Caudal-peduncle length 25.1 25.1 – 26.3 25.6 25.9 – 27.1 26.5 22.0 22.0 – 24.9 23.9 23.1 – 25.8 24.6

Snout length 9.6 9.0 – 10.2 9.6 7.9 – 8.8 8.4 9.3 8.1 – 10.5 9.4 6.7 – 8.0 7.3

Head width (mid of eye) 17.2 16.7 – 19.3 17.9 12.7 – 15.2 13.9 16.4 16.2 – 17.3 16.5 16.2 – 16.6 16.4

Maximum head width 21.5 20.9 – 23.1 22.0 19.7 – 20.3 19.9 24.4 21.2 – 24.4 23.1 21.6 – 23.7 22.4

Head width (tip of operculum) 14.8 14.6 – 15.8 14.9 14.3 – 15.4 14.8 16.4 16.2 – 17.3 16.5 16.2 – 16.6 16.4

D1 base length 15.8 14.6 – 16.9 15.6 14.0 – 16.2 15.0 16.2 11.7 – 16.2 14.5 13.0 – 14.1 13.5

D2 base length 17.5 16.1 – 18.1 17.3 14.8 – 17.3 16.4 19.8 18.1 – 20.1 19.1 18.4 – 19.1 18.8

A base length 14.8 12.6 – 14.8 13.9 10.8 – 13.0 12.1 18.1 14.7 – 18.1 16.0 12.1 – 14.8 13.7

Pectoral-fin length 23.4 22.5 – 25.8 24.0 21.7 – 23.3 22.4 21.2 21.2 – 24.2 22.7 22.2 – 25.8 23.7

Pelvic-fin length 16.5 16.1 – 17.2 16.7 16.8 – 17.6 17.3 15.7 14.3 – 17.2 16.2 16.6 – 19.0 17.5 ……continued on the next page

Snout length 32.8 31.0 – 32.8 32.0 29.6 – 31.9 30.7 32.3 28.7 – 34.6 31.8 23.8 – 28.3 26.3 Eye diameter 18.0 18.0 – 19.0 18.6 20.6 – 22.9 21.7 18.6 17.7 – 21.5 19.2 21.5 – 23.3 22.5 Interorbital width 7.4 7.1 – 10.9 9.0 8.0 – 11.6 9.9 6.6 6.1 – 9.2 7.4 4.2 – 5.8 4.9 Head width (tip of operculum) 50.8 47.5 – 50.8 49.5 52.4 – 55.8 54.3 56.9 52.5 – 57.7 56.1 57.5 – 60.8 59.2 Pectoral-fin length 80.3 76.6 – 83.1 79.7 79.3 – 84.2 82.1 73.7 73.7 – 79.6 76.8 79.2 – 91.7 85.6 Pelvic-fin length 56.6 54.8 – 56.6 55.6 61.9 – 65.3 63.2 54.5 47.8 – 61.1 55.0 60.0 – 67.5 63.1

Ratios

Eye diameter/interorbital width 1.2 1.2 – 1.6 1.3 1.3 – 1.4 1.3 1.6 1.3 – 1.6 1.5 1.2 – 1.5 1.3 Caudal-peduncle length/depth 2.3 2.1 – 2.4 2.3 2.1 – 2.5 2.3 1.9 1.9 – 2.4 2.1 1.9 – 2.2 2.1 Caudal-peduncle depth/length 0.4 0.4 – 0.5 0.4 0.4 – 0.5 0.4 0.5 0.4 – 0.5 0.5 0.4 – 0.5 0.5 Gape width/gape length 1.3 1.0 – 1.3 1.1 1.0 – 1.4 1.1 1.2 1.0 – 1.3 1.2 1.2 – 1.3 1.2 SL/HL 3.4 3.2 – 3.4 3.3 3.6 – 3.7 3.7 3.5 3.1 – 3.6 3.4 3.6 – 3.7 3.6 SL/body depth (D1 origin) 5.7 5.6 – 5.9 5.8 4.8 – 5.3 5.1 5.1 4.6 – 5.6 5.1 4.0 – 4.8 4.5 SL/caudal-peduncle length 4.0 3.8 – 4.0 3.9 3.7 – 3.9 3.8 4.5 4.0 – 4.5 4.2 3.9 – 4.3 4.1 SL/caudal-peduncle depth 9.1 8.3 – 9.2 8.9 8.2 – 9.3 8.8 8.8 8.2 – 9.6 8.8 8.4 – 8.9 8.7 HL/maximum head width 1.4 1.3 – 1.4 1.4 1.4 1.4 1.2 1.2 – 1.3 1.3 1.2 – 1.3 1.2 HL/snout length 3.1 3.0 – 3.2 3.1 3.1 – 3.4 3.3 3.1 2.9 – 3.5 3.2 3.5 – 4.2 3.8 HL/eye diameter 5.5 5.3 – 5.5 5.4 4.4 – 4.8 4.6 5.4 4.7 – 5.7 5.2 4.3 – 4.6 4.5 HL/interorbital width 13.6 9.1 – 14.0 11.5 8.6 – 12.6 10.3 15.2 10.9 – 16.5 13.7 17.1 – 24.0 20.9 HL/gape length 2.3 2.1 – 2.4 2.2 2.8 – 3.1 2.9 2.0 2.0 – 2.4 2.2 2.7 – 2.9 2.8

Figures

FIGURE 1. Rhinogobius coccinella, ZFMK ICH-104092, holotype, 41.8 mm SL, male; Jiangcheng, Yunnan, China; Mengyejiang River.

FIGURE 2. Rhinogobius coccinella, paratypes; Jiangcheng, Yunnan, China; Mengyejiang River; upper: ZFMK ICH-104099, 42.2 mm SL, male; lower: ZFMK ICH-104093, 40.9 mm SL, female.

FIGURE 3. Rhinogobius coccinella, cephalic lateralis system, composite drawing based on holotype and paratypes.

FIGURE 4. Map of the Red River and adjacent drainages. Rivers: 1, Mekong; 2, Ma River, 3, Black River; 4, Red River; 5, Nanpanjiang River. Type localities: Ǫ, Rhinogobius coccinella; ●, R. nanophyllum; □, R. ngutinhoceps; ■, R. phuongae.