Rhinolepadichthys, Fujiwara & Motomura & Summers & Conway, 2024
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publication ID |
https://dx.doi.org/10.3897/vz.74.e113955 |
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publication LSID |
lsid:zoobank.org:pub:C920DCB5-053D-4DD6-8892-3BA74E65C092 |
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persistent identifier |
https://treatment.plazi.org/id/C3BDA09B-3C4E-4689-A5EE-31C3233C0749 |
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taxon LSID |
lsid:zoobank.org:act:C3BDA09B-3C4E-4689-A5EE-31C3233C0749 |
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treatment provided by |
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scientific name |
Rhinolepadichthys |
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gen. nov. |
Rhinolepadichthys gen. nov.
Type species.
Lepadichthys polyastrous Fujiwara & Motomura, 2021
Diagnosis.
A new genus of the Gobiesocidae belonging to the Diademichthyinae and distinguished from all other genera by having a row of 8-12 large papillae on the inner surface of the upper and lower lips (Fig. 3C, F View Figure 3 ).
The following characters are also diagnostic, although not unique to the new genus (details discussed in "Relationships of Rhinolepadichthys gen. nov. and Discotrema " [see below]): snout tip well extended, distinctly beyond tip of lower jaw (Fig. 3B, E View Figure 3 ); upper lip fused with skin of snout, therefore usually lacking a distinct groove between lip margin and snout, but if present, groove very weak, restricted to posterior portion of upper jaw only (Fig. 3A, B, D, E View Figure 3 ); anterior part of lower lip without skin lobes and fused with skin of gular area (Fig. 3C, F View Figure 3 ); absence of well-developed lateral process on pterotic immediately posterior to exit of otic canal (Figs 4A, B View Figure 4 , 5A, B View Figure 5 , 6 View Figure 6 ); upper-jaw teeth only weakly hooked, with tip of crown blunt or rounded (Figs 4B View Figure 4 , 5B View Figure 5 , 7A, D View Figure 7 ); medial edge of premaxilla very weakly concave, forming indistinct, narrow oval opening anteriorly in dorsal view between premaxillae (Figs 4A View Figure 4 , 5A View Figure 5 ); gill membrane attached to isthmus; upper pharyngeal teeth arranged in a loose patch on ventral surface of pharyngobranchial 3 toothplate, with tooth tips directed posteroventrally (Figs 4C View Figure 4 , 5C View Figure 5 , 7F, G View Figure 7 ); two rows and single row of gill rakers on ceratobranchials 1-3 and 4, respectively (Fig. 7E View Figure 7 ); ceratobranchial 5 edentulous (Fig. 7E, H View Figure 7 ); preopercle without lateral-line canal and associated pores (PR1-3) (Fig. 3 View Figure 3 ); single adhesive disc (Fig. 8A View Figure 8 ); absence of a deep cavity at center of disc region C (Fig. 8A View Figure 8 ); absence of three paired and one median cluster of small papillae across disc surface (Fig. 8A View Figure 8 ); disc papillae with a roughly hexagonal or ovoid outline and flattened surface, some larger papillae with a hardened (potentially keratinized) cap (Fig. 8A View Figure 8 ); anterolateral part of ventral postcleithrum extended anteriorly as a well-developed rod-like process, its tip close to base of pelvic-fin soft ray 4 (Figs 4C View Figure 4 , 5C View Figure 5 , 8B View Figure 8 ); and ventral postcleithrum entire, not divided into two separate, articulating elements (Figs 4C View Figure 4 , 5C View Figure 5 , 8B View Figure 8 ).
Description.
See Fujiwara and Motomura (2021: 63: "Common features of the L. lineatus complex") for information on external morphology. Photographs and line drawing of heads, showing cephalic lateral-line canal pores plus snout and lip characters, given in Fig. 3 View Figure 3 . Features of osteology shown in Figs 4 View Figure 4 - 9 View Figure 9 . Neurocranium comprising nasal, lateral ethmoid, mesethmoid, sphenotic, pterotic, epiotic, prootic, supraoccipital, basioccipital, exoccipital, frontal, vomer, parasphenoid, and parietal (Fig. 6 View Figure 6 ). Nasal slender, its anterior tip slightly rounded, not reaching to anterior edge of premaxillae in dorsal view (Figs 4A View Figure 4 , 5A View Figure 5 ); its posterior tip articulating with anterior part of frontal. Sphenotic with sharply pointed lateral process just below exit of supraorbital canal. Exit of otic canal forming robustly pointed lateral process on pterotic. Vomer generally T-shape, its anteriormost point slightly protracted, its posterior tip well pointed, reaching to slightly before epiphyseal commissure of supraorbital canal in ventral view. Parasphenoid narrowest anteriorly, expanded posteriorly, forming an oval shape posteriorly. Infraorbital series comprising lachrymal only, firmly attached to tip of short and slender cartilage extending from anterolateral tip of lateral ethmoid (Fig. 6 View Figure 6 ).
Viscerocranium of C&S specimen shown in Fig. 7 View Figure 7 . Jaws comprising premaxilla, maxilla, dentary, anguloarticular, and retroarticular (Fig. 7A-D View Figure 7 ). Premaxilla with 8 or 9 dorsoventrally elongated (roughly rectangular shape) incisiviform teeth with weakly hooked distal tip, forming angle of ca. 45° (Fig. 7A, D View Figure 7 ; also see Conway et al. 2015: fig. 11B, H, I); teeth on anterior part of premaxilla distinctly larger than those of posterior part; ventrally directed process with rounded tip present on posteroventral tip of premaxilla. Dentary with 8 or 9 similarly sized incisiviform teeth, similar in shape to those on premaxilla; anterior 4 or 5 teeth somewhat more elongate, with tip weakly curved and directed upward, remaining teeth with hooked distal edge but usually poorly defined as a result of abrasion (Fig. 7B, C View Figure 7 ; also see Conway et al. 2015: fig. 11B, J); posteromedial face of dentary with squarish process. Anguloarticular without foramen (see Springer and Fraser 1976: fig. 3b); anterior quarter pointed, inserted into medial face of dentary; posterior part with well-developed dorsal process (termed coronoid process by Fujiwara et al. 2021), its tip rounded and directed anterolaterally. Hyopalatine arch comprising autopalatine, quadrate, hyomandibular, ectopterygoid, and symplectic (Fig. 7A View Figure 7 ). Hyomandibular generally squarish; posterodorsal part with posterior process; antero- and posteroventrally directed processes present, latter process distinctly larger than former. Ectopterygoid large, triangular, its dorsal tip approaching posteroventral tip of autopalatine. Opercular bones comprising opercle, subopercle, preopercle, and interopercle (Fig. 7A View Figure 7 ). All bones poorly ossified, excluding articular head of opercle. Subopercle without spine-like posterior tip. Gill arches comprising basihyal, 4 paired epibranchials, paired pharyngobranchial 3 and associated toothplate, 3 paired hypobranchials, 5 paired ceratobranchials, and 3 basibranchial cartilages (Fig. 7E-H View Figure 7 ). Basihyal long, slender, its anterior tip cartilaginous. Pharyngobranchial 3 toothplate squarish with two poorly defined rows of ca. 5 conical teeth on ventral surface; teeth of outer row larger than those of inner row (Fig. 7F, G View Figure 7 ). Row of small triangular gill rakers present on anterior and posterior edges of ceratobranchials 1-3, and anterior edge of ceratobranchial 4; row on anterior edge of ceratobranchial 1 short, comprising ca. 2-3 gill rakers; other rows with ca. 5-7 gill rakers (Fig. 7E View Figure 7 ). Ceratobranchial 5 lanceolate, edentulous (Fig. 7H View Figure 7 ). Hyoid bar comprising dorsal hypohyal, anterior and posterior ceratohyals, interhyal, and 6 slender branchiostegal rays (Fig. 7I View Figure 7 ). Posterior half of urohyal well forked in lateral view.
Pelvic- and pectoral-fin girdles and caudal skeleton of C&S specimen shown in Fig. 8 View Figure 8 and Fig. 9A View Figure 9 , respectively. Pelvic-fin girdle comprising basipterygium, and dorsal postcleithrum, and ventral postcleithrum. Pectoral-fin girdle with posttemporal, supracleithrum, cleithrum, scapula, coracoid, and 4 pectoral radials (Fig. 8 View Figure 8 ). Anterior outline of basipterygia together triangular, posterior outline resembles inverted T-shape. Dorsal postcleithrum roughly triangular, with well-developed fimbriae along posterior edge. Ventral postcleithrum irregular in shape; posterolateral margin weakly serrated; posterior margin concave, with well-developed fimbriae. Complex articulation present between posterior tip of basipterygium and anteromedial edge of ventral postcleithrum. Caudal skeleton comprising upper and lower hypural plates, epural, and parhypural cartilage (Fig. 9A View Figure 9 ). Hypural plates separated by narrow diastema.
Based on Rhinolepadichthys polyastrous (SAIAB 9319), total number of vertebrae 33 or 34, including 17 or 18 abdominal and 16 caudal vertebrae. Ribs 13 or 14, associated with vertebrae 3-15 or 3-16. Epicentrals 20, associated with vertebrae 2-21. First dorsal-fin pterygiophore inserted between neural spines of vertebrae 19/20. First anal-fin pterygiophore inserted between hemal spines of vertebrae 21/22.
Included species.
The genus contains the following four valid species, previously included in the " Lepadichthys " Lepadichthys lineatus complex by Fujiwara and Motomura (2021): Rhinolepadichthys geminus (Fujiwara and Motomura, 2021) comb. nov., Rhinolepadichthys heemstraorum (Fujiwara and Motomura, 2021) comb. nov., Rhinolepadichthys lineatus (Briggs, 1966) comb. nov., and Rhinolepadichthys polyastrous (Fujiwara and Motomura, 2021) comb. nov.
Etymology.
The suffix rhino -, meaning nose, in combination with Lepadichthys , a genus of the Diademichthyinae . In reference to the pointed snout in members of this genus, which distinguishes the new genus from Lepadichthys (sensu stricto). Gender masculine.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.