Fig 1.
Phylogeny of the Gobioidei according to Betancur et al. [11], Nelson et al. [1], and Thacker [6].
6brG = gobioid families with six branchiostegal rays, 5brG = gobioid families with five branchiostegal rays. Modified after Gierl and Reichenbacher [12].
Fig 2.
Map of the area with the type localities (stars) of †Pirkenius diatomaceus and †P. radoni and other fossiliferous sites (F).
All sites are located in the České Středohoří Mountains (northern Czech Republic). Redrawn from Gaudant [19] under a CC BY license, with permission from Naturhistorisches Museum Wien, original copyright 2009.
Table 1.
Technical details of the micro-CTs of extant gobioids.
Table 2.
Morphological characters for classification of Gobioidei.
Fig 3.
Anatomical position and details of the palatine (yellow) of extant gobioid species.
(A) Eleotris pisonis (ZSM 9393), skull in lateral (A1) and dorsal (A2) views, left palatine (A3) in lateral view. (B) Gobius incognitus (NMP6V 146150), skull in lateral (B1) and dorsal (B2) views, left palatine (B3) in lateral view. All images based on μ-CT scanning. Abbreviations: ethm, ethmoid; ethm pr pal, ethmoid process of palatine; mx, maxilla; mxl pr pal, maxillary process of palatine; pal, palatine; pmx, premaxilla.
Fig 4.
Anatomical position and details of the palatine, the ceratohyal bone, and the branchiostegal rays of Rhyacichthys guilberti.
(A) MNHN 2019-0113-1, (A1) skull, (A2) left palatine, (A3) left ceratohyal with only five branchiostegal rays, (A4) right ceratohyal with six branchiostegal rays (all lateral view). (B) MNHN 2019-0113-2, (B1) skull, (B2) left palatine, (B3, B4) left ceratohyal in lateral (B3) and medial view (B4), each with six branchiostegal rays. All images based on μ-CT scanning. All scale bars 1 mm.
Fig 5.
Anatomical position and details of the palatine, the ceratohyal bone, and the branchiostegal rays of extant gobioid species.
(A) Protogobius attiti (MNHN 2019–0112), (A1) skull, (A2) left palatine, (A3, A4) left ceratohyal with six branchiostegal rays in lateral (A3) and medial (A4) view. (B) Perccottus glenii (UWFC 44788), (B1) skull, (B2) left palatine, (B3) left ceratohyal (bone only partially preserved) with six branchiostegal rays. (C) Eleotris pisonis (ZSM 9393), (C1) skull, (C2) left palatine, (C3) left ceratohyal with six branchiostegal rays. (D) Gobius incognitus (NMP6V 146150), (D1) skull, (D2) left palatine, (D3) left ceratohyal with five branchiostegal rays. All images based on μ-CT scanning, all images show lateral view except A4 (medial view). All scale bars 1 mm.
Fig 6.
Fossil skeletons of †Pirskenius diatomaceus Obrhelová, 1961.
(A) Specimen Pv 11669, skull (ventrolateral view) and anteriormost portion of the body (lateral view) exhibiting seven branchiostegal rays. (B) Specimen Pv 11672, complete skeleton with slightly disarticulated skull. (C) Specimen Pv 11671, skeleton with well-preserved dorsal fins, anal fin and caudal peduncle. (D) Specimen PC 2799, almost complete skeleton.
Fig 7.
Details of the head and jaw bones of †Pirskenius diatomaceus Obrhelová, 1961.
(A, B) Photo and reconstruction of specimen Pv 11669 (ventrolateral view) exposing bones of right (r) and left (l) side, with palatine (pal), ectopterygoid (ect) and entopterygoid (ent) preserved in anatomical connection. Upper arrow indicates ethmoid process of palatine, lower arrow points to ventral tip of palatine. Further abbreviations: aa, angulo-articular; ce, ceratohyal; den, dentary; fr, frontal; mx, maxilla; pmx, premaxilla; psph, parasphenoid; qu, quadrate; sy, symplectic; vo, vomer.
Fig 8.
Details of the branchiostegal rays and opercular bones of †Pirskenius diatomaceus Obrhelová, 1961.
(A, B) Photo and reconstruction of specimen PC 2786 showing branchiostegal rays (br) 1–6 articulating with anterior ceratohyal (ce (a)), and expanded branchiostegal ray 7 associated to posterior ceratohyal (ce (p)). Further abbreviations: bh, basihyal; cl, cleithrum; hm, hyomandibular; mx, maxilla; op, opercle; pop, preopercle; sop, subopercle; sy, symplectic.
Fig 9.
Fossil skeletons of †Pirskenius diatomaceus Obrhelová, 1961 showing details of fins.
(A) Specimen PC 2772 exhibiting dorsal and anal fins (posterior part not preserved). (B) Counterpart of (A) (PC 2773) displaying radials (r1–r4) and remains of the pectoral fin (pect) and first dorsal fin with D1 pterygiophore formula 3(122110) (pterygiophores indicated by arrows). (C1–3) Specimen PC 2791, overview (C1), close-up of caudal fin with well-preserved procurrent rays (C2), close-up of separated pelvic fins (C3). Further abbreviation: ptt, posttemporal.
Table 3.
Morphometric data of †Pirskenius diatomaceus.
Table 4.
Meristic data of †Pirskenius diatomaceus.
Table 5.
Comparison of morphometric data (in % of SL) and meristic counts between the two species of †Pirskenius.
Fig 10.
Two possible phylogenetic positions of the †Pirskeniidae based on mapping of morphological characters on a recently published molecular tree of extant Gobioidei.
(A) †Pirskeniidae is sister to all extant gobioid families except Rhyacichthyidae and Odontobutidae. (B) †Pirskeniidae is sister to Thalasseleotrididae + Gobiidae + Oxudercidae. Synapomorphies or autapomorphies are indicated with pink bars, convergently derived character states are shown in light blue, multistate characters are followed by a slash (/) after which the character state is indicated. For character numbers see Table 2. Tree adapted from Thacker et al. [7] 'based on DNA sequences of ten nuclear protein coding genes with a taxon sampling expanded from Near et al. [62]'.
Fig 11.
Phylogenetic position of the †Pirskeniidae based on maximum-parsimony analysis of 20 phylogenetically informative morphological characters.
(A) 50% majority rule consensus tree based on 20 most parsimonious trees inferred with PAUP*; matrix includes intra-family variation of characters 11 and 18 (see Table 2 for details). (B) 50% majority rule consensus tree based on 14 most parsimonious trees inferred with PAUP*; matrix excludes intra-family variation of characters 11 and 18. For both trees, tree length = 32 steps, CI = 0.906, RI = 0.914. Numbers in boxes are synapomorphies (respectively autapomorphies) as indicated by PAUP*; synapomorphies are the same for both trees. Numbers at nodes are bootstrap percentages from 1000 pseudoreplicates.