Thrissops formosus Agassiz, 1833

Ebert, Martin, 2025, New species of the genus Thrissops (Teleostei, Ichthyodectiformes) in the Upper Jurassic of the Solnhofen-Archipelago (Germany) and Kimmeridge Clay (England), Zitteliana 99, pp. 1-32 : 1-32

publication ID	https://doi.org/10.3897/zitteliana.99.159055
publication LSID	lsid:zoobank.org:pub:56F0851A-2905-49A1-96CC-232BC6868976
DOI	https://doi.org/10.5281/zenodo.16422309
persistent identifier	https://treatment.plazi.org/id/A83CAB00-845B-584F-AE3A-65C6F3C1E438
treatment provided by	Zitteliana by Pensoft
scientific name	Thrissops formosus Agassiz, 1833
status

Treatment

Figs 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 18 A, B View Figure 18 , 20 B View Figure 20 , 21 View Figure 21

1833 Thrissops formosus Agassiz : Vol. II, pt. 1, p. 12.

1843 Thrissops formosus Agassiz : Vol. II, pt. 2, p. 124, 293.

1843 Thrissops formosus Agassiz : Atlas, Vol. II, pl. 65 a.

1852 Thrissops formosus Agassiz ; Quenstedt: p. 219, pl. 17, fig. 19.

1854 Thrissops Heckeli ; Thiollière: pl. 10, fig. 1.

1863 Thrissops formosus Agassiz ; Wagner: p. 734.

1887 Thrissops formosus Agassiz ; Zittel: p. 274, figs 280, 281.

1895 Thrissops formosus Agassiz ; Woodward: p. 521 (partim only NHMUK PV OR 49139, 35013, P. 913, P. 3683, P. 3684).

1914 a Thrissops formosus Agassiz ; Eastman: p. 387.

1914 b Thrissops formosus Agassiz ; Eastman: p. 423 (only CM 4702).

1949 Thrissops formosus Agassiz ; Saint-Seine: p. 268 (partim), pl. 26 A.

1958 Thrissops formosus Agassiz ; Nybelin: p. 447, textfig. 1.

1964 Thrissops formosus Agassiz ; Nybelin: p. 5–10, pl. 1, figs 1, 2; pl. 2, figs 1, 2.

1965 Thrissops formosus Agassiz ; Bardack: p. 33, fig. 13 F.

1977 Thrissops formosus Agassiz ; Taverne: figs 1, 2, 5, 6, 9–12, 14–16.

1977 Thrissops formosus Agassiz ; Patterson and Rosen: figs 12–14.

1984 Thrissops formosus Agassiz ; Schaeffer and Petterson: p. 41; figs 24 B, 26 C, 27 D, I.

1994 Thrissops formosus Agassiz ; Frickhinger: fig. 493.

1998 Thrissops formosus Agassiz ; Tischlinger: figs 3, 4; pls 1–3.

2008 Thrissops cf. formosus Agassiz ; Ebert and Kölbl-Ebert: fig. 11.

2010 a Thrissops cf. formosus Agassiz ; Ebert and Kölbl-Ebert: fig. 3.

2011 Thrissops cf. formosus Agassiz ; Ebert and Kölbl-Ebert: fig. 7.

2013 Thrissops formosus Agassiz ; Cavin et al.; p. 155–156.

2013 Thrissops cf. formosus Agassiz ; Ebert and Kölbl-Ebert: p. 44; figs 2 a, 2 b, 5; tab. 1.

2014 Thrissops formosus Agassiz ; Berrell et al.: figs 7 B, 8.

2015 Thrissops cf. formosus Agassiz ; Ebert et al.: p. 20, figs 8 a, b.

2018 Thrissops formosus Agassiz ; Yabumoto et al.: fig. 7, 8.

2019 Thrissops formosus Agassiz ; Cavin and Berrell: fig. 9.

2020 Thrissops formosus Agassiz ; Kölbl-Ebert and Ebert: fig. 15 a.

2021 Thrissops formosus Agassiz ; Ebert: p. 38; figs 6 a, 6 b; tabs 1, 2.

2024 Thrissops formosus Agassiz ; Alvarado-Ortega: fig. 16, tab. 2.

2024 Thrissops formosus Agassiz ; Ebert: p. 355; figs 12.10 A – C, 12.15, 13.8; tab. 12.1.

Holotype.

SNSB - BSPG AS VII 2 ( Ebert 2021, fig. 6 A) .

Type locality.

Kelheim (most probably Kapfelberg) , Bavaria, Germany.

Type horizon.

Upper Kimmeridgian.

Determination

(for measurements of specimens and counts of features see Suppl. material 1: table S 1). Maximum length 75 cm; 37–40 supraneurals; 57–61 vertebrae (without ural centra); 29–32 ribs anterior of anal fin; 28–31 (maximum at 30) anal pterygiophores; small teeth on all jaws (Figs 3 View Figure 3 , 18 A, B View Figure 18 ); dorsally curved hook at the anteriormost tip of the dentary with two small, posteriorly directed teeth (Figs 3 View Figure 3 , 18 A, B View Figure 18 ); curved maxilla (Figs 3 View Figure 3 , 18 A, B View Figure 18 , 20 B View Figure 20 ).

Additional material.

BMMS (Eichstätt without number); CAM SM F. 11220 (Kelheim); CM 4702 (Eichstätt or Solnhofen); CM 4083, 4091 (both Cerin); Coll. Tischlinger 88 / 91 (Eichstätt), 09 / 2, 92 / 2 (both Ettling); DMA (Painten without number); GPIT - PV- 42046, 50597 (both Kelheim); JME -ETT 46, 47, 73, 74 (Fig. 2 B View Figure 2 ), 75 (Fig. 2 A View Figure 2 ), 76, 87 a, b, 93, 103, 126, 139, 157, 209, 211, 245, 281, 283, 564, 869, 873, 879, 886, 887, 900 a, b, 972, 1350, 1357, 1595, 1799, 1805 a, b, 2076, 2079, 2166, 2171, 2550, 2750, 2872, 2941, 2942, 2966, 3108, 3109 a, b, 3111, 3205, 3208, 3340, 3341, 3344, 3355, 3371, 3379, 3471, 3473, 3476, 3630, 3657, 3680, 3685, 3686 (Fig. 2 C View Figure 2 ), 3909, 3914, 3917, 4094, 4108, 4315, 4379, 4413 (all Ettling); JME -SOS 2516 (Eichstätt), 4254 (Schernfeld), 7849 (Ettling); LF 1215 (Eichstätt), 2319 (Ettling); MB. f. 1375 (Kelheim), 1590 (? Solnhofen), 9756, 15864, 15874, 18259 (all Kelheim); MHNL 20015136, 20015137, 20015185, 20015188, 20015760, 20150031, 20150198, 20150525, 20150558, 20150799, 20150913, 20272030 (all Cerin); MMG-SNSD BaJ 2120 (Kelheim); MNHN SLN 2 (Kelheim), MNHN CRN 9, 73, 82 (all Cerin); NHMW 1852. II. 61 (Kelheim); NHMUK PV OR 35013 (Kelheim), P. 913, P. 913 B (both Kelheim), P. 917 (Solnhofen), P. 918 (Cerin), P. 3683, P. 3684 (both Kelheim); NMP UC 10, 103, 104 (all three Kelheim), NMS 1879.30. 5, 1882.32. 4 (both Kelheim); NMWIN 801821 counterpart 801822 (Kelheim); NRM P 00002924 (Solnhofen), PIMUZ A / I 0389 (Kelheim); SMNS - P- 86701 (Eichstätt); SNSB - BSPG AS VII 2 (holotype), AS VII 175 (both Kelheim), SNSB - BSPG 1997 XVIII 1514, 1515 (both from Brunn); TM 14842 (Cerin); UCBL -FSL 93382 , 502300, 503200 (all Cerin); YPM VPPU. 003282 (Eichstätt).

Distribution and frequency.

In the Upper Kimmeridgian and Lower Tithonian. Common in Ettling and Kelheim (both Solnhofen Archipelago, Bavaria, Germany) and Cerin (Ain, France); rare in the following localities of the Solnhofen Archipelago: Brunn, Eichstätt, Painten and Solnhofen (for localities and exact numbers see Fig. 1 View Figure 1 and Suppl. material 1: table S 1).

Features.

Due to space constraints, not all features of Th. formosus can be described in detail, as the new species described below have priority and features of Th. formosus have already been described before (see list of publications above). In this article, the features of Th. formosus are presented mainly in detailed photos and corresponding drawings of specimens from Ettling (for the cranium see Figs 3 A, B View Figure 3 , 4 A – D View Figure 4 , 18 A, B View Figure 18 , 20 B View Figure 20 and for the caudal fin and skeleton see Figs 5 A – C View Figure 5 , 21 View Figure 21 ).

Features not described before.

Thanks to the embedding of JME -ETT 3371 , it was possible for the first time to take a photo and a drawing of the skull of Th. formosus in dorsal view (Fig. 4 C, D View Figure 4 ). Particularly interesting in this specimen is the parietal in dorsal view, as it seems that the parietal bones of both sides have fused together to form a median bone.

At the anteriormost tip of the dentary, all specimens of Thrissops formosus have a dorsally curved hook that carries two posteriorly directed teeth which have nearly the same size as the other dentary teeth (see Figs 3 View Figure 3 , 18 A, B View Figure 18 and comparison to the other species in the discussion section below).

The caudal fin is deeply forked, but in some very well-preserved specimens ( JME -ETT 126 , 173, 283, 564, 887, 2750 (Fig. 21 A View Figure 21 ), 2941, 3111 (Fig. 5 C View Figure 5 ), 3340, 3473, 4108) an elongation of parts of the principal rays seven and eight is visible. The extension is in ray seven only on the ventral side and in ray eight on the dorsal side, so that together they form an inner caudal tip (Figs 2 C View Figure 2 , 5 C View Figure 5 ).

History.

The holotype of Thrissops formosus (SNSB - BSPG AS VII 2) and type specimen of the genus, which survived the bombing of WWII were stolen from a display case in Munich in 1975 and found again in 1979 in the collection of an invertebrate collector in Munich who claimed to have bought the piece at a flea market (see document in old catalogue of the BSPG).