Species: hydroides SPIEKMAN, NEENAN, FRASER, FERNANDEZ, RIEPPEL, NOSOTTI & SCHEYER, 2020
Etymology: Hydra refering to the long-necked mythical sea monster of Greek mythology, and Greek, -oides, "related to or resembling."
Note: Large individuals of Tanystropheus longobardicus.

Holotype: PIMUZ T2790

Locality: Monte San Giorgio on the border of Switzerland (Canton Ticino) and Italy (Lombardy).

Horizon: Besano Formation.

Biostratigraphy: Grenzbitumen zone.

Age: Anisian /Ladinian Stage, Mid Triassic Epoch, Middle Triassic.

Material: Skull and caudal vertebrae.

Referred material:

MSNM V 3663: Fragmentary skull of a juvenile.

PIMUZ T183 (examplar v of WILD, 1973): Skull and skeleton.

PIMUZ T2787 (examplar i of WILD, 1973): Skull and skeleton.

PIMUZ T2793 (examplar c of WILD, 1973): Skull and skeleton.

PIMUZ T2818 (examplar m of WILD, 1973): Skull and skeleton.

PIMUZ T2819 (examplar q of WILD, 1973): Skeleton.

SNSB-BSPG 1953 XV 2:

Skull after Wild, 1973

New interperatation of skull.

= Tanystropheus cf. T. longobardicus RIEPPEL, JIANG, FRASER, HAO, MOTANI, SUN & SUN, 2010

Note: The authors refer this specimen to the largest Tanystropheus longobardicus specimens which have been given a new species name and is here moved to that species.

Locality: Heshangsi of Nimaigu Village, Wusha District, Xingyi City, Guizhou Province, China.

Horizon: Zhuganpo Member, Falang Formation.

Biostratigraphy:

Age: Latest Ladinian Stage, Lower Mid Triassic Epoch, Middle Triassic.

Material:

GMPKU-P-1537: Nearly complete skeleton lacking the skull and first few cervical vertebrae.