Mordellidae

The Mordellidae are a family of beetles commonly known as tumbling flower beetles for the typical irregular movements they make when escaping predators, or as pintail beetles due to their abdominal tip which aids them in performing these tumbling movements. Worldwide, there are about 1500 species.

Anatomy
The apparent tumbling movements are composed of a series of very rapid separate jumps (each jump of a duration of approximately 80 ms). They result from the beetle's efforts to get itself back into take-off position for flight when it has been in either a lateral or dorsal position. Each individual jump should be considered an extended rotation, performed by one leg of the third leg pair (metapodium). Depending on whether the left or the right metapodium is used as the leg that provides the leverage for take-off, change occurs in the direction of the jump. The energy for propulsion varies with the beetle's immediate muscle work, so that jump lengths and heights vary, with rotation frequencies recorded up to 48 per second (Mordellochroa abdominalis)  around the gravitation centre of the body's longitudinal axis. Additional revolving around the transverse axis (at lower frequency) effects spiralling somersaults that are perceived as tumbling. While the pintail (pygidium) is of no significance for the jump, the meta-trochanter-femur (thighs and surrounding rings of the third leg pair) has a great capacity for free rotation (up to 270 degrees, at one level only). This capacity is due to a screw joint that connects the base of the metacoxa to the head of trochanter. The nut gradient is 21 degrees. Technically similar jumps, though less powerful, can be observed in the families Melandryidae (=Serropalpidae) (genus Orchesia) and Scraptiidae (genus Anaspis). Their coxa-trochanter-joints are of similar structure. It is inferred that the capacity of a tumbling form of locomotion is rooted in a common phylogeny and can therefore not be ascribed specifically to Mordellidae. Other authors have pointed out the speciality of the screw joint. Weevils of the genus Trigonopterus, in the Asian tropical rainforest, for example, have an even tighter connective construction in the coxa-trochanter joint than is found in Mordellidae. This construction, however, does not facilitate an equally high angular velocity of the torque. The joint here serves to provide a better grip on plants and easier climbing.

Systematics


This family has two living subfamilies – Mordellinae and Ctenidiinae – and a prehistoric one known only from fossils (Praemordellinae). Another fossil genus, Liaoximordella, was previously treated as distinct monotypic family Liaoximordellidae, but is now regarded as very primitive and probably basal member of the Mordellidae.

Subfamily Ctenidiinae Franciscolo, 1951 Subfamily Mordellinae Latreille, 1802
 * Ctenidia Laporte de Castelnau in Brullé, 1840
 * †Angimordella Bao et al. 2019 Burmese amber, Myanmar, Cenomanian
 * Tribe Conaliini Ermisch, 1956
 * Conalia Mulsant & Rey, 1858
 * Conaliamorpha Ermisch, 1968
 * Glipodes LeConte, 1862
 * Isotrilophus Liljeblad, 1945
 * Ophthalmoconalia Ermisch, 1968
 * Paraconalia Ermisch, 1968
 * Pseudoconalia Ermisch, 1950
 * Stenoconalia Ermisch, 1967
 * Xanthoconalia Franciscolo, 1942
 * Tribe Mordellini Siedlitz, 1875
 * Adelptes Franciscolo, 1965
 * †Asiamordella Hong, 2002 Fushun amber, China, Ypresian
 * Austromordella Ermisch, 1950
 * Binaghia Franciscolo, 1943
 * Boatia Franciscolo, 1985
 * Caffromorda Franciscolo, 1952
 * Calycina Blair, 1922
 * Cephaloglipa Franciscolo, 1952
 * Congomorda Ermisch, 1955
 * Cothurus Champion, 1891
 * Curtimorda Méquignon, 1946
 * Glipa LeConte, 1859
 * Glipidiomorpha Franciscolo, 1952
 * Hoshihananomia Kônô, 1935
 * Iberomorda Méquignon, 1946
 * Ideorhipistena Franciscolo, 2000
 * Klapperichimorda Ermisch, 1968
 * Larinomorda Ermisch, 1968
 * Machairophora Franciscolo, 1943
 * Macrotomoxia Píc, 1922
 * Mordella Linnaeus, 1758
 * Mordellina Schilsky, 1908
 * Mordellapygium Ray, 1930
 * Mordellaria Ermisch, 1950
 * Mordelloides Ray, 1939
 * Mordellopalpus Franciscolo, 1955
 * Neocurtimorda Franciscolo, 1950
 * Neotomoxia Ermisch, 1950
 * Ophthalmoglipa Franciscolo, 1952
 * Paramordella Píc, 1936
 * Paramordellana Ermisch, 1968
 * Paramordellaria Ermisch, 1968
 * Paraphungia Ermisch, 1969
 * Parastenomordella Ermisch, 1950
 * Paratomoxia Ermisch, 1950
 * Paratomoxioda Ermisch, 1954
 * Phungia Píc, 1922
 * Plesitomoxia Ermisch, 1955
 * Praemordella Shchegoleva-Barovskaya, 1929
 * Pseudomordellaria Ermisch, 1950
 * Pseudotomoxia Ermisch, 1950
 * Sphaeromorda Franciscolo, 1950
 * Stenaliamorda Ermisch & Chûjô, 1968
 * Stenomorda Ermisch, 1950
 * Stenomordella Ermisch, 1941
 * Stenomordellaria Ermisch, 1950
 * Stenomordellariodes Ermisch, 1954
 * †Succimorda Kubisz, 2001 Baltic amber, Eocene
 * Tolidomordella Ermisch, 1950
 * Tolidomoxia Ermisch, 1950
 * Tomoxia Costa, 1854
 * Tomoxioda Ermisch, 1950
 * Trichotomoxia Franciscolo, 1950
 * Variimorda Méquignon, 1946
 * Wittmerimorda Franciscolo, 1952
 * Yakuhananomia Kônô, 1935
 * Zeamordella Broun, 1886
 * Tribe Mordellistenini Ermisch, 1941
 * Asiatolida Shiyake, 2000
 * Calyce Champion, 1891
 * Calycemorda Ermisch, 1969
 * Calyceoidea Ermisch, 1969
 * Dellamora Normand, 1916
 * Diversimorda Ermisch, 1969
 * Ermischiella Franciscolo, 1950
 * Fahraeusiella Ermisch, 1953
 * Falsomordellina Nomura, 1966
 * Falsomordellistena Ermisch, 1941
 * Falsopseudomoxia Franciscolo, 1965
 * Glipostena Ermisch, 1941
 * Glipostenoda Ermisch, 1950
 * Gymnostena Franciscolo, 1950
 * Mordellina Schilsky, 1908
 * Mordellistena Costa, 1854
 * Mordellistenalia Ermisch, 1958
 * Mordellistenochroa Horák, 1982
 * Mordellistenoda Ermisch, 1941
 * Mordellistenula Stchegoleva-Barowskaja, 1930
 * Mordellochroa Emery, 1876
 * Mordellochroidea Ermisch, 1969
 * Mordelloxena Franciscolo, 1950
 * Morphomordellochroa Ermisch, 1969
 * Neomordellistena Ermisch, 1950
 * Palmorda Ermisch, 1969
 * Palpomorda Ermisch, 1969
 * Paramordellistena Ermisch, 1950
 * Phunginus Píc, 1922
 * Pselaphokentron Franciscolo, 1955
 * Pseudodellamora Ermisch, 1942
 * Pseudotolida Ermisch, 1950
 * Raymordella Franciscolo, 1956
 * Tolida Mulsant, 1856
 * Tolidopalpus Ermisch, 1951
 * Tolidostena Ermisch, 1942
 * Uhligia Horák, 1990
 * Xanthomorda Ermisch, 1968
 * Tribe Reynoldsiellini Franciscolo, 1957
 * Reynoldsiella Ray, 1930
 * Tribe Stenaliini Franciscolo, 1956
 * Brodskyella Horák, 1989
 * Pselaphostena Franciscolo, 1950
 * Stenalia Mulsant, 1856
 * Stenaliodes Franciscolo, 1956
 * †Subfamily Praemordellinae Shchegoleva-Barovskaya 1929
 * †Bellimordella Liu et al. 2008 Yixian Formation, China, Aptian
 * †Cretanaspis Huang and Yang 1999 Lushangfen Formation, China, Aptian
 * †Mirimordella Liu et al. 2007 Yixian Formation, China, Aptian
 * †Praemordella Shchegoleva-Barovskaya 1929 Karabastau Formation, Kazakhstan, Oxfordian
 * †Wuhua Wang and Zhang 2011 Daohugou, China, Callovian