Gambaryan's rodents

Petros Petrovich Gambaryan (18.IV.1925 – 31.VIII.2017) was the greatest myologist of mammals in Russia ever. He was an outstanding person. Brave hunter and field zoologist, he was as fast and active as open and kind. He hated the soviet regime and loved freedom and children. He used to gather all numerous offsprings of all his numerous relatives (he had four sisters and a younger brother Pavel, a botanist) to take care alone over all of them for summer vacations at a dacha. But his main passion was science, and his favorite exercise was muscle dissection.<br>Gambaryan was born in Paris, France, and returned with his family to Armenia in 1929, when he was four. When he was about ten, he came to Professor Semen Smirensky of the Zoo-Veterinarian Institute in Yerevan to study animal anatomy. Since then and up to his death, for the total of about 80 years, and starting his working day from early morning, he dissected muscles of all mammals whose specimens his hand could reach, including two Indian elephants. In 1958, Gambaryan moved from Yerevan to the Zoological Institute of Leningrad (St. Petersburg) wherein he was affiliated all the remaining career.<br>His first paper published in 1946 (https://arar.sci.am/dlibra/publication/27224/edition/24332) was about shoulder girdle muscles of rodents with an emphasis on burrowing adaptations of <i>Spalax</i>. Mammalian morphological adaptations to burrowing was his first topic which resulted in his first dissertation defended in 1949 and expanded to a book published in 1960. His second topic was mammalian morphological adaptations to running which resulted in his second dissertation defended in 1969 and published as a book in 1972 and, in English translation, in 1974. Studying burrowing and running, Gambaryan paid primary attention not only to quantitative research (weighing) of muscles, but also to filming the respective locomotor motions with rapid cinema camera, preferably in the field, immediately after capturing wild animals, and preferably when they burrow with maximal effort, run at maximal speed, and jump by maximal length. His third topic was the facial musculature of mammals which resulted in a book in 1989.<br>Having dissected animals for 80 years as a routine daily exercise, Gambaryan approached by the number of dissections those giants of the past, such as Cuvier, Owen and Fürbringer. However, Gambaryan, was more concentrated on mammals, on muscles, and on adaptations. Therefore he was not as concerned with muscle innervation as with their size. Apparently, nobody weighed as many muscles of various mammals as he did. He found measuring the length of muscle fibers not as reliable and did it rarely. So, he lost an opportunity to quantify physiological cross-sectional area (PCSA) of muscles by dividing muscle volume (proportional to mass) by fiber length. PCSA is proportional to the available force of muscle. Giving up with PCSA, Gambaryan often employed muscle mass as a representative of available muscle force for analysis of equilibrium of locomotor postures. This is definitely a mistake, because muscle mass is proportional to available mechanical work per single shortening event, while force is proportional to PCSA.<br>Gambaryan weighed muscles dissected from fresh cadavers as well as from specimens fixed in formalin (2% water solution of formaldehyde) or 70-75% ethanol. Fixed specimens were usually rinsed and kept in water during dissection. Having dissected each muscle, Gambaryan tightly pressed it by hand on a blotter or filter paper to remove extra liquid. He found out that the pressing procedure gives more reliable results because, without it, the masses of the same left and right muscles of the same specimen differ more than they do after blotting. By special study, he came to conclusion that ethanol fixation reduces muscle mass, while formalin fixation preserves the mass close to the fresh value and is, therefore, preferable. However, in his publications Gambaryan almost never presented the absolute muscle masses but used relative values instead. This not only allows to compare the specimens from ethanol with the fresh ones and those from formalin, but also to compare large and small animals. Usually, Gambaryan provided relative mass of a muscle as a ratio of its mass (in %) to the total mass of all forelimb and hindlimb muscles of one side.<br>Being one of numerous Gambaryan's students, I have obtained an archive of absolute muscle masses of a vast variety of mammals stored on his computer as Excel tables. I have no doubt that Gambaryan would be happy to share the results of his titanic labor with colleagues. So, I upload what I have inherited from him for free use now. I start from rodents, the same as Gambaryan started his research. I have cleaned and unified the tables a little for convenience. Mainly, I did not modernize taxonomic names and muscle names; some of them are old-fashioned (e.g., <i>Microtus nivalis</i> and femoral <i>biceps anticus</i>) but a specialist would readily translate them to modern equivalents (e.g., <i>Chionomys nivalis</i> and <i>femorococcygeus</i>, respectively). Also, I did not lose time for improving minor spelling mistakes which are rather numerous but not misleading.<br>Each Excel XLS file corresponds to one specimen and includes one sheet. The specimen taxon is given at the top of the sheet together with optional attributes such as sex, age, body mass, body length (L), tail length (C), pes length (P), ear length (A), capturing locality and date. Then there follow the absolute masses of the forelimb muscles, then of the hindlimb muscles, sometimes – muscles of the head, face, trunk and tail; sometimes, masses of certain internal organs and parts of the skeleton finish the list. There are few cases when individual muscles were weighed together (e.g., '<i>gluteus medius</i>' cell in the table sometimes includes the masses of <i>gluteus medius</i> plus <i>gluteus profundus</i> and/or <i>piriformis</i>). For the bones of some specimens the lengths are provided. In a number of specimens, the masses of counterparts of the two sides of the body are provided in two columns; the columns are labeled 'right' and 'left' if the side is known. In a few cases, an additional column provides fiber lengths of certain muscles.