| maxomys musschenbroekii | Yes | species | eukaryota | rodents | species | 907926 | click here |
| mazama nemorivaga | Yes | species | eukaryota | mammals | species | 397661 | click here |
| meccus pallidipennis | Yes | species | eukaryota | invertebrates | species | 30077 | click here |
| megachile gemula | Yes | species | eukaryota | invertebrates | species | 586908 | click here |
| megachile montivaga | Yes | species | eukaryota | invertebrates | species | 586912 | click here |
| megaderma spasma | Yes | species | eukaryota | mammals | species | 9414 | click here |
| megaselia scalaris | Yes | species | eukaryota | invertebrates | species | 36166 | click here |
| melamphaus faber | Yes | species | | | species | 702479 | click here |
| melanogrammus aeglefinus | Yes | species | eukaryota | vertebrates | species | 8056 | click here |
| melanomys caliginosus | Yes | species | eukaryota | rodents | species | 218793 | click here |
| melanosuchus niger | Yes | species | eukaryota | vertebrates | species | 38656 | click here |
| meles meles | Yes | species | eukaryota | mammals | species | 9662 | click here |
| meliphaga lewinii | Yes | species | eukaryota | vertebrates | species | 390651 | click here |
| melophagus ovinus | Yes | species | eukaryota | invertebrates | species | 452749 | click here |
| melospiza lincolnii | Yes | species | eukaryota | vertebrates | species | 44396 | click here |
| mephitis mephitis | Yes | species | eukaryota | mammals | species | 30548 | click here |
| mepraia gajardoi | Yes | species | eukaryota | invertebrates | species | 722425 | click here |
| mepraia spinolai | Yes | species | eukaryota | invertebrates | species | 162383 | click here |
| meriones crassus | Yes | species | eukaryota | rodents | species | 298887 | click here |
| meriones libycus | Yes | species | eukaryota | rodents | species | 298886 | click here |
| meriones libycus erythrourus | Yes | subspecies | eukaryota | rodents | subspecies | 504100 | click here |
| meriones meridianus | Yes | species | eukaryota | rodents | species | 261754 | click here |
| meriones persicus | Yes | species | | | species | 1395794 | click here |
| meriones shawi | Yes | species | eukaryota | rodents | species | 37435 | click here |
| meriones tamariscinus | Yes | species | eukaryota | rodents | species | 504099 | click here |
| meriones tristrami | Yes | species | eukaryota | rodents | species | 723805 | click here |
| meriones unguiculatus | Yes | species | eukaryota | rodents | species | 10047 | click here |
| mesembrina meridiana | Yes | species | eukaryota | invertebrates | species | 116148 | click here |
| mesocricetus auratus | Yes | species | eukaryota | rodents | species | 10036 | click here |
| metachirus | Yes | | | mammals | genus | 42724 | click here |
| metachirus nudicaudatus | Yes | species | eukaryota | mammals | species | 42725 | click here |
| metacnephia | Yes | | | invertebrates | genus | 61054 | click here |
| metochus | Yes | | | invertebrates | genus | 696903 | click here |
| micoureus demerarae | Yes | species | eukaryota | mammals | species | 42719 | click here |
| micoureus paraguayanus | Yes | species | eukaryota | mammals | species | 225729 | click here |
| microdon dimorphon | Yes | species | eukaryota | invertebrates | species | 115311 | click here |
| microdrosophila | Yes | | | | genus | 1262508 | click here |
| microlophus atacamensis | Yes | species | eukaryota | vertebrates | species | 211986 | click here |
| micronycteris | Yes | | | mammals | genus | 148056 | click here |
| micronycteris megalotis | Yes | species | eukaryota | mammals | species | 148066 | click here |
| micronycteris minuta | Yes | species | eukaryota | mammals | species | 148067 | click here |
| micropterus salmoides | Yes | species | eukaryota | vertebrates | species | 27706 | click here |
| micropygomyia cayennensis | Yes | species | eukaryota | invertebrates | species | 237255 | click here |
| micropygomyia quinquefer | Yes | species | | | species | 1642237 | click here |
| micropygomyia venezuelensis | Yes | species | | | species | 869614 | click here |
| microryzomys minutus | Yes | species | eukaryota | rodents | species | 37025 | click here |
| microtriatoma trinidadensis | Yes | species | eukaryota | invertebrates | species | 741772 | click here |
| microtus agrestis | Yes | species | eukaryota | rodents | species | 29092 | click here |
| microtus arvalis | Yes | species | eukaryota | rodents | species | 47230 | click here |
| microtus guentheri | Yes | species | eukaryota | rodents | species | 269655 | click here |
| microtus montebelli | Yes | species | eukaryota | rodents | species | 79202 | click here |
| migonemyia migonei | Yes | species | | | species | 1642252 | click here |
| millardia meltada | Yes | species | eukaryota | rodents | species | 121583 | click here |
| mimon crenulatum | Yes | species | eukaryota | mammals | species | 148071 | click here |
| miniopterus fuliginosus | Yes | species | eukaryota | mammals | species | 187007 | click here |
| miniopterus natalensis | Yes | species | eukaryota | mammals | species | 291302 | click here |
| miniopterus schreibersii | Yes | species | eukaryota | mammals | species | 9433 | click here |
| miopithecus talapoin | Yes | species | eukaryota | primates | species | 36231 | click here |
| molossus molossus | Yes | species | eukaryota | mammals | species | 27622 | click here |
| monodelphis | Yes | | | mammals | genus | 13615 | click here |
| monodelphis americana | Yes | species | eukaryota | mammals | species | 694061 | click here |
| monodelphis brevicaudata | Yes | species | eukaryota | mammals | species | 203680 | click here |
| monodelphis domestica | Yes | species | eukaryota | mammals | species | 13616 | click here |
| mops condylurus | Yes | species | eukaryota | mammals | species | 258863 | click here |
| mus | Yes | | | rodents | genus | 10088 | click here |
| mus mahomet | Yes | species | | | species | 1582499 | click here |
| mus minutoides | Yes | species | eukaryota | rodents | species | 10105 | click here |
| mus musculus | Yes | species | eukaryota | rodents | species | 10090 | click here |
| mus setulosus | Yes | species | eukaryota | rodents | species | 10102 | click here |
| mus triton | Yes | species | eukaryota | rodents | species | 473865 | click here |
| musca domestica | Yes | species | eukaryota | invertebrates | species | 7370 | click here |
| musca sp. | Yes | no rank | eukaryota | invertebrates | species | 30058 | click here |
| muscina stabulans | Yes | species | eukaryota | invertebrates | species | 57893 | click here |
| mustela lutreola | Yes | species | eukaryota | mammals | species | 9666 | click here |
| mustela nivalis | Yes | species | eukaryota | mammals | species | 36239 | click here |
| mustela putorius furo | Yes | subspecies | eukaryota | mammals | subspecies | 9669 | click here |
| myodes andersoni | Yes | species | eukaryota | rodents | species | 82466 | click here |
| myodes glareolus | Yes | species | eukaryota | rodents | species | 447135 | click here |
| myomyscus brockmani | Yes | species | eukaryota | rodents | species | 485437 | click here |
| myotis | Yes | | | mammals | genus | 9434 | click here |
| myotis albescens | Yes | species | eukaryota | mammals | species | 159322 | click here |
| myotis frater | Yes | species | eukaryota | mammals | species | 187012 | click here |
| myotis keaysi | Yes | species | eukaryota | mammals | species | 159327 | click here |
| myotis lavali | Yes | species | | | species | 2294180 | click here |
| myotis levis | Yes | species | eukaryota | mammals | species | 153285 | click here |
| myotis myotis | Yes | species | eukaryota | mammals | species | 51298 | click here |
| myotis mystacinus | Yes | species | eukaryota | mammals | species | 109479 | click here |
| myotis nigricans | Yes | species | eukaryota | mammals | species | 153286 | click here |
| myotis pequinius | Yes | species | eukaryota | mammals | species | 392004 | click here |
| myotis riparius | Yes | species | eukaryota | mammals | species | 124752 | click here |
| myotis ruber | Yes | species | eukaryota | mammals | species | 159333 | click here |
| myotis siligorensis | Yes | species | eukaryota | mammals | species | 258940 | click here |
| myotis sp. | Yes | species | | | species | 1911917 | click here |
| mystromys albicaudatus | Yes | species | eukaryota | rodents | species | 56239 | click here |
| nabicula flavomarginata | Yes | species | | | species | 1656685 | click here |
| nabis brevis | Yes | species | eukaryota | invertebrates | species | 347967 | click here |
| nabis flavomarginatus | Yes | species | eukaryota | invertebrates | species | 347972 | click here |
| nandinia binotata | Yes | species | eukaryota | mammals | species | 71115 | click here |
| nanger granti | Yes | species | eukaryota | mammals | species | 27591 | click here |
| nariscus | Yes | | | invertebrates | genus | 696892 | click here |