Apterichtus caecus ( Linnaeus 1758 ) Blache & Bauchot 1972 :711 Vahl 1794 :156 Muraena caeca Linnaeus 1758 Lacepède 1800 :134 Muraena caeca Linnaeus 1758 Delaroche 1809 :325 A review of the finless snake eels of the genus Apterichtus (Anguilliformes: Ophichthidae), with the description of five new species Hibino, Yusuke Zootaxa 2015 3941 1 49 78 FYGW Linnaeus 1758 Linnaeus 1758 [151,588,1015,1042] Actinopterygii Ophichthidae Apterichtus Animalia Anguilliformes 7 56 Chordata species caecus     Apterichtus caecus( Linnaeus 1758):  Blache & Bauchot 1972:711.    Caecula apterygia  Vahl 1794:156, an unneeded substitute name for  Muraena caeca Linnaeus 1758.    Caecilia branderiana  Lacepède 1800:134, an unneeded substitute name for  Muraena caeca Linnaeus 1758.    Apterichtus caecus:  Delaroche 1809:325.   Diagnosis. An elongate species with: tail 1.6–1.7, head 12–15, and body depth 56–83 intotal length; 4 preopercular pores and 5 pores in supratemporal canal; teeth conical, uniserial on jaws, becoming biserial on vomer of large specimens; 8–14 vomerine teeth; body coloration (when fresh) ochre with numerous small dark brown spots, those spots forming a continuous mid-dorsal band, yellowish on ventral surface, head with dark brown spots over a pale background, a prominent horizontal white patch beneath and behind the orbit ( Fig. 3); and MVF 52–134, total vertebrae 132–139 (n=6).  Size. The largest known specimen is 60 cm.   Distribution. Known from 0–85 mdepth, usually in fine sand. Western and eastern Mediterranean, eastern Atlantic south to Azores, Madeira, and the Canary islands.   Remarks.  Muraena caecawas described by Linnaeus (1758)from the Mediterranean in a terse 42 word unillustrated description. Subsequent authors agree that the typespecimen is lost. The next mention of  M. caecawas that of Duméril (1806)who created the generic name  Apterichtusfor  caeca. The first comprehensive treatment of the species was that of Delaroche (1809)in which he well-described and illustrated a specimen from Iviça, a Balearic Islandin the Mediterranean off Spain. He considered Linnaeus’s description to be “très-exacte, mais trèsincomplete” and on the basis of his “28 ½ centimeter” specimen provided an extensive description and illustration. The specimen now resides in the Muséum National d'Histoire Naturelle (Paris) and was redescribed and illustrated by Blache and Bauchot (1972:711–714)along with another specimen from eastern Africa. Blache and Bauchot (p. 711) erroneously stated that the specimen (“n o MNHN, Paris: 2125”) collected by Delaroche from the Baléares was 497 mmTL. Their other specimen (“n o MNHN, Paris: 1884–426”) was said to be 284 mmTL and to have been collected by Vaillant off east Africa. Because of the disagreement with the length so precisely cited by Delaroche we presume that Blache and Bauchot erroneously reversed the collection data and sizes of the two specimens, and we presume that the 284 mmspecimen is that of Delaroche. We have examined the Delaroche specimen and find it to be an adequate, albeit slightly twisted, specimen. It has 137 total vertebrae (52 preanal) and the following measurements (in mm): total length 284; head length 21.3; trunk length 94.7; jaw length ca. 8.4 (the jaw is cut at the rictus on both sides); snout length 3.6; eye diameter 1.0; interorbital width 1.3; body depth at gill opening ca. 5.4; and body width at gill opening ca. 4.6. Its dentition was illustrated by Blache and Bauchot ( Figure 7, p. 713). It has the following cephalic pores: single median interorbital and temporal pores; supraorbital pores 1+4, infraorbital pores 5+2, supratemporal pores 5, lower jaw pores 5, preopercular pores 4; lateral-line pores difficult to count accurately due to small size and waxy exudate, 8 inbranchial region. Our description of  Apterichtus caecusis primarily based on Pereira and Aguiar’s (1979) description of five Azorean specimens, as well as Blache and Bauchot’s (1972) description and illustrations, and McCosker’s examination of the neotypeand a specimen from Italy. Blache and Bauchot’s second specimen ( 497 mm) has broadly separated biserial vomerine teeth. It agrees in other body proportions, pores and vertebrae (135). Wirtz et al. (2008: Figure 3) published a color photograph of an  A. caecustaken at night in 14 mfrom Madeira. They also published a color photograph ( Figure 2) taken in 20 mfrom Madeira of what appears to be  A. caecus; it well demonstrates the ochre cephalic coloration of that species.  Blache and Bauchot (1972)and Leiby (1990)remarked that  A. anguiformisand  A. caecushave been confused with each other during the last two centuries and that most earlier references to adults and larvae are not clearly attributable to either species. In that no typesexisted for Linnaeus’  Muraena caeca, Blache and Bauchot (1972:709–710)analyzed its meager description and concluded that  caecamost probably was based on the Mediterranean species of  Apterichtuswhich has 135–138 vertebrae … and a preanal distance of 40.5–42.3% of the total length, rather than the species with the higher vertebral count (150–157),  A. anguiformis. We agree with their conclusion and feel that it is appropriate to designate a neotypefor  Apterichtus caecus( Linnaeus 1758)in our revision. We herein do so and designate MNHN-IC-0000-2125 to be the neotype.   Material examined. 2 specimens, 284–504 mmTL, including the neotype(MNHN-IC-0000- 2125, 284 mm), from Iviça, a Balearic Islandin the Mediterranean off Spain. From Italy: Strait of Messina, MCZ 40861, 504 mm.