Dactyloscopidae
Creators: name: Hastings, Philip A.
name: Springer, Victor G.
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Perciformes
Dactyloscopidae

description: Dactyloscopidae   11) Dactyloscopus. Dactyloscopus byersi Dawson was described based on specimens from Mexico (south of the Gulf California) to Panama (type locality: Manzanillo, Colima, Mexico). Dactyloscopus byersi heraldi Dawson was described based on specimens from southern Baja northward along the southwestern coast of Baja (type locality: Cabo San Lucas, Mexico). The two differ in a number of features (Dawson, 1975) including pattern of scalation above the curved portion of the lateral line (one row present in byersi versus absent in heraldi), number of anal-fin rays (31-35, modally 34 in byersi versus 29-33, modally 32 in heraldi), number of upper lip fimbriae (13-18, modally 15 in byersi versus 11-14, modally 12 in heraldi), number of preopercular sensory pores (pore number increases with size, but more present in byersi of comparable sizes), and coloration (chevron markings prominent on the side posteriad in byersi versus weak or absent in heraldi; dark bars present on the dorsum of heraldi versus absent in byersi). These features clearly separate these forms, warranting recognition of each of them as species.   
 12) Dactyloscopus. Dawson (1975) recognized two subspecies of Dactyloscopus fimbriatus (Reid), the nominate form from Central and South America (type locality: Cape Elena, Ecuador) and Dactyloscopus fimbriatus elongatus Myers & Wade from Mexico, including the southwestern coast of Baja California, and the Gulf of California southward to Oaxaca (type locality: Cabo Corrientes, Jalisco, Mexico). Dawson (1975) reported that these forms are readily distinguished by several features including the number of upper lip fimbriae (15-19, mean = 17.4 in fimbriatus versus 13-17, mean = 15.0 in elongatus), number of segmented anal-fin rays (36-39, modally 37 in fimbriatus versus 38-41, modally 39 in elongatus), and number of preopercular canal pores (mean = 14.8 in fimbriatus versus mean = 8.6 in elongatus), selected body proportions and coloration (distinct marking present in fimbriatus but weak to absent in elongatus). Consequently, these forms clearly warrant recognition as separate species.   
 13) Dactyloscopus. Dawson (1975) recognized three subspecies of Dactyloscopus pectoralis Gill, the nominate subspecies from the Gulf of California (type locality: Cabo San Lucas, Mexico), Dactyloscopus pectoralis fallax Dawson from Mexico south of the Gulf to Ecuador (type locality: Chacala, Nayarit, Mexico), and Dactyloscopus pectoralis insulatus Dawson from the Islas Revillagigedo (type locality: Isla San Benedicto). These forms differ in a number of morphological features (Dawson, 1975) including scalation patterns (scales absent above the lateral line in pectoralis versus present in the other two), number of upper lip fimbriae (modally 9 in pectoralis, 11 in falax and 10-11 in insulatus), number of preopercular canal pores (modally 5 in pectoralis, 6 in fallax and 10 in insulatus), and selected fin-ray counts. In addition, the labial fimbriae are branched in fallax but unbranched in the other two. Consequently, these features clearly distinguish these three forms and warrant their recognition as separate species.   
 14) Myxodagnus. Myxodagnus opercularis Gill was described based on specimens collected by John Xantus at Cabo San Lucas, Mexico. The subspecies Myxodagnus opercularis walkeri Dawson was based on type material from mainland Mexico (type locality: Chacala, Nayarit) and non-type material from Costa Rica.   
 Dawson (1976) reported that these forms differ in several features including number of upper lip fimbriae (7- 8 in opercularis versus 10-11 in walkeri), number preopercular canal pores (one in opercularis versus 2-3 in walkeri), preorbital length (greater in walkeri) and coloration (distinct suborbital bar present in opercularis, absent in walkeri). These differences clearly distinguish these forms and warrant their recognition as separate species.
description: Published as part of Hastings, Philip A. & Springer, Victor G., 2009, Recognizing diversity in blennioid fish nomenclature (Teleostei: Blennioidei), pp. 3-14 in Zootaxa 2120 on pages 9-10, DOI: 10.5281/zenodo.188099