Hypsolebias hamadryades

description

Description. Morphometric data appear in Table 3. Body relatively deep, compressed. Greatest body depth at vertical just anterior to pelvic-fin base. Dorsal and ventral profiles of head and trunk slightly convex, approximately straight on caudal peduncle. Head narrow, sub-triangular in lateral view. Jaws short, teeth numerous, conical, irregularly arranged; outer teeth hypertrophied, inner teeth small and numerous. Vomerine teeth absent. Gill-rakers on first branchial arch 3 + 9, gill-rakers short, straight, without denticles. Urogenital papilla conical in males, pocket-shaped in females, slightly projecting over anterior part of anal fin. Dorsal and anal fins relatively short, extremities rounded to slightly pointed in both sexes, without filamentous rays. Caudal fin rounded. Pectoral fin elliptical, posterior margin reaching base of 7 th anal-fin ray in males, reaching anus in females. Pelvic fin small, tip reaching between base of 2 nd and 3 rd anal-fin rays in males, reaching urogenital papilla in females; pelvic-fin bases medially united. Dorsal-fin origin anterior to anal-fin origin in males, anal-fin origin at vertical between base of 1 st and 3 rd dorsal-fin rays; dorsal-fi

Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the Sao Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae)

diagnosis

Diagnosis. Hypsolebias hamadryades is distinguished from all other species of the H. magnificus complex by the absence of dark greenish grey bars on the anterior portion of the flank in males (vs. presence) and presence of transverse blue stripes on the unpaired fins in males wider than interspace (vs. transverse series of dots or stripes narrower than interspace). It also differs from all other species of the complex by the following combination of character states relative to the male colour pattern: dorsal fin with transverse blue stripes and one basal row of blue dots (vs. rows of blue dots on the whole fin in H. picturatus); anal fin with transverse blue stripes on most portion of the fin (vs. dots and short vermiculate marks arranged on most part of the fin in H. gardneri, H. harmonicus and H. picturatus); and most portion of caudal fin with blue bars (vs. anterior half of caudal fin with transverse rows of blue dots, posterior half with transverse blue bars in H. gardneri and H. harmonicus, or dots on the entire fin in H. picturatus), and the presence of eight to ten light red bars between humeral region and the anterior part of the caudal peduncle (vs. six or seven in H. ma

Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the Sao Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae)

distribution

Distribution and conservation. Hypsolebias hamadryades is only known from a pool in the floodplains of the Gorutuba River, within the town of Janauba, Minas Gerais, Brazil (15 ° 48 ' 06 " S, 43 ° 19 ' 19 " W, altitude about 530 m a. s. l.; Figure 3). This area has been studied since January 2002 (Costa, 2006), but H. hamadryades was first collected only in 2017. Previous field studies revealed two endemic seasonal killifishes, H. janaubensis (Costa, 2006) and Cynolebias gorotuba Costa, 2017, as well as an intense process of urbanization which result in the complete extirpation of all temporary pools studied between 2002 and 2010 (Costa 2017). The type locality pool of H. hamadryades was only found in January 2017, since it was hidden by a dense Caatinga forest. The pool occupied an area of about 100 m 2 and was about 1 m deep. The whole pool was densely populated by adult specimens of H. janaubensis, whereas individuals of H. hamadryades, mostly juvenile specimens below 20 mm SL including, were found only in a small part of the pool containing shaded zones, near the pool margins, where bushes were concentrated. The largest males exhibited damaged caudal fins, indicating possible te

Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the Sao Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae)

etymology

Etymology. The name hamadryades is an allusion to the occurrence of the new species in the forested part of a Caatinga temporary pool. This name was used by the Bavarian naturalist Karl Friedrich Philipp von Martius for the Caatinga in his classification of vegetation formations of Brazil, in which he used names of Greek mythological beings to name each Brazilian phytogeographical province. The name is opportune by referring to hamadryades, a particular kind of Greek nymph entity that is believed to be associated to trees, vanishing when trees die. Similarly, field studies have shown that populations of species of the H. magnificus group became extinct after marginal deforestation (see discussion below).

Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the Sao Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae)