Hanleya harasewychi, Sirenko, 2014

Sirenko, Boris, 2014, Composition of the genus Hanleya (Mollusca: Polyplacophora: Lepidopleurida), with the description of two new species, Journal of Natural History 48 (45 - 48), pp. 2913-2945 : 2917-2923

publication ID	https://doi.org/ 10.1080/00222933.2014.963722
DOI	https://doi.org/10.5281/zenodo.4784140
persistent identifier	https://treatment.plazi.org/id/513E7520-D309-FFD8-FDD5-5604B369FA09
treatment provided by	Carolina
scientific name	Hanleya harasewychi
status	sp. nov.

Treatment

Hanleya harasewychi View in CoL sp. nov.

( Figures 2–5 View Figure 2 View Figure 3 View Figure 4 View Figure 5 )

Type material

Holotype, USNM 93189, BL = 15.0 mm, now disarticulated, consisting of a mount of the shell, perinotum and radula, and 3 paratypes, USNM 323067, 454683, 454684.

Type locality

22 mi ESE of Cape Hatteras, North Carolina (35.0800° N, 75.0530° W) U.S. Fish Commission Steamer Albatross , Sta. 2595, 1885, in 63 fathoms (115.2 m), sand, temp, 75°F (holotype) GoogleMaps .

Material examined

Holotype, USNM 93189, BL = 15.0 mm, 22 mi ESE of Cape Hatteras, North Carolina (35.0800° N, 75.0530° W) U.S. Fish Commission Steamer Albatross , Sta. 2595, 1885, in 63 fathoms (115.2 m), sand, temp, 75°F GoogleMaps ; Paratype 1, USNM 323067, BL = 5.0 mm, off Key West , Florida (24.28° N, 81.50° W), U.S. Fish Commission Steamer Albatross, Sta. 2317, 45 fathoms (81.9 m) on coral, 75°F (water column temperature?) GoogleMaps ; Paratype 2, USNM 454683, BL = 3.0 mm, off Fowey Light , Florida (25.35262° N, 80.4508° W), sponges, Eolis Sta. 188, 48 fathoms (87.4 m), Henderson Coll., 1915 GoogleMaps ; Paratype 3, USNM 454684, BL = 3.0 mm, Off Fowey Light , Florida (25.35262° N, 80.4508° W), Eolis Sta. 109, 40 fathoms (72.8 m), Henderson Coll., 1914 GoogleMaps .

Distribution

Off Cape Hatteras, North Carolina to the Florida Keys , in 73–115 m.

Diagnosis

Animal small (to 15.0 mm), elevated (dorsal elevation of valve V 0.36), back rounded. Head valves, lateral areas of intermediate valves, postmucronal areas sculptured with roundish granules arranged without distinct order, pleural areas of intermediate valves sculptured with long granules, ratio of granule length to granule width in pleural areas, 2.5–3.0; interspaces between rows of granules on pleural areas twice as large as width of granules; width of jugal sinus equal to width of apophyses in intermediate valves; insertion plate of tail valve well developed and pectinate; each granule contains a single megalaesthete and 12–13 micraesthetes. Valves and girdle buff coloured, spotted with brown and white. Dorsal spicules of girdle flat with one central longitudinal rib distally terminated with sharp beak. Radula with 15 transverse rows of mature teeth; exterior denticle of major lateral teeth of radula half the size of interior one, width of central denticle is equal to its length.

Description

Holotype dry, curled, about 15.0 mm long, 6.0 mm wide when straightened ( Figure 2F and H View Figure 2 ). Valves rounded ( Figure 2E View Figure 2 ). Head valve semicircular ( Figure 2A View Figure 2 ) posterior margin widely V-shaped, tegmentum sculptured with roundish granules arranged without regular pattern. Intermediate valves more or less rectangular ( Figure 2B View Figure 2 ), side margins evenly rounded, posterior margin nearly straight except for a small projecting apex, lateral areas not elevated, with sculpture as in head valve ( Figure 2G View Figure 2 ), pleural areas sculptured with elongated oval granules (about 180 × 60 μm) arranged in longitudinal rows, interspaces nearly twice as broad as width of granules, tegmentum of jugal area sculptured with small, elongated granules arranged without pattern ( Figure 3B View Figure 3 ). Each granule contains a single megalaesthete and 12–13 micraesthetes ( Figure 4E View Figure 4 ). Tail valve as wide as head valve, more or less oval; posterior margin well rounded, anterior margin straight to concave ( Figure 2B View Figure 2 ); mucro central, highly elevated, prominent; length of antemucronal area equal to that of postmucronal area ( Figure 2D View Figure 2 ), the latter deeply concave, sculptured like the head valve; antemucronal area sculptured like central area of intermediate valves ( Figure 3D View Figure 3 ). Tegmentum and girdle buff coloured with white and brown blotches.

Articulamentum white, solid, blotched with rose in front of the central portion. Apophyses wide, long, with primordium of insertion plates extending nearly to end of lateral areas ( Figures 3E View Figure 3 and 5C View Figure 5 ), jugal sinus as wide as apophyses. Insertion plates well developed both in head and tail valves ( Figure 3A and C View Figure 3 ) (length of insertion plates 0.4–0.5 mm in head valve, 0.2 mm in tail valve); insertion plates obsoletely striate in head valve, pectinated in tail valve.

Girdle narrow in present condition, densely covered with small, slender, slightly curved, pointed scales ( Figures 3E View Figure 3 and 4B View Figure 4 ) each with a single, central, longitudinal rib distally terminated by a sharp beak (≤60–70 × 14–18 μm), as well as randomly dispersed straight to slightly curved needles ( Figure 4A View Figure 4 ) varying in size from 230 × 20 μm to 470 × 30 μm. Marginal needles like dorsal needles ( Figure 4C View Figure 4 ). Ventral scales narrow, sharply pointed, reaching 80 × 17 μm in middle part of girdle, 120 × 20 μm near its margin ( Figure 4C and D View Figure 4 ).

Radula 4.5 mm long, with 15 transverse rows of mineralised mature teeth (total about 20 rows). Central tooth short, almost rectangular, with narrow blade ( Figure 4F View Figure 4 ). Major lateral tooth with tridentate cusp ( Figure 4G and H View Figure 4 ), central denticle largest, as wide as long, exterior denticle smallest, half size of interior denticle.

Gills merobranchial, adanal, without interspace, with 14 ctenidia per side, gills extending from the end of valve VI to anus. It is not possible to find a nephropore or gonopore in these dry specimens.

Age variability

With increasing body size, the width/length ratio of intermediate valves measured using valve V decreases from 2.7 (BL = 5.0 mm) to 2.3 (BL = 15.0 mm), as does the ratio of head valve length/head valve insertion plate length, from 6.0 (BL = 5.0 mm) to 4.6 (BL = 15.0 mm) ( Figures 2A, B View Figure 2 and 5A, B, D View Figure 5 ). The smaller paratype (BL = 5.0 mm) has similar dorsal spicules and needles that are slightly shorter and half as wide as those of the holotype ( Figure 4I and J View Figure 4 ). Granules on jugal area in paratype and holotype are similar but on the pleural area of paratype a little bit longer than that of holotype ( Figures 2G View Figure 2 , 3B, D View Figure 3 , 5E, F View Figure 5 ).

Comparative remarks ( Table 1 View Table 1 )

Hanleya harasewychi sp. nov. is readily distinguished from its congeners by its buff colour with white and brown blotches, rounded back, longer granules and larger interspaces on pleural areas of valves, fewer rows of mature teeth in the radula, and a shorter central denticle on the major lateral tooth of the radula. The colour of the tegmentum remains visible after preservation and is a reliable taxonomic character.

Hanleya mediterranea sp. nov. has similar dorsal girdle scales, but differs from H. harasewychi in having larger, joined granules on the tegmentum (elongate in H. harasewychi ), as well as similar-sized exterior and interior denticles on the major lateral tooth (very small exterior denticle in H. harasewychi ).

Hanleya nagelfar , which also has wide apophyses, differs from H. harasewychi in having dorsal girdle spicules that are ribbed in young specimens, but nearly smooth and less developed in mature adults, and in lacking a pectinated insertion plate on the tail valve.

Hanleya tropicalis , which also has a small exterior denticle on the major lateral tooth of the radula ( Figure 8K View Figure 8 ), can be distinguished from the new species by its more elevated shell and absence of an insertion plate in the tail valve.

Hanleya brachyplax also has a well-developed insertion plate on the tail valve, but can be separated from H. harasewychi by its white colour, shorter granules and fewer interspaces on pleural areas of valves, longer central denticle on the major lateral tooth of the radula, as well as by having longer and narrower apophyses, and a less dorsally elevated shell.

Etymology

This new species honours Dr. M. G. Harasewych, Curator of Marine Molluscs, Department of Invertebrate Zoology, National Museum of National History, Smithsonian Institution for his contributions to malacology and for his help and support during the preparation of this publication.