Lepidonotus aff. crosslandi, Monro, 1928

Valencia-Soto, David, 2021, Scale-bearing beauty: Intertidal scale-worms (Polychaeta: Polynoidae) from Punta Blanca (Arequipa, Peru), Zootaxa 5032 (2), pp. 151-194 : 155-166

publication ID

https://doi.org/10.11646/zootaxa.5032.2.1

publication LSID

lsid:zoobank.org:pub:7A904156-23F6-4D88-9F8D-8E3683881F56

persistent identifier

http://treatment.plazi.org/id/9E1D87E2-FFF9-E64A-9CF8-824454CFFBA9

treatment provided by

Plazi

scientific name

Lepidonotus aff. crosslandi
status

 

Lepidonotus aff. crosslandi   peruana Hartmann-Schröder, 1962

Figures 3–8 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8

Lepidonotus sp.   Valencia 2020: 23–29, Figs 8–13 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 .

Material examined. MUSM Nº 4590, 1 specimen, complete, Punta Blanca , Arequipa, Peru, 15°27’38.70”S 75°2’0.60”W, Station 3B, coll. from rocky shore at low tide under rocks, 14 September 2019, by D. Valencia-Soto and D. Valencia-Valencia, pharynx dissected and dissolved for jaw complete examination GoogleMaps   . MUSM Nº 4591, 6 specimens, same sampling data, specimens with non-everted pharynges dissected for superficial jaw examination   . MUSM Nº 4635, 5 specimens, Punta Blanca , Arequipa, Peru, 15°27’37.46”S 75°2’12.24”W, Station 1A, coll. from rocky shore at low tide under rocks in water canals, 14 September 2019, by D. Valencia-Soto and D. Valencia- Valencia, specimens with non-everted pharynges dissected for superficial jaw examination GoogleMaps   . MUSM Nº 4636, 2 specimens, Punta Blanca , Arequipa, Peru, 15°27’37.46”S 75°2’12.24”W, Station 1B, same sampling data and procedure GoogleMaps   . MUSM Nº 4637, 1 specimen, Punta Blanca , Arequipa, Peru, 15°27’39.36”S 75°2’2.98”W, Station 2A, coll. from rocky shore at low tide under rocks, 14 September 2019, by D. Valencia-Soto and D. Valencia-Valencia, dissected for superficial jaw examination GoogleMaps   . MUSM Nº 4638, 2 specimens, Punta Blanca , Arequipa, Peru, 15°27’39.36”S 75°2’2.98”W, Station 2B, same sampling data and procedure GoogleMaps   . MUSM N° 4639 (a), 1 specimen, Punta Blanca , Arequipa, Peru, 15°27’39.36”S 75°2’2.98”W, Station 2C, same sampling data and procedure GoogleMaps   . MUSM Nº 4640, 9 specimens, Punta Blanca , Arequipa, Peru, 15°27’38.70”S 75°2’0.60”W, Station 3A, coll. from rocky shore at low tide under rocks, 14 September 2019, by D. Valencia-Soto and D. Valencia-Valencia, specimens with non-everted pharynges dissected for superficial jaw examination GoogleMaps   . MUSM Nº 4641, 7 specimens, Punta Blanca , Arequipa, Peru, 15°27’38.70”S 75°2’0.60”W, Station 3C, same sampling data and procedure GoogleMaps   .

Four specimens ( MUSM N° 4639b–d) fixed with absolute ethanol, for molecular studies.

Description. Based on specimen MUSM Nº 4590. Individual 17.9 mm long (from tip of median antennae to tip of anal cirri) and 4.9 mm wide with chaetae (4.3 mm without chaetae). Body with 26 segments, short, flattened dorsoventrally, rectangular in cross-section ( Fig. 3A–B View FIGURE 3 ). Prostomium rounded, bilobed, as long as wide, with three antennae placed antero-terminally ( Fig. 3C View FIGURE 3 ). Median ceratophore stout, placed in anterior notch of the prostomium and lateral ceratophores slightly thinner, as anterior projections of the prostomium ( Fig. 3C View FIGURE 3 ). Ceratostyles of all antennae with subdistal swellings and filiform tips: lateral ceratostyles shorter than median ceratostyle. Brownish pigmented bands present at base of all ceratostyles and median ceratophore. Two pairs of dark eyes placed dorsolaterally: anterior pair slightly anterior to widest part of prostomium and posterior pair on posterior part of prostomium ( Fig. 3C View FIGURE 3 ). One pair of stout, conical, smooth palps with abrupt, tapering tips ( Fig. 3C View FIGURE 3 ) and narrow dark pigmented bands along 2/3 of their length. Facial tubercle rounded, with faint dark pigmentation.

Tentaculophores lateral to prostomium, cylindrical with one chaeta each. Tentacular cirri with same appearance as median ceratostyle: with subdistal swelling, filiform tips and dark-pigmented bases. Dorsal and ventral tentacular cirri of similar length. Buccal segment with pair of rounded, nuchal nodules; nuchal fold absent ( Fig. 3C View FIGURE 3 ). Buccal cirri with same appearance of antennae and tentacular cirri but unpigmented. Dorsal cirri with similar appearance of antennae and tentacular cirri, with remnants of pigmented bands ( Fig. 3A–B View FIGURE 3 ). Dorsal tubercles nodular ( Fig. 3B View FIGURE 3 ).

Parapodia with small, somewhat conical notopodia placed anteriorly ( Fig. 4A–C View FIGURE 4 ), with indistinct chaetal lobes. Well-developed neuropodia not deeply incised dorsally and ventrally; prechaetal lobe with subtriangular acicular lobe and postchaetal lobe slightly shorter, distally subtriangular. Neuropodial supra-acicular process and terminal papilla absent ( Fig. 4A–C View FIGURE 4 ). Both rami with aciculae penetrating epidermis ( Fig. 4A–C View FIGURE 4 ). Ventral cirri long in anterior parapodia and shorter in parapodia of the median region of the body, with bulbous bases, filiform tips and smooth surfaces ( Fig. 4A–C View FIGURE 4 ). Nephridial papillae present from 7 th segment, with blunt ends.

Notochaetae arranged in short bundles, with numerous transverse rows of spines: blunt-tipped notochaetae ( Fig. 4D View FIGURE 4 ), in superior and middle positions and capillary notochaetae ( Fig. 4E View FIGURE 4 ), in inferior position. Notochaetae become longer from superior to inferior positions. Neurochaetae stouter than notochaetae, falcate, subdistally thickened, with subdistal rows of spines; rows of spines larger distally than basally. Second parapodium with superior, long, bidentate neurochaetae ( Fig. 4F View FIGURE 4 ) and inferior, shorter, entire-tipped neurochaetae ( Fig. 4G View FIGURE 4 ); third parapodium with long superior, and shorter inferior, bidentate neurochaetae ( Fig. 4H–I View FIGURE 4 ); parapodia from the middle part of the body with superior, long bidentate neurochaetae ( Fig. 4J View FIGURE 4 ) and inferior, shorter entire-tipped neurochaetae ( Fig. 4K View FIGURE 4 ). Pygidium with two anal cirri ( Fig. 3B View FIGURE 3 ).

Twelve pairs of elytra on segments 2, 4, 5, 7, alternating to 23; usually covering all the body, leaving neurochaetae and dorsal cirri exposed. Last three segments non-elytrigerous, covered by last pair of elytra. First pair of elytra slightly rounded ( Fig. 6A View FIGURE 6 ), second and third pairs, reniform ( Fig. 6B–C View FIGURE 6 ) and remaining elytra, ovoid ( Fig. 7A–B View FIGURE 7 ), except for last pair which are slightly triangular ( Fig. 7C View FIGURE 7 ). All elytra brown with white margins, a characteristic white S-shaped spot ( Figs 3 View FIGURE 3 , 6 View FIGURE 6 ) and marginal fringe of papillae arranged on AI and AIII ( Figs 6 View FIGURE 6 , 7 View FIGURE 7 ). Elytrophore scars oval to reniform ( Fig. 6 View FIGURE 6 , 7 View FIGURE 7 ).

All elytral surfaces are covered by rounded translucent papillae (seen from above) ( Fig. 5B, E, F View FIGURE 5 ) and three kinds of hard-walled microtubercles with rounded/oval bases and internal concavities: (a) conical microtubercles with slightly bifid, wrinkled tips (somewhat quadrangular when seen from above) ( Fig. 5A, B, G View FIGURE 5 ) mainly on AI, some on margin of AII and AIII ( Figs 6 View FIGURE 6 , 7 View FIGURE 7 ); (b) truncate microtubercles ( Fig. 5C, H View FIGURE 5 ) mainly on AI and AII, some on AIII and margin of AIV ( Figs 6 View FIGURE 6 , 7 View FIGURE 7 ) and (c) flattened, hemispherical microtubercles ( Fig. 5D, E, I View FIGURE 5 ) mainly on AIII and AIV, some on AI and AII ( Figs 6 View FIGURE 6 , 7 View FIGURE 7 ). Microtubercle morphology changes gradually depending on location, giving rise to transitional forms between zones where each tubercle type predominates (i.e conical tubercles with truncate, wrinkled tips; flattened, slightly wrinkled tubercles and flattened, slightly truncate tubercles).

Like shape, dimensions of microtubercles change gradually over elytral surface depending on location. Except for first pair of elytra, tubercles located on AI and AIII are taller than those present on AII and AIV while tubercle bases are wider when located at AIII, AIV and part of AI. Both height and width of all microtubercle kinds decrease gradually from anterior to posterior pairs of elytra. Size of rounded translucent papillae remain unchanged regardless of location, being the smallest elytral ornamentation.

Pharynx with nine pairs of anterior terminal papillae ( Fig. 8A View FIGURE 8 ). Two pairs of reddish, chitinous, hollow and asymmetric jaws ( Fig. 8B–C View FIGURE 8 ), posterior to papillae. Longer fangs present in dorsal right jaw and ventral left jaw ( Fig. 8B–C View FIGURE 8 ). Denticles absent from jaws ( Fig. 8 View FIGURE 8 ).

Variation. Collected individuals have 26 body segments and range between 7.6–23.4 mm long and 1.9–6.8 mm wide (including chaetae). Of the 34 examined specimens, 13 were ovigerous. Minimum size for ovigerous specimens was 12.1 mm long; however, longer non-ovigerous individuals were observed. Significant morphological differences between non-ovigerous and ovigerous specimens were not observed

Specimens exhibit a few morphological variations: (1) intensity of elytral colour (usually anterior pairs are darker than posterior pairs); (2) length of the entire-tipped neurochaetae present in the second parapodia (usually these are shorter than the bidentate neurochaetae but some individuals have longer entire-tipped neurochaetae); (3) presence of a small notch near the tips of entire-tipped neurochaetae in the second parapodia (usually absent but few individuals, regardless of their length, exhibit it); (4) flattened, hemispherical microtubercles with nearly polygonal bases on AIV (usually rounded) and narrow —or lacking— internal concavities (see Fig. 5E View FIGURE 5 ). None of the variations described above could be correlated to size since these were present regardless of this parameter.

Remarks. The resemblance between collected individuals and L. crosslandi peruana Hartmann-Schröder, 1962   is notable; however, they exhibit a few differences worth mentioning. Specimens differ from the nominal species mainly by the presence of bidentate-tipped neurochaetae in third parapodia, and jaws without denticles. Lack of denticles is persistent in all specimens examined, including individuals smaller than those examined by Hartmann- Schröder (1962a). Presence of some elytral ornamentations (i.e rounded translucent papillae, conical microtubercles with bifid wrinkled tips and truncate microtubercles) appears to be another difference between the two but due to the fact that elytral ornamentations of L. crosslandi peruana Hartmann-Schröder, 1962   were not originally described in detail (see Hartman 1939; Hartmann-Schröder 1962a), it would be necessary to examine the type specimen of L. crosslandi peruana Hartmann-Schröder, 1962   for an adequate assessment.

tubercles with bifid, wrinkled tips.

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Until such time as this is possible, individuals are here considered as a “toothless” variation of L. crosslandi peruana Hartmann-Schröder, 1962   . Comparison between Lepidonotus aff. crosslandi   peruana Hartmann-Schröder, 1962 and other Lepidonotus species   recorded for the Pacific Coast of South America can be found in Table 3.

Distribution. Lepidonotus aff. crosslandi   peruana Hartmann-Schröder, 1962 is here recorded for Punta Blanca (Arequipa, Peru). Lepidonotus crosslandi peruana Hartmann-Schröder, 1962   has previously been recorded from Callao (type locality), Independencia Bay ( Hartman 1939, as Lepidonotus crosslandi Monro   ), Cañete ( Tasso et al. 2018), Lima ( Paredes et al. 1999) and Pisco ( Paredes et al. 1988), Peru.

Ecology. Found along with individuals of Harmothoe aff. hirsuta Johnson, 1897   (described below). As far as was observed, specimens of both species did not exhibit aggressive behaviours to each other.

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Phyllodocida

Family

Polynoidae

Genus

Lepidonotus

Loc

Lepidonotus aff. crosslandi

Valencia-Soto, David 2021
2021
Loc

Lepidonotus sp.

Valencia, D. 2020: 23
2020