Petrarca morula, GRYGIER, 1985

Kolbasov, Gregory A., Savchenko, Alexandra S., Yu, Meng-Chen, Tsao, Yao-Feng, Ganmanee, Monthon & Chan, Benny K. K., 2023, Integrative taxonomy, larval biology and functional morphology of the little known gall-forming coral endoparasite Petrarca (Thecostraca: Ascothoracida), Zoological Journal of the Linnean Society 198, pp. 767-801 : 777-780

publication ID	https://doi.org/ 10.1093/zoolinnean/zlad009
publication LSID	lsid:zoobank.org:pub:A2863AB5-855B-4549-89EC-A57C46140CD9
DOI	https://doi.org/10.5281/zenodo.8152382
persistent identifier	https://treatment.plazi.org/id/03FA8E1E-AB4A-FF86-46E9-FE79FDDDF973
treatment provided by	Plazi
scientific name	Petrarca morula
status

Treatment

PETRARCA MORULA GRYGIER, 1985

( FIGS 1G View Figure 1 , 8–13 View Figure 8 View Figure 9 View Figure 10 View Figure 11 View Figure 12 View Figure 13 )

Petrarca morula Grygier, 1985: 1036–1038 , fig. 6, Grygier & Nojima, 1995: 93–96, fig. 18 (probably another species).

Material examined: Four specimens in Turbinaria bifrons Brüggemann, 1877 , 22 ° 40 ʹ 39.2 ″ N, 121°28 ʹ 57.2 ″ E, Green Island (L ǜ d ǎ o), Taiwan, 24.04.2015, at a depth of 4–20 m. GoogleMaps

Here we provide additional descriptions based on SEM analysis that supplements Grygier’s (1985) original description.

Diagnosis: Carapace spherical, with large lumpy inflations, without radial ridges; carapace margin not crenulated; ventral side of carapace with large conical papillae, lateral surface with small papillae. Mandibles with 10–14 sharp, simple teeth; maxillules with small denticles; six pairs of thoracopods, first thoracopod setiform; penis with relatively small, rounded rami.

Description: Living specimens pink, with dark inclusions at the anterior part of carapace ( Fig. 1G View Figure 1 ); tip of penis often extending out of carapace ( Fig. 8 View Figure 8 ). Adult (mature) specimens 2.13–2.42 mm long (1.2– 3.8 mm from the Grygier material), 1.85–1.96 mm high (0.9–4.0 mm from the Grygier material), 2.00– 2.24 mm wide (1.0– 4.6 mm from the Grygier material) ( Figs 8 View Figure 8 , 11A View Figure 11 ). Carapace ( Figs 8 View Figure 8 , 11A View Figure 11 ) spherical; valves with conspicuous rounded lumpy inflations (8–14), without radial ridges, dorsal and posterior margins not crenulated; long, conical papillae with a tiny terminal pore on anterior half of ventral margin ( Fig. 11A, D View Figure 11 ). Cuticle on the lateral external and posteriodorsal internal surfaces of carapace with dense, polygonal, small swellings or bumps ( Fig. 11B, H View Figure 11 ). Small volcano-shaped papillae with tiny a terminal pore and microscopic pores inserted between bumps on external surface of carapace ( Fig. 11B, C, E View Figure 11 ). Thin cuticular lining (mantle) of inner surface of carapace with rows of dense ctenoid scales in central part ( Fig. 11F, G, I View Figure 11 ).

Body inflated, curved, enclosed between carapace valves, tip of penis almost adjoins oral cone ( Figs 8 View Figure 8 , 12A View Figure 12 ). Cephalon with large adductor muscle lying above big oral cone flanked by five-segmented antennules. Thorax with sinusoid arched dorsal margin, without distinct segmentation, with clusters of rudimentary uniramous thoracopods ( Fig. 12A View Figure 12 ). Abdomen with massive first segment bearing long penis and vestigial rear part ( Fig. 12A View Figure 12 ).

scales on lateral surface enlarged in circle outline). F, medial languette, lateral view (groups of denticles on anterior margin enlarged in oval outline, basal ‘pore-field’ enlarged in circle outline). G, distal part of mandible (lower part of cutting edge enlarged in oval outline). H, maxillule (lower half of cutting edge enlarged in oval outline). Abbreviations: ae, aesthetasc; cl, claw; clg, claw guard. Scale bars in µm.

Antennules W-shaped, with little armament (external sculpture) on two distal segments ( Figs 9A–C View Figure 9 , 12B–H View Figure 12 ). First segment irregularly rectangular, narrowing somewhat distally; second segment rectangular; third segment triangular, narrowing toward lower/ventral margin; fourth segment trapezoid, with slightly curved ventral margin, short distal seta inserted at anteriodorsal corner ( Fig. 12C View Figure 12 ). Fifth segment narrow, rectangular, slightly shorter than fourth and armed with sensory and grasping structures ( Figs 9B, C View Figure 9 , 12D–H View Figure 12 ). Short massive curved claw with smooth concave margin. Three rudimentary setae at base of claw and to each side ( Figs 9B, C View Figure 9 , 12F View Figure 12 ); tiny pores (five to seven) on inner and outer lateral sides ( Figs 9B, C View Figure 9 , 12D, E View Figure 12 ). Claw sheathed by large, oval claw guard ( Fig. 12F View Figure 12 ); claw guard with three vestigial, distal setae with a terminal pore ( Fig. 12H View Figure 12 ); developed subdistal aesthetasc almost half as long as claw guard, terminates with two outgrowths, rudimentary seta with a terminal pore at base of aesthetasc ( Fig. 12F, H View Figure 12 ). Ventral (postaxial) margin of fifth segment and claw guard with wrinkled cuticle bearing tiny pores ( Fig. 12G View Figure 12 ).

Oral cone prominent ( Figs 9D View Figure 9 , 12A, I View Figure 12 ); labrum prow-shaped, exterior with dense ctenoid scales ( Fig. 12I, J View Figure 12 ); mandibles elongated, cutting edge straight, with 14 sharp, simple teeth (ten in Grygier specimen) ( Fig. 9E View Figure 9 ); maxillules with sclerotized, triangular distal parts, inner margin with small denticles ( Fig. 9F, G View Figure 9 ); fused maxillae ending in a pair of short, rounded lobes, with dense ctenoid scales on lateral surfaces ( Figs 9H View Figure 9 , 12I View Figure 12 ).

Studied specimens with six pairs of thoracopods; thoracopod 1 setiform ( Fig. 10A View Figure 10 ); thoracopods 2–6 ( Fig. 10B View Figure 10 ) uniramous, unsegmented, grouped in cluster and arranged in an unorderly sequence in lateral view; thoracopods 2–4 longer and wider than thoracopods 5 and 6. Cuticle of thoracopods 2–6 with rows of dense and long ctenoid scales ( Fig. 13A, B View Figure 13 ). Batteries of ampuliform seminal receptacles ( Fig. 10B View Figure 10 ) associated with thoracopods 2–5 (~11, 6, 8 and 7 receptacles, respectively).

Long, terminally bifid penis originates from large first abdominal segment ( Figs 10D View Figure 10 , 12A View Figure 12 , 13C View Figure 13 ). Shaft of penis supports two small, rounded rami about 125 µm long; distal part of penis, including rami, bearing numerous short but wide conical setae. Rest of abdomen vestigial, consisting of two segments bearing rare ctenoid scales and tiny pores; posterior end of abdomen with cleavage with few terminal denticles ( Figs 10C View Figure 10 , 13D–F View Figure 13 ).

Remarks: Grygier & Nojima (1995) indicated that both P. morula and P. goanna may represent ‘the extremes of morphological variability in a single species’. However, along with molecular evidence provided here, there are a number of morphological features that can be used to distinguish these species. Thus, P. morula differs from P. goanna in having numerous long conical papillae on the anterioventral part of carapace vs. only a few inconspicuous ventral papillae in P. goanna ; exterior of carapace with small volcano-shaped papillae (absent in P. goanna ) but without radial ribs and crenulated margin (present in P. goanna ); teeth of the mandible are simple and fewer (simple and bifid teeth present in P. goanna ); inner margin of maxillules with small denticles (bigger teeth in P. goanna ); subterminal aesthetasc of claw guard terminates with two outgrowths (four in P. goanna ).