Petrarca rubus Kolbasov & Savchenko & Yu & Tsao & Ganmanee & Chan 2023, SP. NOV.
Creators: name: Kolbasov, Gregory A.
name: Savchenko, Alexandra S.
name: Yu, Meng-Chen
name: Tsao, Yao-Feng
name: Ganmanee, Monthon
name: Chan, Benny K. K.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Laurida
Petrarcidae
Petrarca
Petrarca rubus

description: PETRARCA RUBUS SP. NOV.
(FIGS 1I, 19–25)
Z o o b a n k R e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: BA716B70-D5B8-49A1-AF02-670876B5E887
Material examined: Four specimens (including holotype) in Turbinaria bifrons and Turbinaria sp., 22°40 ′ 39.2 ″ N, 121°28 ′ 57.2 ″ E, Green Island (L ǜ d ǎ o), Taiwan, 24.04.2015, at 4–20 m depth. Glycerin slide of the dissected holotype (no. Mg 1249) with the carapace valves, antennules, mouth parts, and rest of the body with thoracopods and penis, and SEM stub of paratype (no. Mg 1251) with the carapace valves and the body are deposited in the Zoological Museum of Moscow State University in Moscow, Russian Federation.
Diagnosis: Carapace roughly ovoid, carapace valves of adults with crenulated margins formed by protruding outer ends of six to seven radially directed dorsal and posterior irregular ridges; ridge exterior with irregular lumpy inflations; ventral side of carapace with numerous, large conical papillae, lateral surface with small papillae. Mandibles with 20 sharp, simple and bifid teeth; teeth of the maxillules in lower half with spiniform tips and tending to form two rows; six pairs of thoracopods, first thoracopod setiform; penis with relatively small, rounded cylindrical rami.
Etymology. From Latin rubus, raspberry (Rubus idaeus L.), referring to the shape and colour of t h e c a r a p a c e i n l i v i n g i n d i v i d u a l s o f t h e n e w species resembling ripe raspberries. It is a noun in apposition.
Description: Living specimens pink or crimson-coloured (Fig. 1I). Adult (mature) specimens 4.35– 5.71 mm long, 4.43–5.65 mm high (Figs 19A–C, 22A); young (juvenile) specimen (Fig. 19D) 1.52 mm long and 1.54 mm high. Carapace roughly ovoid in adults (Figs 19A–C, 22A) and spherical in young specimen (Fig. 19D); valves with short anteriodorsal hinge line; lateral surfaces with six to seven radial ridges with irregular lumpy inflations. These inflations are less developed in the anterior part of adults and in young specimens. Dorsal and posterior margins of valve crenulated due to carapace ridges (Figs 19A–C, 22A, E). Ventral margin curved, with numerous, large conical papillae (Fig. 22C) with a central micropore at the tip (Fig. 22D). Cuticle on the lateral external and internal surfaces of carapace with dense, polygonal, small swellings or bumps, with papillae on the external side and tiny pores on the internal side (Fig. 22B, F).
Body inflated, curved, enclosed between carapace valves, tip of penis close to oral cone (Fig. 22E). Cephalon with large adductor muscle lying above big oral cone flanked by five-segmented antennules. Thorax with arched dorsal margin, with small hump in posterior part but without distinct segmentation, with clusters of rudimentary uniramous thoracopods (Fig. 22E). Abdomen with massive first segment bearing long penis and vestigial rear part (Fig. 22E).
Antennules somewhat prehensile, with little armament (external sculpture) on two distal segments (Figs 20A, 23A). First segment irregularly rectangular, narrowing somewhat distally; second segment rectangular; third segment almost triangular, narrowing toward lower/ventral margin; fourth segment slightly longer than wide, with slightly curved ventral margin, short distal seta inserted at anteriodorsal corner (Figs 20A, D, 23A, B). Fifth segment rectangular, narrowing towards distal end, shorter and narrower than fourth and armed with sensory and grasping structures, ventral/postaxial margin uneven, dorsal/preaxial margin concave (Figs 20B, C, 23A, C–I). Short, massive curved claw with smooth concave margin arising from distal end of segment. Three rudimentary setae at base of claw and to each side (Figs 20B, C, 23E); tiny pores (six to eight) on inner and outer lateral sides (Figs 20B, C, 23C, D). Claw sheathed by large, hood-shaped, oval claw guard on posteriodistal corner (Figs 20B, C, 23A); claw guard with three vestigial, distal setae each with a terminal pore (Fig. 23H); developed subterminal aesthetasc almost half as long as claw guard, terminating with three long outgrowths and rudimentary subterminal seta; rudimentary seta at base of aesthetasc (Fig. 23F, G). Ventral (postaxial) margin of fifth segment and claw guard with wrinkled cuticle bearing tiny pores (Fig. 23I). Oral cone prominent, consisting of massive labrum underlaid posteriorly with massive, fused maxillae, unpaired medial languette and paired mandibles and maxillules (Figs 20E–I, 22E, 24). Massive prow-shaped labrum with short posteriolateral extensions, leaving maxillae largely exposed, dense ctenoid scales on the exterior (Fig. 24A). Mandibles (Figs 20F, G, 24B–D) elongated, outer/upper margin with dense, thin setae in the middle, cutting edge straight, with 20 sharp, simple or rarely bifid teeth and three small spinules(or reduced setae?) in the middle. Maxillules (Figs 20H, 24E–H) with sclerotized, triangular distal parts, inner margin with ~27 teeth, teeth in upper half with blunt tips, while those in lower half smaller, irregular, with spiniform tips and tending to form two irregular rows; dense basal pores forming ‘pore-field’ (Fig. 24H). Fused maxillae (Figs 20I, 24I–K) with dense ctenoid scales on lateral surfaces (Fig. 24K), distal ends with rounded zones of sclerotized, thick and wrinkled cuticle without denticles, pores or setules (Fig. 24J).
Six pairs of thoracopods; thoracopods 2–6 uniramous, unsegmented, grouped in cluster and arranged in an unorderly sequence in lateral view (Figs 21B, 22E). Thoracopod 1 setiform (Figs 21A, 25A); thoracopods 2–4 conical, longer and wider than thoracopods 5 and 6. Batteries of ampuliform seminal receptacles (Fig. 21B) associated with thoracopods 2–5 (~18–20, 20–22, 12 and 9 receptacles, respectively). Cuticle of thoracopods 2–6 with dense and long ctenoid scales (Fig. 25B).
Long (~0.8–1.0 mm) and massive, terminally bifid penis originates from large first abdominal segment (Fig. 22E). Shaft of penis supports two relatively small, rounded cylindrical rami about 200–250 µm long; distal part of penis, including rami, bearing numerous short but wide conical setae (Figs 21D, 25D). Rest of abdomen vestigial, consisting of two indistinct segments; posterior end of abdomen with shallow cleft (Figs 21C, 25C).
Remarks: The new species Petrarca rubus is similar to the other three congeners, P. morula, P. goanna and P. nozaaeai, in utilizing Turbinaria corals as hosts. These species are characterized by the large lumpy inflations of the carapace, which are absent in other species of Petrarca. Moreover, P. goanna and P. rubus represent a complex of cryptic species and can only be distinguished by a few ultrastructural details: (1) the presence of numerous large, long conical papillae on the anterioventral part of carapace in P. rubus (only a few in P. goanna) and papillae on the external lateral surface of carapace (absent in P. goanna); (2) the ultrastructure of antennular aesthetasc having three long terminal outgrowths in P. rubus instead of four in P. goanna; and (3) rounded cylindrical rami of penis in P. rubus but squarish rami in P. goanna.
Petrarca rubus differs from P. morula and P. nozaaeai in having radial ribs and a crenulated margin of the carapace valves and the presence of bifid teeth on the mandibles.
MOLECULAR ANALYSIS
description: Published as part of 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), pp. 767-801 in Zoological Journal of the Linnean Society 198 on pages 786-791, DOI: 10.1093/zoolinnean/zlad009, http://zenodo.org/record/8152364